Update v8.9.9

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This section lists all updates associated with version 8.9.9 of the Fleet integration Prebuilt Security Detection Rules.

Rule Description Status Version

Network Activity Detected via Kworker

This rule monitors for network connections from a kworker process. kworker, or kernel worker, processes are part of the kernel’s workqueue mechanism. They are responsible for executing work that has been scheduled to be done in kernel space, which might include tasks like handling interrupts, background activities, and other kernel-related tasks. Attackers may attempt to evade detection by masquerading as a kernel worker process.

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1

Attempt to Clear Kernel Ring Buffer

Monitors for the deletion of the kernel ring buffer events through dmesg. Attackers may clear kernel ring buffer events to evade detection after installing a Linux kernel module (LKM).

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1

Potential Malicious File Downloaded from Google Drive

Identifies potential malicious file download and execution from Google Drive. The rule checks for download activity from Google Drive URL, followed by the creation of files commonly leveraged by or for malware. This could indicate an attempt to run malicious scripts, executables or payloads.

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Potential Cookies Theft via Browser Debugging

Identifies the execution of a Chromium based browser with the debugging process argument, which may indicate an attempt to steal authentication cookies. An adversary may steal web application or service session cookies and use them to gain access web applications or Internet services as an authenticated user without needing credentials.

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104

WebServer Access Logs Deleted

Identifies the deletion of WebServer access logs. This may indicate an attempt to evade detection or destroy forensic evidence on a system.

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104

Tampering of Bash Command-Line History

Adversaries may attempt to clear or disable the Bash command-line history in an attempt to evade detection or forensic investigations.

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104

Elastic Agent Service Terminated

Identifies the Elastic endpoint agent has stopped and is no longer running on the host. Adversaries may attempt to disable security monitoring tools in an attempt to evade detection or prevention capabilities during an intrusion. This may also indicate an issue with the agent itself and should be addressed to ensure defensive measures are back in a stable state.

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105

Masquerading Space After Filename

This rules identifies a process created from an executable with a space appended to the end of the filename. This may indicate an attempt to masquerade a malicious file as benign to gain user execution. When a space is added to the end of certain files, the OS will execute the file according to it’s true filetype instead of it’s extension. Adversaries can hide a program’s true filetype by changing the extension of the file. They can then add a space to the end of the name so that the OS automatically executes the file when it’s double-clicked.

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5

Timestomping using Touch Command

Timestomping is an anti-forensics technique which is used to modify the timestamps of a file, often to mimic files that are in the same folder.

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104

Security Software Discovery via Grep

Identifies the use of the grep command to discover known third-party macOS and Linux security tools, such as Antivirus or Host Firewall details.

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107

Virtual Machine Fingerprinting via Grep

An adversary may attempt to get detailed information about the operating system and hardware. This rule identifies common locations used to discover virtual machine hardware by a non-root user. This technique has been used by the Pupy RAT and other malware.

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104

Potential Reverse Shell Activity via Terminal

Identifies the execution of a shell process with suspicious arguments which may be indicative of reverse shell activity.

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107

Suspicious JAVA Child Process

Identifies suspicious child processes of the Java interpreter process. This may indicate an attempt to execute a malicious JAR file or an exploitation attempt via a JAVA specific vulnerability.

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206

Hosts File Modified

The hosts file on endpoints is used to control manual IP address to hostname resolutions. The hosts file is the first point of lookup for DNS hostname resolution so if adversaries can modify the endpoint hosts file, they can route traffic to malicious infrastructure. This rule detects modifications to the hosts file on Microsoft Windows, Linux (Ubuntu or RHEL) and macOS systems.

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107

Zoom Meeting with no Passcode

This rule identifies Zoom meetings that are created without a passcode. Meetings without a passcode are susceptible to Zoombombing. Zoombombing is carried out by taking advantage of Zoom sessions that are not protected with a passcode. Zoombombing refers to the unwanted, disruptive intrusion, generally by Internet trolls and hackers, into a video conference call. In a typical Zoombombing incident, a teleconferencing session is hijacked by the insertion of material that is lewd, obscene, racist, or antisemitic in nature, typically resulting of the shutdown of the session.

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102

Threat Intel IP Address Indicator Match

This rule is triggered when an IP address indicator from the Threat Intel Filebeat module or integrations has a match against a network event.

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4

Threat Intel Hash Indicator Match

This rule is triggered when a hash indicator from the Threat Intel Filebeat module or integrations has a match against an event that contains file hashes, such as antivirus alerts, process creation, library load, and file operation events.

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5

Threat Intel Windows Registry Indicator Match

This rule is triggered when a Windows registry indicator from the Threat Intel Filebeat module or integrations has a match against an event that contains registry data.

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4

Threat Intel URL Indicator Match

This rule is triggered when a URL indicator from the Threat Intel Filebeat module or integrations has a match against an event that contains URL data, like DNS events, network logs, etc.

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4

Network Activity Detected via cat

This rule monitors for the execution of the cat command, followed by a connection attempt by the same process. Cat is capable of transfering data via tcp/udp channels by redirecting its read output to a /dev/tcp or /dev/udp channel. This activity is highly suspicious, and should be investigated. Attackers may leverage this capability to transfer tools or files to another host in the network or exfiltrate data while attempting to evade detection in the process.

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Potential Protocol Tunneling via Chisel Client

This rule monitors for common command line flags leveraged by the Chisel client utility followed by a connection attempt. Chisel is a command-line utility used for creating and managing TCP and UDP tunnels, enabling port forwarding and secure communication between machines. Attackers can abuse the Chisel utility to establish covert communication channels, bypass network restrictions, and carry out malicious activities by creating tunnels that allow unauthorized access to internal systems.

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3

Potential Protocol Tunneling via Chisel Server

This rule monitors for common command line flags leveraged by the Chisel server utility followed by a received connection within a timespan of 1 minute. Chisel is a command-line utility used for creating and managing TCP and UDP tunnels, enabling port forwarding and secure communication between machines. Attackers can abuse the Chisel utility to establish covert communication channels, bypass network restrictions, and carry out malicious activities by creating tunnels that allow unauthorized access to internal systems.

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3

Suspicious Utility Launched via ProxyChains

This rule monitors for the execution of suspicious linux tools through ProxyChains. ProxyChains is a command-line tool that enables the routing of network connections through intermediary proxies, enhancing anonymity and enabling access to restricted resources. Attackers can exploit the ProxyChains utility to hide their true source IP address, evade detection, and perform malicious activities through a chain of proxy servers, potentially masking their identity and intentions.

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Potential Linux Tunneling and/or Port Forwarding

This rule monitors for a set of Linux utilities that can be used for tunneling and port forwarding. Attackers can leverage tunneling and port forwarding techniques to bypass network defenses, establish hidden communication channels, and gain unauthorized access to internal resources, facilitating data exfiltration, lateral movement, and remote control.

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3

Suspicious Network Activity to the Internet by Previously Unknown Executable

This rule monitors for network connectivity to the internet from a previously unknown executable located in a suspicious directory to a previously unknown destination ip. An alert from this rule can indicate the presence of potentially malicious activity, such as the execution of unauthorized or suspicious processes attempting to establish connections to unknown or suspicious destinations such as a command and control server. Detecting and investigating such behavior can help identify and mitigate potential security threats, protecting the system and its data from potential compromise.

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5

Potential Protocol Tunneling via EarthWorm

Identifies the execution of the EarthWorm tunneler. Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection and network filtering, or to enable access to otherwise unreachable systems.

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108

Sensitive Files Compression

Identifies the use of a compression utility to collect known files containing sensitive information, such as credentials and system configurations.

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207

Potential Linux Credential Dumping via Unshadow

Identifies the execution of the unshadow utility which is part of John the Ripper, a password-cracking tool on the host machine. Malicious actors can use the utility to retrieve the combined contents of the /etc/shadow and /etc/password files. Using the combined file generated from the utility, the malicious threat actors can use them as input for password-cracking utilities or prepare themselves for future operations by gathering credential information of the victim.

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Linux init (PID 1) Secret Dump via GDB

This rule monitors for the potential memory dump of the init process (PID 1) through gdb. Attackers may leverage memory dumping techniques to attempt secret extraction from privileged processes. Tools that display this behavior include "truffleproc" and "bash-memory-dump". This behavior should not happen by default, and should be investigated thoroughly.

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Potential Linux Local Account Brute Force Detected

Identifies multiple consecutive login attempts executed by one process targeting a local linux user account within a short time interval. Adversaries might brute force login attempts across different users with a default wordlist or a set of customly crafted passwords in an attempt to gain access to these accounts.

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Potential External Linux SSH Brute Force Detected

Identifies multiple external consecutive login failures targeting a user account from the same source address within a short time interval. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to these accounts.

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5

Potential Internal Linux SSH Brute Force Detected

Identifies multiple internal consecutive login failures targeting a user account from the same source address within a short time interval. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to these accounts.

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9

Potential Successful Linux FTP Brute Force Attack Detected

An FTP (file transfer protocol) brute force attack is a method where an attacker systematically tries different combinations of usernames and passwords to gain unauthorized access to an FTP server, and if successful, the impact can include unauthorized data access, manipulation, or theft, compromising the security and integrity of the server and potentially exposing sensitive information. This rule identifies multiple consecutive authentication failures targeting a specific user account from the same source address and within a short time interval, followed by a successful authentication.

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Potential Successful Linux RDP Brute Force Attack Detected

An RDP (Remote Desktop Protocol) brute force attack involves an attacker repeatedly attempting various username and password combinations to gain unauthorized access to a remote computer via RDP, and if successful, the potential impact can include unauthorized control over the compromised system, data theft, or the ability to launch further attacks within the network, jeopardizing the security and confidentiality of the targeted system and potentially compromising the entire network infrastructure. This rule identifies multiple consecutive authentication failures targeting a specific user account within a short time interval, followed by a successful authentication.

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4

Potential Successful SSH Brute Force Attack

Identifies multiple SSH login failures followed by a successful one from the same source address. Adversaries can attempt to login into multiple users with a common or known password to gain access to accounts.

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9

Potential Linux Credential Dumping via Proc Filesystem

Identifies the execution of the mimipenguin exploit script which is linux adaptation of Windows tool mimikatz. Mimipenguin exploit script is used to dump clear text passwords from a currently logged-in user. The tool exploits a known vulnerability CVE-2018-20781. Malicious actors can exploit the cleartext credentials in memory by dumping the process and extracting lines that have a high probability of containing cleartext passwords.

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5

Potential OpenSSH Backdoor Logging Activity

Identifies a Secure Shell (SSH) client or server process creating or writing to a known SSH backdoor log file. Adversaries may modify SSH related binaries for persistence or credential access via patching sensitive functions to enable unauthorized access or to log SSH credentials for exfiltration.

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108

Attempt to Disable IPTables or Firewall

Adversaries may attempt to disable the iptables or firewall service in an attempt to affect how a host is allowed to receive or send network traffic.

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Attempt to Disable Syslog Service

Adversaries may attempt to disable the syslog service in an attempt to an attempt to disrupt event logging and evade detection by security controls.

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108

Base16 or Base32 Encoding/Decoding Activity

Adversaries may encode/decode data in an attempt to evade detection by host- or network-based security controls.

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107

System Binary Copied and/or Moved to Suspicious Directory

This rule monitors for the copying or moving of a system binary to a suspicious directory. Adversaries may copy/move and rename system binaries to evade detection. Copying a system binary to a different location should not occur often, so if it does, the activity should be investigated.

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File made Immutable by Chattr

Detects a file being made immutable using the chattr binary. Making a file immutable means it cannot be deleted or renamed, no link can be created to this file, most of the file’s metadata can not be modified, and the file can not be opened in write mode. Threat actors will commonly utilize this to prevent tampering or modification of their malicious files or any system files they have modified for purposes of persistence (e.g .ssh, /etc/passwd, etc.).

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Potential Disabling of AppArmor

This rule monitors for potential attempts to disable AppArmor. AppArmor is a Linux security module that enforces fine-grained access control policies to restrict the actions and resources that specific applications and processes can access. Adversaries may disable security tools to avoid possible detection of their tools and activities.

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3

Potential Disabling of SELinux

Identifies potential attempts to disable Security-Enhanced Linux (SELinux), which is a Linux kernel security feature to support access control policies. Adversaries may disable security tools to avoid possible detection of their tools and activities.

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107

ESXI Timestomping using Touch Command

Identifies instances where the touch command is executed on a Linux system with the "-r" flag, which is used to modify the timestamp of a file based on another file’s timestamp. The rule targets specific VM-related paths, such as "/etc/vmware/", "/usr/lib/vmware/", or "/vmfs/*". These paths are associated with VMware virtualization software, and their presence in the touch command arguments may indicate that a threat actor is attempting to tamper with timestamps of VM-related files and configurations on the system.

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5

File Deletion via Shred

Malware or other files dropped or created on a system by an adversary may leave traces behind as to what was done within a network and how. Adversaries may remove these files over the course of an intrusion to keep their footprint low or remove them at the end as part of the post-intrusion cleanup process.

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107

File Permission Modification in Writable Directory

Identifies file permission modifications in common writable directories by a non-root user. Adversaries often drop files or payloads into a writable directory and change permissions prior to execution.

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207

Creation of Hidden Files and Directories via CommandLine

Users can mark specific files as hidden simply by putting a "." as the first character in the file or folder name. Adversaries can use this to their advantage to hide files and folders on the system for persistence and defense evasion. This rule looks for hidden files or folders in common writable directories.

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107

Creation of Hidden Shared Object File

Identifies the creation of a hidden shared object (.so) file. Users can mark specific files as hidden simply by putting a "." as the first character in the file or folder name. Adversaries can use this to their advantage to hide files and folders on the system for persistence and defense evasion.

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Kernel Module Removal

Kernel modules are pieces of code that can be loaded and unloaded into the kernel upon demand. They extend the functionality of the kernel without the need to reboot the system. This rule identifies attempts to remove a kernel module.

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107

System Log File Deletion

Identifies the deletion of sensitive Linux system logs. This may indicate an attempt to evade detection or destroy forensic evidence on a system.

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109

Potential Hidden Process via Mount Hidepid

Identifies the execution of mount process with hidepid parameter, which can make processes invisible to other users from the system. Adversaries using Linux kernel version 3.2+ (or RHEL/CentOS v6.5+ above) can hide the process from other users. When hidepid=2 option is executed to mount the /proc filesystem, only the root user can see all processes and the logged-in user can only see their own process. This provides a defense evasion mechanism for the adversaries to hide their process executions from all other commands such as ps, top, pgrep and more. With the Linux kernel hardening hidepid option all the user has to do is remount the /proc filesystem with the option, which can now be monitored and detected.

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5

Potential Defense Evasion via PRoot

Identifies the execution of the PRoot utility, an open-source tool for user-space implementation of chroot, mount --bind, and binfmt_misc. Adversaries can leverage an open-source tool PRoot to expand the scope of their operations to multiple Linux distributions and simplify their necessary efforts. In a normal threat scenario, the scope of an attack is limited by the varying configurations of each Linux distribution. With PRoot, it provides an attacker with a consistent operational environment across different Linux distributions, such as Ubuntu, Fedora, and Alpine. PRoot also provides emulation capabilities that allow for malware built on other architectures, such as ARM, to be run.The post-exploitation technique called bring your own filesystem (BYOF), can be used by the threat actors to execute malicious payload or elevate privileges or perform network scans or orchestrate another attack on the environment. Although PRoot was originally not developed with malicious intent it can be easily tuned to work for one.

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5

Suspicious Renaming of ESXI Files

Identifies instances where VMware-related files, such as those with extensions like ".vmdk", ".vmx", ".vmxf", ".vmsd", ".vmsn", ".vswp", ".vmss", ".nvram", and ".vmem", are renamed on a Linux system. The rule monitors for the "rename" event action associated with these file types, which could indicate malicious activity.

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5

Suspicious Renaming of ESXI index.html File

Identifies instances where the "index.html" file within the "/usr/lib/vmware/*" directory is renamed on a Linux system. The rule monitors for the "rename" event action associated with this specific file and path, which could indicate malicious activity.

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5

ESXI Discovery via Find

Identifies instances where the find command is started on a Linux system with arguments targeting specific VM-related paths, such as "/etc/vmware/", "/usr/lib/vmware/", or "/vmfs/*". These paths are associated with VMware virtualization software, and their presence in the find command arguments may indicate that a threat actor is attempting to search for, analyze, or manipulate VM-related files and configurations on the system.

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5

ESXI Discovery via Grep

Identifies instances where a process named grep, egrep, or pgrep is started on a Linux system with arguments related to virtual machine (VM) files, such as "vmdk", "vmx", "vmxf", "vmsd", "vmsn", "vswp", "vmss", "nvram", or "vmem". These file extensions are associated with VM-related file formats, and their presence in grep command arguments may indicate that a threat actor is attempting to search for, analyze, or manipulate VM files on the system.

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5

Enumeration of Kernel Modules

Loadable Kernel Modules (or LKMs) are pieces of code that can be loaded and unloaded into the kernel upon demand. They extend the functionality of the kernel without the need to reboot the system. This identifies attempts to enumerate information about a kernel module.

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207

Hping Process Activity

Hping ran on a Linux host. Hping is a FOSS command-line packet analyzer and has the ability to construct network packets for a wide variety of network security testing applications, including scanning and firewall auditing.

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107

Nping Process Activity

Nping ran on a Linux host. Nping is part of the Nmap tool suite and has the ability to construct raw packets for a wide variety of security testing applications, including denial of service testing.

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107

Potential Network Scan Executed From Host

This threshold rule monitors for the rapid execution of unix utilities that are capable of conducting network scans. Adversaries may leverage built-in tools such as ping, netcat or socat to execute ping sweeps across the network while attempting to evade detection or due to the lack of network mapping tools available on the compromised host.

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2

Potential Pspy Process Monitoring Detected

This rule leverages auditd to monitor for processes scanning different processes within the /proc directory using the openat syscall. This is a strong indication for the usage of the pspy utility. Attackers may leverage the pspy process monitoring utility to monitor system processes without requiring root permissions, in order to find potential privilege escalation vectors.

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Sudo Command Enumeration Detected

This rule monitors for the usage of the sudo -l command, which is used to list the allowed and forbidden commands for the invoking user. Attackers may execute this command to enumerate commands allowed to be executed with sudo permissions, potentially allowing to escalate privileges to root.

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SUID/SGUID Enumeration Detected

This rule monitors for the usage of the "find" command in conjunction with SUID and SGUID permission arguments. SUID (Set User ID) and SGID (Set Group ID) are special permissions in Linux that allow a program to execute with the privileges of the file owner or group, respectively, rather than the privileges of the user running the program. In case an attacker is able to enumerate and find a binary that is misconfigured, they might be able to leverage this misconfiguration to escalate privileges by exploiting vulnerabilities or built-in features in the privileged program.

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4

Unusual User Privilege Enumeration via id

This rule monitors for a sequence of 20 "id" command executions within 1 second by the same parent process. This behavior is unusual, and may be indicative of the execution of an enumeration script such as LinPEAS or LinEnum. These scripts leverage the "id" command to enumerate the privileges of all users present on the system.

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3

Virtual Machine Fingerprinting

An adversary may attempt to get detailed information about the operating system and hardware. This rule identifies common locations used to discover virtual machine hardware by a non-root user. This technique has been used by the Pupy RAT and other malware.

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107

Abnormal Process ID or Lock File Created

Identifies the creation of a Process ID (PID), lock or reboot file created in temporary file storage paradigm (tmpfs) directory /var/run. On Linux, the PID files typically hold the process ID to track previous copies running and manage other tasks. Certain Linux malware use the /var/run directory for holding data, executables and other tasks, disguising itself or these files as legitimate PID files.

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211

Potential curl CVE-2023-38545 Exploitation

Detects potential exploitation of curl CVE-2023-38545 by monitoring for vulnerable command line arguments in conjunction with an unusual command line length. A flaw in curl version ⇐ 8.3 makes curl vulnerable to a heap based buffer overflow during the SOCKS5 proxy handshake. Upgrade to curl version >= 8.4 to patch this vulnerability. This exploit can be executed with and without the use of environment variables. For increased visibility, enable the collection of http_proxy, HTTPS_PROXY and ALL_PROXY environment variables based on the instructions provided in the setup guide of this rule.

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3

File Creation, Execution and Self-Deletion in Suspicious Directory

This rule monitors for the creation of a file, followed by its execution and self-deletion in a short timespan within a directory often used for malicious purposes by threat actors. This behavior is often used by malware to execute malicious code and delete itself to hide its tracks.

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3

File Transfer or Listener Established via Netcat

A netcat process is engaging in network activity on a Linux host. Netcat is often used as a persistence mechanism by exporting a reverse shell or by serving a shell on a listening port. Netcat is also sometimes used for data exfiltration.

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109

Potential Upgrade of Non-interactive Shell

Identifies when a non-interactive terminal (tty) is being upgraded to a fully interactive shell. Attackers may upgrade a simple reverse shell to a fully interactive tty after obtaining initial access to a host, in order to obtain a more stable connection.

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2

Netcat Listener Established via rlwrap

Monitors for the execution of a netcat listener via rlwrap. rlwrap is a readline wrapper, a small utility that uses the GNU Readline library to allow the editing of keyboard input for any command. This utility can be used in conjunction with netcat to gain a more stable reverse shell.

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2

Network Connection via Recently Compiled Executable

This rule monitors a sequence involving a program compilation event followed by its execution and a subsequent network connection event. This behavior can indicate the set up of a reverse tcp connection to a command-and-control server. Attackers may spawn reverse shells to establish persistence onto a target system.

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3

Interactive Terminal Spawned via Perl

Identifies when a terminal (tty) is spawned via Perl. Attackers may upgrade a simple reverse shell to a fully interactive tty after obtaining initial access to a host.

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107

Potential Linux Hack Tool Launched

Monitors for the execution of different processes that might be used by attackers for malicious intent. An alert from this rule should be investigated further, as hack tools are commonly used by blue teamers and system administrators as well.

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2

Process Started from Process ID (PID) File

Identifies a new process starting from a process ID (PID), lock or reboot file within the temporary file storage paradigm (tmpfs) directory /var/run directory. On Linux, the PID files typically hold the process ID to track previous copies running and manage other tasks. Certain Linux malware use the /var/run directory for holding data, executables and other tasks, disguising itself or these files as legitimate PID files.

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108

Binary Executed from Shared Memory Directory

Identifies the execution of a binary by root in Linux shared memory directories: (/dev/shm/, /run/shm/, /var/run/, /var/lock/). This activity is to be considered highly abnormal and should be investigated. Threat actors have placed executables used for persistence on high-uptime servers in these directories as system backdoors.

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Interactive Terminal Spawned via Python

Identifies when a terminal (tty) is spawned via Python. Attackers may upgrade a simple reverse shell to a fully interactive tty after obtaining initial access to a host.

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Potential Code Execution via Postgresql

This rule monitors for suspicious activities that may indicate an attacker attempting to execute arbitrary code within a PostgreSQL environment. Attackers can execute code via PostgreSQL as a result of gaining unauthorized access to a public facing PostgreSQL database or exploiting vulnerabilities, such as remote command execution and SQL injection attacks, which can result in unauthorized access and malicious actions, and facilitate post-exploitation activities for unauthorized access and malicious actions.

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5

Linux Restricted Shell Breakout via Linux Binary(s)

Identifies the abuse of a Linux binary to break out of a restricted shell or environment by spawning an interactive system shell. The activity of spawning a shell from a binary is not common behavior for a user or system administrator, and may indicate an attempt to evade detection, increase capabilities or enhance the stability of an adversary.

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111

Deprecated - Potential Reverse Shell via Suspicious Parent Process

This detection rule detects the creation of a shell through a suspicious parent child relationship. Any reverse shells spawned by the specified utilities that use a forked process to initialize the connection attempt will be captured through this rule. Attackers may spawn reverse shells to establish persistence onto a target system.

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6

Potential Reverse Shell via Background Process

Monitors for the execution of background processes with process arguments capable of opening a socket in the /dev/tcp channel. This may indicate the creation of a backdoor reverse connection, and should be investigated further.

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3

Potential Reverse Shell via Java

This detection rule identifies the execution of a Linux shell process from a Java JAR application post an incoming network connection. This behavior may indicate reverse shell activity via a Java application.

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5

Potential Reverse Shell via Suspicious Child Process

This detection rule detects the creation of a shell through a suspicious process chain. Any reverse shells spawned by the specified utilities that are initialized from a single process followed by a network connection attempt will be captured through this rule. Attackers may spawn reverse shells to establish persistence onto a target system.

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6

Potential Meterpreter Reverse Shell

This detection rule identifies a sample of suspicious Linux system file reads used for system fingerprinting, leveraged by the Metasploit Meterpreter shell to gather information about the target that it is executing its shell on. Detecting this pattern is indicative of a successful meterpreter shell connection.

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3

Potential Reverse Shell via Suspicious Binary

This detection rule detects the creation of a shell through a chain consisting of the execution of a suspicious binary (located in a commonly abused location or executed manually) followed by a network event and ending with a shell being spawned. Stageless reverse tcp shells display this behaviour. Attackers may spawn reverse shells to establish persistence onto a target system.

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6

Potential Reverse Shell

This detection rule identifies suspicious network traffic patterns associated with TCP reverse shell activity. This activity consists of a parent-child relationship where a network event is followed by the creation of a shell process. An attacker may establish a Linux TCP reverse shell to gain remote access to a target system.

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6

Potential Reverse Shell via UDP

This detection rule identifies suspicious network traffic patterns associated with UDP reverse shell activity. This activity consists of a sample of an execve, socket and connect syscall executed by the same process, where the auditd.data.a0-1 indicate a UDP connection, ending with an egress connection event. An attacker may establish a Linux UDP reverse shell to bypass traditional firewall restrictions and gain remote access to a target system covertly.

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3

Suspicious Content Extracted or Decompressed via Funzip

Identifies when suspicious content is extracted from a file and subsequently decompressed using the funzip utility. Malware may execute the tail utility using the "-c" option to read a sequence of bytes from the end of a file. The output from tail can be piped to funzip in order to decompress malicious code before it is executed. This behavior is consistent with malware families such as Bundlore.

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4

Suspicious System Commands Executed by Previously Unknown Executable

This rule monitors for the execution of several commonly used system commands executed by a previously unknown executable located in commonly abused directories. An alert from this rule can indicate the presence of potentially malicious activity, such as the execution of unauthorized or suspicious processes attempting to run malicious code. Detecting and investigating such behavior can help identify and mitigate potential security threats, protecting the system and its data from potential compromise.

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104

Suspicious Mining Process Creation Event

Identifies service creation events of common mining services, possibly indicating the infection of a system with a cryptominer.

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5

BPF filter applied using TC

Detects when the tc (transmission control) binary is utilized to set a BPF (Berkeley Packet Filter) on a network interface. Tc is used to configure Traffic Control in the Linux kernel. It can shape, schedule, police and drop traffic. A threat actor can utilize tc to set a bpf filter on an interface for the purpose of manipulating the incoming traffic. This technique is not at all common and should indicate abnormal, suspicious or malicious activity.

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107

Suspicious Data Encryption via OpenSSL Utility

Identifies when the openssl command-line utility is used to encrypt multiple files on a host within a short time window. Adversaries may encrypt data on a single or multiple systems in order to disrupt the availability of their target’s data and may attempt to hold the organization’s data to ransom for the purposes of extortion.

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4

Suspicious Termination of ESXI Process

Identifies instances where VMware processes, such as "vmware-vmx" or "vmx," are terminated on a Linux system by a "kill" command. The rule monitors for the "end" event type, which signifies the termination of a process. The presence of a "kill" command as the parent process for terminating VMware processes may indicate that a threat actor is attempting to interfere with the virtualized environment on the targeted system.

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5

Suspicious File Changes Activity Detected

This rule identifies a sequence of 100 file extension rename events within a set of common file paths by the same process in a timespan of 1 second. Ransomware is a type of malware that encrypts a victim’s files or systems and demands payment (usually in cryptocurrency) in exchange for the decryption key. One important indicator of a ransomware attack is the mass encryption of the file system, after which a new file extension is added to the file.

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7

Potential Linux Ransomware Note Creation Detected

This rule identifies a sequence of a mass file encryption event in conjunction with the creation of a .txt file with a file name containing ransomware keywords executed by the same process in a 1 second timespan. Ransomware is a type of malware that encrypts a victim’s files or systems and demands payment (usually in cryptocurrency) in exchange for the decryption key. One important indicator of a ransomware attack is the mass encryption of the file system, after which a new file extension is added to the file.

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7

High Number of Process Terminations

This rule identifies a high number (10) of process terminations via pkill from the same host within a short time period.

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110

Potential SSH-IT SSH Worm Downloaded

Identifies processes that are capable of downloading files with command line arguments containing URLs to SSH-IT’s autonomous SSH worm. This worm intercepts outgoing SSH connections every time a user uses ssh.

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2

Connection to External Network via Telnet

Telnet provides a command line interface for communication with a remote device or server. This rule identifies Telnet network connections to publicly routable IP addresses.

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106

Connection to Internal Network via Telnet

Telnet provides a command line interface for communication with a remote device or server. This rule identifies Telnet network connections to non-publicly routable IP addresses.

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106

Chkconfig Service Add

Detects the use of the chkconfig binary to manually add a service for management by chkconfig. Threat actors may utilize this technique to maintain persistence on a system. When a new service is added, chkconfig ensures that the service has either a start or a kill entry in every runlevel and when the system is rebooted the service file added will run providing long-term persistence.

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108

Modification of OpenSSH Binaries

Adversaries may modify SSH related binaries for persistence or credential access by patching sensitive functions to enable unauthorized access or by logging SSH credentials for exfiltration.

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107

Cron Job Created or Changed by Previously Unknown Process

Linux cron jobs are scheduled tasks that can be leveraged by malicious actors for persistence, privilege escalation and command execution. By creating or modifying cron job configurations, attackers can execute malicious commands or scripts at predefined intervals, ensuring their continued presence and enabling unauthorized activities.

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6

Dynamic Linker Copy

Detects the copying of the Linux dynamic loader binary and subsequent file creation for the purpose of creating a backup copy. This technique was seen recently being utilized by Linux malware prior to patching the dynamic loader in order to inject and preload a malicious shared object file. This activity should never occur and if it does then it should be considered highly suspicious or malicious.

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106

Suspicious File Creation in /etc for Persistence

Detects the manual creation of files in specific etc directories, via user root, used by Linux malware to persist and elevate privileges on compromised systems. File creation in these directories should not be entirely common and could indicate a malicious binary or script installing persistence mechanisms for long term access.

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110

Potential Persistence Through init.d Detected

Files that are placed in the /etc/init.d/ directory in Unix can be used to start custom applications, services, scripts or commands during start-up. Init.d has been mostly replaced in favor of Systemd. However, the "systemd-sysv-generator" can convert init.d files to service unit files that run at boot. Adversaries may add or alter files located in the /etc/init.d/ directory to execute malicious code upon boot in order to gain persistence on the system.

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7

Kernel Module Load via insmod

Detects the use of the insmod binary to load a Linux kernel object file. Threat actors can use this binary, given they have root privileges, to load a rootkit on a system providing them with complete control and the ability to hide from security products. Manually loading a kernel module in this manner should not be at all common and can indicate suspcious or malicious behavior.

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107

Persistence via KDE AutoStart Script or Desktop File Modification

Identifies the creation or modification of a K Desktop Environment (KDE) AutoStart script or desktop file that will execute upon each user logon. Adversaries may abuse this method for persistence.

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108

Potential Linux Backdoor User Account Creation

Identifies the attempt to create a new backdoor user by setting the user’s UID to 0. Attackers may alter a user’s UID to 0 to establish persistence on a system.

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5

Linux Group Creation

Identifies attempts to create a new group. Attackers may create new groups to establish persistence on a system.

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3

Potential Remote Code Execution via Web Server

Identifies suspicious commands executed via a web server, which may suggest a vulnerability and remote shell access. Attackers may exploit a vulnerability in a web application to execute commands via a web server, or place a backdoor file that can be abused to gain code execution as a mechanism for persistence.

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6

Linux User Account Creation

Identifies attempts to create new users. Attackers may add new users to establish persistence on a system.

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3

Linux User Added to Privileged Group

Identifies attempts to add a user to a privileged group. Attackers may add users to a privileged group in order to establish persistence on a system.

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5

Potential Persistence Through MOTD File Creation Detected

Message of the day (MOTD) is the message that is presented to the user when a user connects to a Linux server via SSH or a serial connection. Linux systems contain several default MOTD files located in the "/etc/update-motd.d/" and "/usr/lib/update-notifier/" directories. These scripts run as the root user every time a user connects over SSH or a serial connection. Adversaries may create malicious MOTD files that grant them persistence onto the target every time a user connects to the system by executing a backdoor script or command. This rule detects the creation of potentially malicious files within the default MOTD file directories.

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7

Suspicious Process Spawned from MOTD Detected

Message of the day (MOTD) is the message that is presented to the user when a user connects to a Linux server via SSH or a serial connection. Linux systems contain several default MOTD files located in the "/etc/update-motd.d/" and "/usr/lib/update-notifier/" directories. These scripts run as the root user every time a user connects over SSH or a serial connection. Adversaries may create malicious MOTD files that grant them persistence onto the target every time a user connects to the system by executing a backdoor script or command. This rule detects the execution of potentially malicious processes through the MOTD utility.

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7

Potential Persistence Through Run Control Detected

This rule monitors the creation/alteration of the rc.local file by a previously unknown process executable through the use of the new terms rule type. The /etc/rc.local file is used to start custom applications, services, scripts or commands during start-up. The rc.local file has mostly been replaced by Systemd. However, through the "systemd-rc-local-generator", rc.local files can be converted to services that run at boot. Adversaries may alter rc.local to execute malicious code at start-up, and gain persistence onto the system.

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108

Setcap setuid/setgid Capability Set

This rule monitors for the addition of the cap_setuid+ep or cap_setgid+ep capabilities via setcap. Setuid (Set User ID) and setgid (Set Group ID) are Unix-like OS features that enable processes to run with elevated privileges, based on the file owner or group. Threat actors can exploit these attributes to achieve persistence by creating malicious binaries, allowing them to maintain control over a compromised system with elevated permissions.

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2

Shared Object Created or Changed by Previously Unknown Process

This rule monitors the creation of shared object files by previously unknown processes. The creation of a shared object file involves compiling code into a dynamically linked library that can be loaded by other programs at runtime. While this process is typically used for legitimate purposes, malicious actors can leverage shared object files to execute unauthorized code, inject malicious functionality into legitimate processes, or bypass security controls. This allows malware to persist on the system, evade detection, and potentially compromise the integrity and confidentiality of the affected system and its data.

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5

New Systemd Timer Created

Detects the creation of a systemd timer within any of the default systemd timer directories. Systemd timers can be used by an attacker to gain persistence, by scheduling the execution of a command or script. Similarly to cron/at, systemd timers can be set up to execute on boot time, or on a specific point in time, which allows attackers to regain access in case the connection to the infected asset was lost.

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7

New Systemd Service Created by Previously Unknown Process

Systemd service files are configuration files in Linux systems used to define and manage system services. Malicious actors can leverage systemd service files to achieve persistence by creating or modifying service files to execute malicious commands or payloads during system startup. This allows them to maintain unauthorized access, execute additional malicious activities, or evade detection.

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6

Potential Unauthorized Access via Wildcard Injection Detected

This rule monitors for the execution of the "chown" and "chmod" commands with command line flags that could indicate a wildcard injection attack. Linux wildcard injection is a type of security vulnerability where attackers manipulate commands or input containing wildcards (e.g., *, ?, []) to execute unintended operations or access sensitive data by tricking the system into interpreting the wildcard characters in unexpected ways.

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4

Potential Privilege Escalation via Container Misconfiguration

This rule monitors for the execution of processes that interact with Linux containers through an interactive shell without root permissions. Utilities such as runc and ctr are universal command-line utilities leveraged to interact with containers via root permissions. On systems where the access to these utilities are misconfigured, attackers might be able to create and run a container that mounts the root folder or spawn a privileged container vulnerable to a container escape attack, which might allow them to escalate privileges and gain further access onto the host file system.

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4

Modification of Dynamic Linker Preload Shared Object

Identifies modification of the dynamic linker preload shared object (ld.so.preload). Adversaries may execute malicious payloads by hijacking the dynamic linker used to load libraries.

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208

Suspicious Symbolic Link Created

Identifies the creation of a symbolic link to a suspicious file or location. A symbolic link is a reference to a file or directory that acts as a pointer or shortcut, allowing users to access the target file or directory from a different location in the file system. An attacker can potentially leverage symbolic links for privilege escalation by tricking a privileged process into following the symbolic link to a sensitive file, giving the attacker access to data or capabilities they would not normally have.

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4

Potential Privilege Escalation via UID INT_MAX Bug Detected

This rule monitors for the execution of the systemd-run command by a user with a UID that is larger than the maximum allowed UID size (INT_MAX). Some older Linux versions were affected by a bug which allows user accounts with a UID greater than INT_MAX to escalate privileges by spawning a shell through systemd-run.

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4

Kernel Load or Unload via Kexec Detected

This detection rule identifies the usage of kexec, helping to uncover unauthorized kernel replacements and potential compromise of the system’s integrity. Kexec is a Linux feature that enables the loading and execution of a different kernel without going through the typical boot process. Malicious actors can abuse kexec to bypass security measures, escalate privileges, establish persistence or hide their activities by loading a malicious kernel, enabling them to tamper with the system’s trusted state, allowing e.g. a VM Escape.

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5

Potential Privilege Escalation via CVE-2023-4911

This rule detects potential privilege escalation attempts through Looney Tunables (CVE-2023-4911). Looney Tunables is a buffer overflow vulnerability in GNU C Library’s dynamic loader’s processing of the GLIBC_TUNABLES environment variable.

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3

Potential Privilege Escalation via OverlayFS

Identifies an attempt to exploit a local privilege escalation (CVE-2023-2640 and CVE-2023-32629) via a flaw in Ubuntu’s modifications to OverlayFS. These flaws allow the creation of specialized executables, which, upon execution, grant the ability to escalate privileges to root on the affected machine.

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4

Potential Privilege Escalation via PKEXEC

Identifies an attempt to exploit a local privilege escalation in polkit pkexec (CVE-2021-4034) via unsecure environment variable injection. Successful exploitation allows an unprivileged user to escalate to the root user.

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107

Potential Shell via Wildcard Injection Detected

This rule monitors for the execution of a set of linux binaries, that are potentially vulnerable to wildcard injection, with suspicious command line flags followed by a shell spawn event. Linux wildcard injection is a type of security vulnerability where attackers manipulate commands or input containing wildcards (e.g., *, ?, []) to execute unintended operations or access sensitive data by tricking the system into interpreting the wildcard characters in unexpected ways.

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4

Potential Suspicious DebugFS Root Device Access

This rule monitors for the usage of the built-in Linux DebugFS utility to access a disk device without root permissions. Linux users that are part of the "disk" group have sufficient privileges to access all data inside of the machine through DebugFS. Attackers may leverage DebugFS in conjunction with "disk" permissions to read sensitive files owned by root, such as the shadow file, root ssh private keys or other sensitive files that may allow them to further escalate privileges.

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4

Potential Shadow File Read via Command Line Utilities

Identifies access to the /etc/shadow file via the commandline using standard system utilities. After elevating privileges to root, threat actors may attempt to read or dump this file in order to gain valid credentials. They may utilize these to move laterally undetected and access additional resources.

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108

Potential Sudo Privilege Escalation via CVE-2019-14287

This rule monitors for the execution of a suspicious sudo command that is leveraged in CVE-2019-14287 to escalate privileges to root. Sudo does not verify the presence of the designated user ID and proceeds to execute using a user ID that can be chosen arbitrarily. By using the sudo privileges, the command "sudo -u#-1" translates to an ID of 0, representing the root user. This exploit may work for sudo versions prior to v1.28.

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3

Potential Sudo Hijacking Detected

Identifies the creation of a sudo binary located at /usr/bin/sudo. Attackers may hijack the default sudo binary and replace it with a custom binary or script that can read the user’s password in clear text to escalate privileges or enable persistence onto the system every time the sudo binary is executed.

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104

Potential Sudo Token Manipulation via Process Injection

This rule detects potential sudo token manipulation attacks through process injection by monitoring the use of a debugger (gdb) process followed by a successful uid change event during the execution of the sudo process. A sudo token manipulation attack is performed by injecting into a process that has a valid sudo token, which can then be used by attackers to activate their own sudo token. This attack requires ptrace to be enabled in conjunction with the existence of a living process that has a valid sudo token with the same uid as the current user.

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4

Potential Privilege Escalation via Python cap_setuid

This detection rule monitors for the execution of a system command with setuid or setgid capabilities via Python, followed by a uid or gid change to the root user. This sequence of events may indicate successful privilege escalation. Setuid (Set User ID) and setgid (Set Group ID) are Unix-like OS features that enable processes to run with elevated privileges, based on the file owner or group. Threat actors can exploit these attributes to escalate privileges to the privileges that are set on the binary that is being executed.

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2

Potential Privilege Escalation via Recently Compiled Executable

This rule monitors a sequence involving a program compilation event followed by its execution and a subsequent alteration of UID permissions to root privileges. This behavior can potentially indicate the execution of a kernel or software privilege escalation exploit.

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3

Namespace Manipulation Using Unshare

Identifies suspicious usage of unshare to manipulate system namespaces. Unshare can be utilized to escalate privileges or escape container security boundaries. Threat actors have utilized this binary to allow themselves to escape to the host and access other resources or escalate privileges.

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8

Potential Privilege Escalation through Writable Docker Socket

This rule monitors for the usage of Docker runtime sockets to escalate privileges on Linux systems. Docker sockets by default are only be writable by the root user and docker group. Attackers that have permissions to write to these sockets may be able to create and run a container that allows them to escalate privileges and gain further access onto the host file system.

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4

Access of Stored Browser Credentials

Identifies the execution of a process with arguments pointing to known browser files that store passwords and cookies. Adversaries may acquire credentials from web browsers by reading files specific to the target browser.

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105

Access to Keychain Credentials Directories

Adversaries may collect the keychain storage data from a system to acquire credentials. Keychains are the built-in way for macOS to keep track of users' passwords and credentials for many services and features such as WiFi passwords, websites, secure notes and certificates.

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105

Dumping of Keychain Content via Security Command

Adversaries may dump the content of the keychain storage data from a system to acquire credentials. Keychains are the built-in way for macOS to keep track of users' passwords and credentials for many services and features, including Wi-Fi and website passwords, secure notes, certificates, and Kerberos.

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105

Keychain Password Retrieval via Command Line

Adversaries may collect keychain storage data from a system to in order to acquire credentials. Keychains are the built-in way for macOS to keep track of users' passwords and credentials for many services and features, including Wi-Fi and website passwords, secure notes, certificates, and Kerberos.

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105

Prompt for Credentials with OSASCRIPT

Identifies the use of osascript to execute scripts via standard input that may prompt a user with a rogue dialog for credentials.

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105

Attempt to Remove File Quarantine Attribute

Identifies a potential Gatekeeper bypass. In macOS, when applications or programs are downloaded from the internet, there is a quarantine flag set on the file. This attribute is read by Apple’s Gatekeeper defense program at execution time. An adversary may disable this attribute to evade defenses.

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105

Potential Privacy Control Bypass via TCCDB Modification

Identifies the use of sqlite3 to directly modify the Transparency, Consent, and Control (TCC) SQLite database. This may indicate an attempt to bypass macOS privacy controls, including access to sensitive resources like the system camera, microphone, address book, and calendar.

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105

Potential Privacy Control Bypass via Localhost Secure Copy

Identifies use of the Secure Copy Protocol (SCP) to copy files locally by abusing the auto addition of the Secure Shell Daemon (sshd) to the authorized application list for Full Disk Access. This may indicate attempts to bypass macOS privacy controls to access sensitive files.

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105

Enumeration of Users or Groups via Built-in Commands

Identifies the execution of macOS built-in commands related to account or group enumeration. Adversaries may use account and group information to orient themselves before deciding how to act.

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105

Attempt to Mount SMB Share via Command Line

Identifies the execution of macOS built-in commands to mount a Server Message Block (SMB) network share. Adversaries may use valid accounts to interact with a remote network share using SMB.

update

105

Virtual Private Network Connection Attempt

Identifies the execution of macOS built-in commands to connect to an existing Virtual Private Network (VPN). Adversaries may use VPN connections to laterally move and control remote systems on a network.

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105

Creation of Hidden Login Item via Apple Script

Identifies the execution of osascript to create a hidden login item. This may indicate an attempt to persist a malicious program while concealing its presence.

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106

Emond Rules Creation or Modification

Identifies the creation or modification of the Event Monitor Daemon (emond) rules. Adversaries may abuse this service by writing a rule to execute commands when a defined event occurs, such as system start up or user authentication.

update

105

Creation of Hidden Launch Agent or Daemon

Identifies the creation of a hidden launch agent or daemon. An adversary may establish persistence by installing a new launch agent or daemon which executes at login.

update

105

Persistence via Login or Logout Hook

Identifies use of the Defaults command to install a login or logoff hook in MacOS. An adversary may abuse this capability to establish persistence in an environment by inserting code to be executed at login or logout.

update

105

Sublime Plugin or Application Script Modification

Adversaries may create or modify the Sublime application plugins or scripts to execute a malicious payload each time the Sublime application is started.

update

105

Unexpected Child Process of macOS Screensaver Engine

Identifies when a child process is spawned by the screensaver engine process, which is consistent with an attacker’s malicious payload being executed after the screensaver activated on the endpoint. An adversary can maintain persistence on a macOS endpoint by creating a malicious screensaver (.saver) file and configuring the screensaver plist file to execute code each time the screensaver is activated.

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105

Screensaver Plist File Modified by Unexpected Process

Identifies when a screensaver plist file is modified by an unexpected process. An adversary can maintain persistence on a macOS endpoint by creating a malicious screensaver (.saver) file and configuring the screensaver plist file to execute code each time the screensaver is activated.

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105

Apple Scripting Execution with Administrator Privileges

Identifies execution of the Apple script interpreter (osascript) without a password prompt and with administrator privileges.

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105

Suspicious Inter-Process Communication via Outlook

Detects Inter-Process Communication with Outlook via Component Object Model from an unusual process. Adversaries may target user email to collect sensitive information or send email on their behalf via API.

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5

Exporting Exchange Mailbox via PowerShell

Identifies the use of the Exchange PowerShell cmdlet, New-MailBoxExportRequest, to export the contents of a primary mailbox or archive to a .pst file. Adversaries may target user email to collect sensitive information.

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109

PowerShell Suspicious Script with Audio Capture Capabilities

Detects PowerShell scripts that can record audio, a common feature in popular post-exploitation tooling.

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109

PowerShell Suspicious Script with Clipboard Retrieval Capabilities

Detects PowerShell scripts that can get the contents of the clipboard, which attackers can abuse to retrieve sensitive information like credentials, messages, etc.

update

7

PowerShell Keylogging Script

Detects the use of Win32 API Functions that can be used to capture user keystrokes in PowerShell scripts. Attackers use this technique to capture user input, looking for credentials and/or other valuable data.

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111

PowerShell Mailbox Collection Script

Detects PowerShell scripts that can be used to collect data from mailboxes. Adversaries may target user email to collect sensitive information.

update

6

PowerShell Suspicious Script with Screenshot Capabilities

Detects PowerShell scripts that can take screenshots, which is a common feature in post-exploitation kits and remote access tools (RATs).

update

107

Encrypting Files with WinRar or 7z

Identifies use of WinRar or 7z to create an encrypted files. Adversaries will often compress and encrypt data in preparation for exfiltration.

update

109

Connection to Commonly Abused Web Services

Adversaries may implement command and control (C2) communications that use common web services to hide their activity. This attack technique is typically targeted at an organization and uses web services common to the victim network, which allows the adversary to blend into legitimate traffic activity. These popular services are typically targeted since they have most likely been used before compromise, which helps malicious traffic blend in.

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109

Potential DNS Tunneling via NsLookup

This rule identifies a large number (15) of nslookup.exe executions with an explicit query type from the same host. This may indicate command and control activity utilizing the DNS protocol.

update

108

Connection to Commonly Abused Free SSL Certificate Providers

Identifies unusual processes connecting to domains using known free SSL certificates. Adversaries may employ a known encryption algorithm to conceal command and control traffic.

update

105

Ingress Transfer via Windows BITS

Identifies downloads of executable and archive files via the Windows Background Intelligent Transfer Service (BITS). Adversaries could leverage Windows BITS transfer jobs to download remote payloads.

update

5

Port Forwarding Rule Addition

Identifies the creation of a new port forwarding rule. An adversary may abuse this technique to bypass network segmentation restrictions.

update

108

Potential Remote Desktop Tunneling Detected

Identifies potential use of an SSH utility to establish RDP over a reverse SSH Tunnel. This can be used by attackers to enable routing of network packets that would otherwise not reach their intended destination.

update

108

Remote File Download via Desktopimgdownldr Utility

Identifies the desktopimgdownldr utility being used to download a remote file. An adversary may use desktopimgdownldr to download arbitrary files as an alternative to certutil.

update

108

Remote File Download via MpCmdRun

Identifies the Windows Defender configuration utility (MpCmdRun.exe) being used to download a remote file.

update

108

Remote File Download via PowerShell

Identifies powershell.exe being used to download an executable file from an untrusted remote destination.

update

108

Remote File Copy via TeamViewer

Identifies an executable or script file remotely downloaded via a TeamViewer transfer session.

update

108

Privileged Account Brute Force

Identifies multiple consecutive logon failures targeting an Admin account from the same source address and within a short time interval. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to accounts.

update

8

Multiple Logon Failure Followed by Logon Success

Identifies multiple logon failures followed by a successful one from the same source address. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to accounts.

update

8

Multiple Logon Failure from the same Source Address

Identifies multiple consecutive logon failures from the same source address and within a short time interval. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to accounts.

update

8

Potential Credential Access via Windows Utilities

Identifies the execution of known Windows utilities often abused to dump LSASS memory or the Active Directory database (NTDS.dit) in preparation for credential access.

update

110

NTDS or SAM Database File Copied

Identifies a copy operation of the Active Directory Domain Database (ntds.dit) or Security Account Manager (SAM) files. Those files contain sensitive information including hashed domain and/or local credentials.

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108

FirstTime Seen Account Performing DCSync

This rule identifies when a User Account starts the Active Directory Replication Process for the first time. Attackers can use the DCSync technique to get credential information of individual accounts or the entire domain, thus compromising the entire domain.

update

8

Potential Credential Access via DCSync

This rule identifies when a User Account starts the Active Directory Replication Process. Attackers can use the DCSync technique to get credential information of individual accounts or the entire domain, thus compromising the entire domain.

update

111

Kerberos Pre-authentication Disabled for User

Identifies the modification of an account’s Kerberos pre-authentication options. An adversary with GenericWrite/GenericAll rights over the account can maliciously modify these settings to perform offline password cracking attacks such as AS-REP roasting.

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109

Creation or Modification of Domain Backup DPAPI private key

Identifies the creation or modification of Domain Backup private keys. Adversaries may extract the Data Protection API (DPAPI) domain backup key from a Domain Controller (DC) to be able to decrypt any domain user master key file.

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106

Credential Acquisition via Registry Hive Dumping

Identifies attempts to export a registry hive which may contain credentials using the Windows reg.exe tool.

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107

Microsoft IIS Service Account Password Dumped

Identifies the Internet Information Services (IIS) command-line tool, AppCmd, being used to list passwords. An attacker with IIS web server access via a web shell can decrypt and dump the IIS AppPool service account password using AppCmd.

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107

Microsoft IIS Connection Strings Decryption

Identifies use of aspnet_regiis to decrypt Microsoft IIS connection strings. An attacker with Microsoft IIS web server access via a webshell or alike can decrypt and dump any hardcoded connection strings, such as the MSSQL service account password using aspnet_regiis command.

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107

Kerberos Traffic from Unusual Process

Identifies network connections to the standard Kerberos port from an unusual process. On Windows, the only process that normally performs Kerberos traffic from a domain joined host is lsass.exe.

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108

Access to a Sensitive LDAP Attribute

Identify access to sensitive Active Directory object attributes that contains credentials and decryption keys such as unixUserPassword, ms-PKI-AccountCredentials and msPKI-CredentialRoamingTokens.

update

9

Suspicious LSASS Access via MalSecLogon

Identifies suspicious access to LSASS handle from a call trace pointing to seclogon.dll and with a suspicious access rights value. This may indicate an attempt to leak an LSASS handle via abusing the Secondary Logon service in preparation for credential access.

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207

Suspicious Module Loaded by LSASS

Identifies LSASS loading an unsigned or untrusted DLL. Windows Security Support Provider (SSP) DLLs are loaded into LSSAS process at system start. Once loaded into the LSA, SSP DLLs have access to encrypted and plaintext passwords that are stored in Windows, such as any logged-on user’s Domain password or smart card PINs.

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5

LSASS Memory Dump Creation

Identifies the creation of a Local Security Authority Subsystem Service (lsass.exe) default memory dump. This may indicate a credential access attempt via trusted system utilities such as Task Manager (taskmgr.exe) and SQL Dumper (sqldumper.exe) or known pentesting tools such as Dumpert and AndrewSpecial.

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107

LSASS Memory Dump Handle Access

Identifies handle requests for the Local Security Authority Subsystem Service (LSASS) object access with specific access masks that many tools with a capability to dump memory to disk use (0x1fffff, 0x1010, 0x120089). This rule is tool agnostic as it has been validated against a host of various LSASS dump tools such as SharpDump, Procdump, Mimikatz, Comsvcs etc. It detects this behavior at a low level and does not depend on a specific tool or dump file name.

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109

LSASS Process Access via Windows API

Identifies access attempts to the LSASS handle, which may indicate an attempt to dump credentials from LSASS memory.

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5

Mimikatz Memssp Log File Detected

Identifies the password log file from the default Mimikatz memssp module.

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107

Potential Invoke-Mimikatz PowerShell Script

Mimikatz is a credential dumper capable of obtaining plaintext Windows account logins and passwords, along with many other features that make it useful for testing the security of networks. This rule detects Invoke-Mimikatz PowerShell script and alike.

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107

Modification of WDigest Security Provider

Identifies attempts to modify the WDigest security provider in the registry to force the user’s password to be stored in clear text in memory. This behavior can be indicative of an adversary attempting to weaken the security configuration of an endpoint. Once the UseLogonCredential value is modified, the adversary may attempt to dump clear text passwords from memory.

update

107

Windows Registry File Creation in SMB Share

Identifies the creation or modification of a medium-size registry hive file on a Server Message Block (SMB) share, which may indicate an exfiltration attempt of a previously dumped Security Account Manager (SAM) registry hive for credential extraction on an attacker-controlled system.

update

107

Network Logon Provider Registry Modification

Identifies the modification of the network logon provider registry. Adversaries may register a rogue network logon provider module for persistence and/or credential access via intercepting the authentication credentials in clear text during user logon.

update

106

PowerShell Kerberos Ticket Dump

Detects PowerShell scripts that have the capability of dumping Kerberos tickets from LSA, which potentially indicates an attacker’s attempt to acquire credentials for lateral movement.

update

2

PowerShell MiniDump Script

This rule detects PowerShell scripts capable of dumping process memory using WindowsErrorReporting or Dbghelp.dll MiniDumpWriteDump. Attackers can use this tooling to dump LSASS and get access to credentials.

update

107

PowerShell Kerberos Ticket Request

Detects PowerShell scripts that have the capability of requesting kerberos tickets, which is a common step in Kerberoasting toolkits to crack service accounts.

update

109

Potential Credential Access via DuplicateHandle in LSASS

Identifies suspicious access to an LSASS handle via DuplicateHandle from an unknown call trace module. This may indicate an attempt to bypass the NtOpenProcess API to evade detection and dump LSASS memory for credential access.

update

207

Potential Remote Credential Access via Registry

Identifies remote access to the registry to potentially dump credential data from the Security Account Manager (SAM) registry hive in preparation for credential access and privileges elevation.

update

109

Multiple Vault Web Credentials Read

Windows Credential Manager allows you to create, view, or delete saved credentials for signing into websites, connected applications, and networks. An adversary may abuse this to list or dump credentials stored in the Credential Manager for saved usernames and passwords. This may also be performed in preparation of lateral movement.

update

9

Searching for Saved Credentials via VaultCmd

Windows Credential Manager allows you to create, view, or delete saved credentials for signing into websites, connected applications, and networks. An adversary may abuse this to list or dump credentials stored in the Credential Manager for saved usernames and passwords. This may also be performed in preparation of lateral movement.

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107

Sensitive Privilege SeEnableDelegationPrivilege assigned to a User

Identifies the assignment of the SeEnableDelegationPrivilege sensitive "user right" to a user. The SeEnableDelegationPrivilege "user right" enables computer and user accounts to be trusted for delegation. Attackers can abuse this right to compromise Active Directory accounts and elevate their privileges.

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109

Potential Shadow Credentials added to AD Object

Identify the modification of the msDS-KeyCredentialLink attribute in an Active Directory Computer or User Object. Attackers can abuse control over the object and create a key pair, append to raw public key in the attribute, and obtain persistent and stealthy access to the target user or computer object.

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107

User account exposed to Kerberoasting

Detects when a user account has the servicePrincipalName attribute modified. Attackers can abuse write privileges over a user to configure Service Principle Names (SPNs) so that they can perform Kerberoasting. Administrators can also configure this for legitimate purposes, exposing the account to Kerberoasting.

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108

Potential Credential Access via Renamed COM+ Services DLL

Identifies suspicious renamed COMSVCS.DLL Image Load, which exports the MiniDump function that can be used to dump a process memory. This may indicate an attempt to dump LSASS memory while bypassing command-line based detection in preparation for credential access.

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106

Suspicious Lsass Process Access

Identifies access attempts to LSASS handle, this may indicate an attempt to dump credentials from Lsass memory.

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106

Potential Credential Access via LSASS Memory Dump

Identifies suspicious access to LSASS handle from a call trace pointing to DBGHelp.dll or DBGCore.dll, which both export the MiniDumpWriteDump method that can be used to dump LSASS memory content in preparation for credential access.

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208

Potential LSASS Memory Dump via PssCaptureSnapShot

Identifies suspicious access to an LSASS handle via PssCaptureSnapShot where two successive process accesses are performed by the same process and target two different instances of LSASS. This may indicate an attempt to evade detection and dump LSASS memory for credential access.

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207

Suspicious Remote Registry Access via SeBackupPrivilege

Identifies remote access to the registry using an account with Backup Operators group membership. This may indicate an attempt to exfiltrate credentials by dumping the Security Account Manager (SAM) registry hive in preparation for credential access and privileges elevation.

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109

Symbolic Link to Shadow Copy Created

Identifies the creation of symbolic links to a shadow copy. Symbolic links can be used to access files in the shadow copy, including sensitive files such as ntds.dit, System Boot Key and browser offline credentials.

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108

Potential LSASS Clone Creation via PssCaptureSnapShot

Identifies the creation of an LSASS process clone via PssCaptureSnapShot where the parent process is the initial LSASS process instance. This may indicate an attempt to evade detection and dump LSASS memory for credential access.

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105

Modification of AmsiEnable Registry Key

Identifies modifications of the AmsiEnable registry key to 0, which disables the Antimalware Scan Interface (AMSI). An adversary can modify this key to disable AMSI protections.

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108

Clearing Windows Console History

Identifies when a user attempts to clear console history. An adversary may clear the command history of a compromised account to conceal the actions undertaken during an intrusion.

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108

Clearing Windows Event Logs

Identifies attempts to clear or disable Windows event log stores using Windows wevetutil command. This is often done by attackers in an attempt to evade detection or destroy forensic evidence on a system.

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109

Creation or Modification of Root Certificate

Identifies the creation or modification of a local trusted root certificate in Windows. The install of a malicious root certificate would allow an attacker the ability to masquerade malicious files as valid signed components from any entity (for example, Microsoft). It could also allow an attacker to decrypt SSL traffic.

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107

Windows Defender Disabled via Registry Modification

Identifies modifications to the Windows Defender registry settings to disable the service or set the service to be started manually.

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108

Windows Defender Exclusions Added via PowerShell

Identifies modifications to the Windows Defender configuration settings using PowerShell to add exclusions at the folder directory or process level.

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107

Disable Windows Firewall Rules via Netsh

Identifies use of the netsh.exe to disable or weaken the local firewall. Attackers will use this command line tool to disable the firewall during troubleshooting or to enable network mobility.

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107

Disabling Windows Defender Security Settings via PowerShell

Identifies use of the Set-MpPreference PowerShell command to disable or weaken certain Windows Defender settings.

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108

Disable Windows Event and Security Logs Using Built-in Tools

Identifies attempts to disable EventLog via the logman Windows utility, PowerShell, or auditpol. This is often done by attackers in an attempt to evade detection on a system.

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109

DNS-over-HTTPS Enabled via Registry

Identifies when a user enables DNS-over-HTTPS. This can be used to hide internet activity or the process of exfiltrating data. With this enabled, an organization will lose visibility into data such as query type, response, and originating IP, which are used to determine bad actors.

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107

Suspicious .NET Code Compilation

Identifies executions of .NET compilers with suspicious parent processes, which can indicate an attacker’s attempt to compile code after delivery in order to bypass security mechanisms.

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108

Remote Desktop Enabled in Windows Firewall by Netsh

Identifies use of the network shell utility (netsh.exe) to enable inbound Remote Desktop Protocol (RDP) connections in the Windows Firewall.

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107

Enable Host Network Discovery via Netsh

Identifies use of the netsh.exe program to enable host discovery via the network. Attackers can use this command-line tool to weaken the host firewall settings.

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107

Control Panel Process with Unusual Arguments

Identifies unusual instances of Control Panel with suspicious keywords or paths in the process command line value. Adversaries may abuse control.exe to proxy execution of malicious code.

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108

ImageLoad via Windows Update Auto Update Client

Identifies abuse of the Windows Update Auto Update Client (wuauclt.exe) to load an arbitrary DLL. This behavior is used as a defense evasion technique to blend-in malicious activity with legitimate Windows software.

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108

Microsoft Build Engine Started by an Office Application

An instance of MSBuild, the Microsoft Build Engine, was started by Excel or Word. This is unusual behavior for the Build Engine and could have been caused by an Excel or Word document executing a malicious script payload.

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108

Microsoft Build Engine Started by a Script Process

An instance of MSBuild, the Microsoft Build Engine, was started by a script or the Windows command interpreter. This behavior is unusual and is sometimes used by malicious payloads.

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207

Microsoft Build Engine Started by a System Process

An instance of MSBuild, the Microsoft Build Engine, was started by Explorer or the WMI (Windows Management Instrumentation) subsystem. This behavior is unusual and is sometimes used by malicious payloads.

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108

Microsoft Build Engine Using an Alternate Name

An instance of MSBuild, the Microsoft Build Engine, was started after being renamed. This is uncommon behavior and may indicate an attempt to run unnoticed or undetected.

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110

Microsoft Build Engine Started an Unusual Process

An instance of MSBuild, the Microsoft Build Engine, started a PowerShell script or the Visual C# Command Line Compiler. This technique is sometimes used to deploy a malicious payload using the Build Engine.

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208

Potential DLL Side-Loading via Trusted Microsoft Programs

Identifies an instance of a Windows trusted program that is known to be vulnerable to DLL Search Order Hijacking starting after being renamed or from a non-standard path. This is uncommon behavior and may indicate an attempt to evade defenses via side loading a malicious DLL within the memory space of one of those processes.

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108

Potential DLL Side-Loading via Microsoft Antimalware Service Executable

Identifies a Windows trusted program that is known to be vulnerable to DLL Search Order Hijacking starting after being renamed or from a non-standard path. This is uncommon behavior and may indicate an attempt to evade defenses via side-loading a malicious DLL within the memory space of one of those processes.

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108

Executable File Creation with Multiple Extensions

Masquerading can allow an adversary to evade defenses and better blend in with the environment. One way it occurs is when the name or location of a file is manipulated as a means of tricking a user into executing what they think is a benign file type but is actually executable code.

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106

Process Execution from an Unusual Directory

Identifies process execution from suspicious default Windows directories. This is sometimes done by adversaries to hide malware in trusted paths.

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107

IIS HTTP Logging Disabled

Identifies when Internet Information Services (IIS) HTTP Logging is disabled on a server. An attacker with IIS server access via a webshell or other mechanism can disable HTTP Logging as an effective anti-forensics measure.

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107

Suspicious Endpoint Security Parent Process

A suspicious Endpoint Security parent process was detected. This may indicate a process hollowing or other form of code injection.

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108

Renamed AutoIt Scripts Interpreter

Identifies a suspicious AutoIt process execution. Malware written as an AutoIt script tends to rename the AutoIt executable to avoid detection.

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108

Suspicious WerFault Child Process

A suspicious WerFault child process was detected, which may indicate an attempt to run via the SilentProcessExit registry key manipulation. Verify process details such as command line, network connections and file writes.

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109

Program Files Directory Masquerading

Identifies execution from a directory masquerading as the Windows Program Files directories. These paths are trusted and usually host trusted third party programs. An adversary may leverage masquerading, along with low privileges to bypass detections allowlisting those folders.

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106

Microsoft Windows Defender Tampering

Identifies when one or more features on Microsoft Defender are disabled. Adversaries may disable or tamper with Microsoft Defender features to evade detection and conceal malicious behavior.

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108

MS Office Macro Security Registry Modifications

Microsoft Office Products offer options for users and developers to control the security settings for running and using Macros. Adversaries may abuse these security settings to modify the default behavior of the Office Application to trust future macros and/or disable security warnings, which could increase their chances of establishing persistence.

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106

Suspicious .NET Reflection via PowerShell

Detects the use of Reflection.Assembly to load PEs and DLLs in memory in PowerShell scripts. Attackers use this method to load executables and DLLs without writing to the disk, bypassing security solutions.

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110

PowerShell Suspicious Payload Encoded and Compressed

Identifies the use of .NET functionality for decompression and base64 decoding combined in PowerShell scripts, which malware and security tools heavily use to deobfuscate payloads and load them directly in memory to bypass defenses.

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110

Potential Process Injection via PowerShell

Detects the use of Windows API functions that are commonly abused by malware and security tools to load malicious code or inject it into remote processes.

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109

Windows Firewall Disabled via PowerShell

Identifies when the Windows Firewall is disabled using PowerShell cmdlets, which can help attackers evade network constraints, like internet and network lateral communication restrictions.

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108

Suspicious Microsoft Diagnostics Wizard Execution

Identifies potential abuse of the Microsoft Diagnostics Troubleshooting Wizard (MSDT) to proxy malicious command or binary execution via malicious process arguments.

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107

Scheduled Tasks AT Command Enabled

Identifies attempts to enable the Windows scheduled tasks AT command via the registry. Attackers may use this method to move laterally or persist locally. The AT command has been deprecated since Windows 8 and Windows Server 2012, but still exists for backwards compatibility.

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107

SolarWinds Process Disabling Services via Registry

Identifies a SolarWinds binary modifying the start type of a service to be disabled. An adversary may abuse this technique to manipulate relevant security services.

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107

Suspicious Execution from a Mounted Device

Identifies when a script interpreter or signed binary is launched via a non-standard working directory. An attacker may use this technique to evade defenses.

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106

Suspicious Process Access via Direct System Call

Identifies suspicious process access events from an unknown memory region. Endpoint security solutions usually hook userland Windows APIs in order to decide if the code that is being executed is malicious or not. It’s possible to bypass hooked functions by writing malicious functions that call syscalls directly.

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210

Unusual Executable File Creation by a System Critical Process

Identifies an unexpected executable file being created or modified by a Windows system critical process, which may indicate activity related to remote code execution or other forms of exploitation.

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109

Unsigned DLL Side-Loading from a Suspicious Folder

Identifies a Windows trusted program running from locations often abused by adversaries to masquerade as a trusted program and loading a recently dropped DLL. This behavior may indicate an attempt to evade defenses via side-loading a malicious DLL within the memory space of a signed processes.

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6

Unusual File Creation - Alternate Data Stream

Identifies suspicious creation of Alternate Data Streams on highly targeted files. This is uncommon for legitimate files and sometimes done by adversaries to hide malware.

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112

Unusual Process Execution Path - Alternate Data Stream

Identifies processes running from an Alternate Data Stream. This is uncommon for legitimate processes and sometimes done by adversaries to hide malware.

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106

Unusual Child Process from a System Virtual Process

Identifies a suspicious child process of the Windows virtual system process, which could indicate code injection.

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107

Signed Proxy Execution via MS Work Folders

Identifies the use of Windows Work Folders to execute a potentially masqueraded control.exe file in the current working directory. Misuse of Windows Work Folders could indicate malicious activity.

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106

AdFind Command Activity

This rule detects the Active Directory query tool, AdFind.exe. AdFind has legitimate purposes, but it is frequently leveraged by threat actors to perform post-exploitation Active Directory reconnaissance. The AdFind tool has been observed in Trickbot, Ryuk, Maze, and FIN6 campaigns. For Winlogbeat, this rule requires Sysmon.

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108

Enumeration of Administrator Accounts

Identifies instances of lower privilege accounts enumerating Administrator accounts or groups using built-in Windows tools.

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109

Account Discovery Command via SYSTEM Account

Identifies when the SYSTEM account uses an account discovery utility. This could be a sign of discovery activity after an adversary has achieved privilege escalation.

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108

Peripheral Device Discovery

Identifies use of the Windows file system utility (fsutil.exe) to gather information about attached peripheral devices and components connected to a computer system.

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107

PowerShell Share Enumeration Script

Detects scripts that contain PowerShell functions, structures, or Windows API functions related to windows share enumeration activities. Attackers, mainly ransomware groups, commonly identify and inspect network shares, looking for critical information for encryption and/or exfiltration.

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8

PowerShell Suspicious Discovery Related Windows API Functions

This rule detects the use of discovery-related Windows API functions in PowerShell Scripts. Attackers can use these functions to perform various situational awareness related activities, like enumerating users, shares, sessions, domain trusts, groups, etc.

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111

Enumeration of Privileged Local Groups Membership

Identifies instances of an unusual process enumerating built-in Windows privileged local groups membership like Administrators or Remote Desktop users.

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209

Whoami Process Activity

Identifies suspicious use of whoami.exe which displays user, group, and privileges information for the user who is currently logged on to the local system.

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108

Command Execution via SolarWinds Process

A suspicious SolarWinds child process (Cmd.exe or Powershell.exe) was detected.

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108

Suspicious SolarWinds Child Process

A suspicious SolarWinds child process was detected, which may indicate an attempt to execute malicious programs.

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107

Execution of COM object via Xwizard

Windows Component Object Model (COM) is an inter-process communication (IPC) component of the native Windows application programming interface (API) that enables interaction between software objects or executable code. Xwizard can be used to run a COM object created in registry to evade defensive counter measures.

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107

Svchost spawning Cmd

Identifies a suspicious parent child process relationship with cmd.exe descending from svchost.exe

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208

Unusual Parent Process for cmd.exe

Identifies a suspicious parent child process relationship with cmd.exe descending from an unusual process.

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108

Command Shell Activity Started via RunDLL32

Identifies command shell activity started via RunDLL32, which is commonly abused by attackers to host malicious code.

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108

Enumeration Command Spawned via WMIPrvSE

Identifies native Windows host and network enumeration commands spawned by the Windows Management Instrumentation Provider Service (WMIPrvSE).

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108

Execution from Unusual Directory - Command Line

Identifies process execution from suspicious default Windows directories. This may be abused by adversaries to hide malware in trusted paths.

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109

Potential PowerShell HackTool Script by Function Names

Detects known PowerShell offensive tooling functions names in PowerShell scripts. Attackers commonly use out-of-the-box offensive tools without modifying the code. This rule aim is to take advantage of that.

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7

Suspicious Portable Executable Encoded in Powershell Script

Detects the presence of a portable executable (PE) in a PowerShell script by looking for its encoded header. Attackers embed PEs into PowerShell scripts to inject them into memory, avoiding defences by not writing to disk.

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109

PowerShell PSReflect Script

Detects the use of PSReflect in PowerShell scripts. Attackers leverage PSReflect as a library that enables PowerShell to access win32 API functions.

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109

Execution via local SxS Shared Module

Identifies the creation, change, or deletion of a DLL module within a Windows SxS local folder. Adversaries may abuse shared modules to execute malicious payloads by instructing the Windows module loader to load DLLs from arbitrary local paths.

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106

Suspicious Cmd Execution via WMI

Identifies suspicious command execution (cmd) via Windows Management Instrumentation (WMI) on a remote host. This could be indicative of adversary lateral movement.

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108

Suspicious WMI Image Load from MS Office

Identifies a suspicious image load (wmiutils.dll) from Microsoft Office processes. This behavior may indicate adversarial activity where child processes are spawned via Windows Management Instrumentation (WMI). This technique can be used to execute code and evade traditional parent/child processes spawned from Microsoft Office products.

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106

Suspicious PDF Reader Child Process

Identifies suspicious child processes of PDF reader applications. These child processes are often launched via exploitation of PDF applications or social engineering.

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108

Suspicious Process Execution via Renamed PsExec Executable

Identifies suspicious psexec activity which is executing from the psexec service that has been renamed, possibly to evade detection.

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109

Process Activity via Compiled HTML File

Compiled HTML files (.chm) are commonly distributed as part of the Microsoft HTML Help system. Adversaries may conceal malicious code in a CHM file and deliver it to a victim for execution. CHM content is loaded by the HTML Help executable program (hh.exe).

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108

Conhost Spawned By Suspicious Parent Process

Detects when the Console Window Host (conhost.exe) process is spawned by a suspicious parent process, which could be indicative of code injection.

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108

Third-party Backup Files Deleted via Unexpected Process

Identifies the deletion of backup files, saved using third-party software, by a process outside of the backup suite. Adversaries may delete Backup files to ensure that recovery from a ransomware attack is less likely.

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109

Deleting Backup Catalogs with Wbadmin

Identifies use of the wbadmin.exe to delete the backup catalog. Ransomware and other malware may do this to prevent system recovery.

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108

Modification of Boot Configuration

Identifies use of bcdedit.exe to delete boot configuration data. This tactic is sometimes used as by malware or an attacker as a destructive technique.

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107

Volume Shadow Copy Deleted or Resized via VssAdmin

Identifies use of vssadmin.exe for shadow copy deletion or resizing on endpoints. This commonly occurs in tandem with ransomware or other destructive attacks.

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108

Volume Shadow Copy Deletion via PowerShell

Identifies the use of the Win32_ShadowCopy class and related cmdlets to achieve shadow copy deletion. This commonly occurs in tandem with ransomware or other destructive attacks.

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108

Volume Shadow Copy Deletion via WMIC

Identifies use of wmic.exe for shadow copy deletion on endpoints. This commonly occurs in tandem with ransomware or other destructive attacks.

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108

Suspicious HTML File Creation

Identifies the execution of a browser process to open an HTML file with high entropy and size. Adversaries may smuggle data and files past content filters by hiding malicious payloads inside of seemingly benign HTML files.

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105

Windows Script Executing PowerShell

Identifies a PowerShell process launched by either cscript.exe or wscript.exe. Observing Windows scripting processes executing a PowerShell script, may be indicative of malicious activity.

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108

Microsoft Exchange Server UM Writing Suspicious Files

Identifies suspicious files being written by the Microsoft Exchange Server Unified Messaging (UM) service. This activity has been observed exploiting CVE-2021-26858.

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106

Microsoft Exchange Server UM Spawning Suspicious Processes

Identifies suspicious processes being spawned by the Microsoft Exchange Server Unified Messaging (UM) service. This activity has been observed exploiting CVE-2021-26857.

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106

Microsoft Exchange Worker Spawning Suspicious Processes

Identifies suspicious processes being spawned by the Microsoft Exchange Server worker process (w3wp). This activity may indicate exploitation activity or access to an existing web shell backdoor.

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106

Suspicious MS Office Child Process

Identifies suspicious child processes of frequently targeted Microsoft Office applications (Word, PowerPoint, Excel). These child processes are often launched during exploitation of Office applications or from documents with malicious macros.

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109

Suspicious MS Outlook Child Process

Identifies suspicious child processes of Microsoft Outlook. These child processes are often associated with spear phishing activity.

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108

Suspicious Explorer Child Process

Identifies a suspicious Windows explorer child process. Explorer.exe can be abused to launch malicious scripts or executables from a trusted parent process.

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107

Potential Remote Desktop Shadowing Activity

Identifies the modification of the Remote Desktop Protocol (RDP) Shadow registry or the execution of processes indicative of an active RDP shadowing session. An adversary may abuse the RDP Shadowing feature to spy on or control other users active RDP sessions.

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107

Execution via TSClient Mountpoint

Identifies execution from the Remote Desktop Protocol (RDP) shared mountpoint tsclient on the target host. This may indicate a lateral movement attempt.

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107

Mounting Hidden or WebDav Remote Shares

Identifies the use of net.exe to mount a WebDav or hidden remote share. This may indicate lateral movement or preparation for data exfiltration.

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107

RDP Enabled via Registry

Identifies registry write modifications to enable Remote Desktop Protocol (RDP) access. This could be indicative of adversary lateral movement preparation.

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109

Remote File Copy to a Hidden Share

Identifies a remote file copy attempt to a hidden network share. This may indicate lateral movement or data staging activity.

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106

Suspicious RDP ActiveX Client Loaded

Identifies suspicious Image Loading of the Remote Desktop Services ActiveX Client (mstscax), this may indicate the presence of RDP lateral movement capability.

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106

Unusual Child Process of dns.exe

Identifies an unexpected process spawning from dns.exe, the process responsible for Windows DNS server services, which may indicate activity related to remote code execution or other forms of exploitation.

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108

Unusual File Modification by dns.exe

Identifies an unexpected file being modified by dns.exe, the process responsible for Windows DNS Server services, which may indicate activity related to remote code execution or other forms of exploitation.

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108

Lateral Movement via Startup Folder

Identifies suspicious file creations in the startup folder of a remote system. An adversary could abuse this to move laterally by dropping a malicious script or executable that will be executed after a reboot or user logon.

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106

Adobe Hijack Persistence

Detects writing executable files that will be automatically launched by Adobe on launch.

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109

Registry Persistence via AppCert DLL

Detects attempts to maintain persistence by creating registry keys using AppCert DLLs. AppCert DLLs are loaded by every process using the common API functions to create processes.

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106

Registry Persistence via AppInit DLL

AppInit DLLs are dynamic-link libraries (DLLs) that are loaded into every process that creates a user interface (loads user32.dll) on Microsoft Windows operating systems. The AppInit DLL mechanism is used to load custom code into user-mode processes, allowing for the customization of the user interface and the behavior of Windows-based applications. Attackers who add those DLLs to the registry locations can execute code with elevated privileges, similar to process injection, and provide a solid and constant persistence on the machine.

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107

Creation of a Hidden Local User Account

Identifies the creation of a hidden local user account by appending the dollar sign to the account name. This is sometimes done by attackers to increase access to a system and avoid appearing in the results of accounts listing using the net users command.

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107

Persistence via Scheduled Job Creation

A job can be used to schedule programs or scripts to be executed at a specified date and time. Adversaries may abuse task scheduling functionality to facilitate initial or recurring execution of malicious code.

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105

Persistence via Microsoft Office AddIns

Detects attempts to establish persistence on an endpoint by abusing Microsoft Office add-ins.

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106

Persistence via Microsoft Outlook VBA

Detects attempts to establish persistence on an endpoint by installing a rogue Microsoft Outlook VBA Template.

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105

KRBTGT Delegation Backdoor

Identifies the modification of the msDS-AllowedToDelegateTo attribute to KRBTGT. Attackers can use this technique to maintain persistence to the domain by having the ability to request tickets for the KRBTGT service.

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106

New ActiveSyncAllowedDeviceID Added via PowerShell

Identifies the use of the Exchange PowerShell cmdlet, Set-CASMailbox, to add a new ActiveSync allowed device. Adversaries may target user email to collect sensitive information.

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107

Potential Modification of Accessibility Binaries

Windows contains accessibility features that may be launched with a key combination before a user has logged in. An adversary can modify the way these programs are launched to get a command prompt or backdoor without logging in to the system.

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108

AdminSDHolder SDProp Exclusion Added

Identifies a modification on the dsHeuristics attribute on the bit that holds the configuration of groups excluded from the SDProp process. The SDProp compares the permissions on protected objects with those defined on the AdminSDHolder object. If the permissions on any of the protected accounts and groups do not match, the permissions on the protected accounts and groups are reset to match those of the domain’s AdminSDHolder object, meaning that groups excluded will remain unchanged. Attackers can abuse this misconfiguration to maintain long-term access to privileged accounts in these groups.

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109

Startup Persistence by a Suspicious Process

Identifies files written to or modified in the startup folder by commonly abused processes. Adversaries may use this technique to maintain persistence.

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108

Persistent Scripts in the Startup Directory

Identifies script engines creating files in the Startup folder, or the creation of script files in the Startup folder. Adversaries may abuse this technique to maintain persistence in an environment.

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109

Component Object Model Hijacking

Identifies Component Object Model (COM) hijacking via registry modification. Adversaries may establish persistence by executing malicious content triggered by hijacked references to COM objects.

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109

Suspicious Image Load (taskschd.dll) from MS Office

Identifies a suspicious image load (taskschd.dll) from Microsoft Office processes. This behavior may indicate adversarial activity where a scheduled task is configured via Windows Component Object Model (COM). This technique can be used to configure persistence and evade monitoring by avoiding the usage of the traditional Windows binary (schtasks.exe) used to manage scheduled tasks.

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106

Suspicious Execution via Scheduled Task

Identifies execution of a suspicious program via scheduled tasks by looking at process lineage and command line usage.

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106

User Added to Privileged Group

Identifies a user being added to a privileged group in Active Directory. Privileged accounts and groups in Active Directory are those to which powerful rights, privileges, and permissions are granted that allow them to perform nearly any action in Active Directory and on domain-joined systems.

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108

User Account Creation

Identifies attempts to create new users. This is sometimes done by attackers to increase access or establish persistence on a system or domain.

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107

Potential Application Shimming via Sdbinst

The Application Shim was created to allow for backward compatibility of software as the operating system codebase changes over time. This Windows functionality has been abused by attackers to stealthily gain persistence and arbitrary code execution in legitimate Windows processes.

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107

Persistence via BITS Job Notify Cmdline

An adversary can use the Background Intelligent Transfer Service (BITS) SetNotifyCmdLine method to execute a program that runs after a job finishes transferring data or after a job enters a specified state in order to persist on a system.

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105

Persistence via Hidden Run Key Detected

Identifies a persistence mechanism that utilizes the NtSetValueKey native API to create a hidden (null terminated) registry key. An adversary may use this method to hide from system utilities such as the Registry Editor (regedit).

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106

Installation of Security Support Provider

Identifies registry modifications related to the Windows Security Support Provider (SSP) configuration. Adversaries may abuse this to establish persistence in an environment.

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106

Persistence via TelemetryController Scheduled Task Hijack

Detects the successful hijack of Microsoft Compatibility Appraiser scheduled task to establish persistence with an integrity level of system.

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107

Persistence via Update Orchestrator Service Hijack

Identifies potential hijacking of the Microsoft Update Orchestrator Service to establish persistence with an integrity level of SYSTEM.

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109

Persistence via WMI Event Subscription

An adversary can use Windows Management Instrumentation (WMI) to install event filters, providers, consumers, and bindings that execute code when a defined event occurs. Adversaries may use the capabilities of WMI to subscribe to an event and execute arbitrary code when that event occurs, providing persistence on a system.

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108

Execution via MSSQL xp_cmdshell Stored Procedure

Identifies execution via MSSQL xp_cmdshell stored procedure. Malicious users may attempt to elevate their privileges by using xp_cmdshell, which is disabled by default, thus, it’s important to review the context of it’s use.

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108

Web Shell Detection: Script Process Child of Common Web Processes

Identifies suspicious commands executed via a web server, which may suggest a vulnerability and remote shell access.

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108

Process Creation via Secondary Logon

Identifies process creation with alternate credentials. Adversaries may create a new process with a different token to escalate privileges and bypass access controls.

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8

Modification of the msPKIAccountCredentials

Identify the modification of the msPKIAccountCredentials attribute in an Active Directory User Object. Attackers can abuse the credentials roaming feature to overwrite an arbitrary file for privilege escalation. ms-PKI-AccountCredentials contains binary large objects (BLOBs) of encrypted credential objects from the credential manager store, private keys, certificates, and certificate requests.

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8

Disabling User Account Control via Registry Modification

User Account Control (UAC) can help mitigate the impact of malware on Windows hosts. With UAC, apps and tasks always run in the security context of a non-administrator account, unless an administrator specifically authorizes administrator-level access to the system. This rule identifies registry value changes to bypass User Access Control (UAC) protection.

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108

Creation or Modification of a new GPO Scheduled Task or Service

Detects the creation or modification of a new Group Policy based scheduled task or service. These methods are used for legitimate system administration, but can also be abused by an attacker with domain admin permissions to execute a malicious payload remotely on all or a subset of the domain joined machines.

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107

Startup/Logon Script added to Group Policy Object

Detects the modification of Group Policy Objects (GPO) to add a startup/logon script to users or computer objects.

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108

Group Policy Abuse for Privilege Addition

Detects the first occurrence of a modification to Group Policy Object Attributes to add privileges to user accounts or use them to add users as local admins.

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108

Scheduled Task Execution at Scale via GPO

Detects the modification of Group Policy Object attributes to execute a scheduled task in the objects controlled by the GPO.

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109

Potential Privilege Escalation via InstallerFileTakeOver

Identifies a potential exploitation of InstallerTakeOver (CVE-2021-41379) default PoC execution. Successful exploitation allows an unprivileged user to escalate privileges to SYSTEM.

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109

Privilege Escalation via Named Pipe Impersonation

Identifies a privilege escalation attempt via named pipe impersonation. An adversary may abuse this technique by utilizing a framework such Metasploit’s meterpreter getsystem command.

update

107

Suspicious DLL Loaded for Persistence or Privilege Escalation

Identifies the loading of a non Microsoft signed DLL that is missing on a default Windows install (phantom DLL) or one that can be loaded from a different location by a native Windows process. This may be abused to persist or elevate privileges via privileged file write vulnerabilities.

update

109

PowerShell Script with Token Impersonation Capabilities

Detects scripts that contain PowerShell functions, structures, or Windows API functions related to token impersonation/theft. Attackers may duplicate then impersonate another user’s token to escalate privileges and bypass access controls.

update

9

Suspicious PrintSpooler Service Executable File Creation

Detects attempts to exploit privilege escalation vulnerabilities related to the Print Spooler service. For more information refer to the following CVE’s - CVE-2020-1048, CVE-2020-1337 and CVE-2020-1300 and verify that the impacted system is patched.

update

105

Suspicious Print Spooler File Deletion

Detects deletion of print driver files by an unusual process. This may indicate a clean up attempt post successful privilege escalation via Print Spooler service related vulnerabilities.

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105

Suspicious Print Spooler SPL File Created

Detects attempts to exploit privilege escalation vulnerabilities related to the Print Spooler service including CVE-2020-1048 and CVE-2020-1337.

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108

Potential Privileged Escalation via SamAccountName Spoofing

Identifies a suspicious computer account name rename event, which may indicate an attempt to exploit CVE-2021-42278 to elevate privileges from a standard domain user to a user with domain admin privileges. CVE-2021-42278 is a security vulnerability that allows potential attackers to impersonate a domain controller via samAccountName attribute spoofing.

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107

SeDebugPrivilege Enabled by a Suspicious Process

Identifies the creation of a process running as SYSTEM and impersonating a Windows core binary privileges. Adversaries may create a new process with a different token to escalate privileges and bypass access controls.

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5

UAC Bypass Attempt with IEditionUpgradeManager Elevated COM Interface

Identifies attempts to bypass User Account Control (UAC) by abusing an elevated COM Interface to launch a rogue Windows ClipUp program. Attackers may attempt to bypass UAC to stealthily execute code with elevated permissions.

update

107

UAC Bypass Attempt via Elevated COM Internet Explorer Add-On Installer

Identifies User Account Control (UAC) bypass attempts by abusing an elevated COM Interface to launch a malicious program. Attackers may attempt to bypass UAC to stealthily execute code with elevated permissions.

update

107

UAC Bypass via ICMLuaUtil Elevated COM Interface

Identifies User Account Control (UAC) bypass attempts via the ICMLuaUtil Elevated COM interface. Attackers may attempt to bypass UAC to stealthily execute code with elevated permissions.

update

107

UAC Bypass via DiskCleanup Scheduled Task Hijack

Identifies User Account Control (UAC) bypass via hijacking DiskCleanup Scheduled Task. Attackers bypass UAC to stealthily execute code with elevated permissions.

update

106

UAC Bypass Attempt via Privileged IFileOperation COM Interface

Identifies attempts to bypass User Account Control (UAC) via DLL side-loading. Attackers may attempt to bypass UAC to stealthily execute code with elevated permissions.

update

107

Bypass UAC via Event Viewer

Identifies User Account Control (UAC) bypass via eventvwr.exe. Attackers bypass UAC to stealthily execute code with elevated permissions.

update

109

UAC Bypass Attempt via Windows Directory Masquerading

Identifies an attempt to bypass User Account Control (UAC) by masquerading as a Microsoft trusted Windows directory. Attackers may bypass UAC to stealthily execute code with elevated permissions.

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109

UAC Bypass via Windows Firewall Snap-In Hijack

Identifies attempts to bypass User Account Control (UAC) by hijacking the Microsoft Management Console (MMC) Windows Firewall snap-in. Attackers bypass UAC to stealthily execute code with elevated permissions.

update

109

Unusual Parent-Child Relationship

Identifies Windows programs run from unexpected parent processes. This could indicate masquerading or other strange activity on a system.

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108

Unusual Print Spooler Child Process

Detects unusual Print Spooler service (spoolsv.exe) child processes. This may indicate an attempt to exploit privilege escalation vulnerabilities related to the Printing Service on Windows.

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105

Unusual Service Host Child Process - Childless Service

Identifies unusual child processes of Service Host (svchost.exe) that traditionally do not spawn any child processes. This may indicate a code injection or an equivalent form of exploitation.

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107

Privilege Escalation via Rogue Named Pipe Impersonation

Identifies a privilege escalation attempt via rogue named pipe impersonation. An adversary may abuse this technique by masquerading as a known named pipe and manipulating a privileged process to connect to it.

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105

Windows Service Installed via an Unusual Client

Identifies the creation of a Windows service by an unusual client process. Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges from administrator to SYSTEM.

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106