Update v8.15.3

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This section lists all updates associated with version 8.15.3 of the Fleet integration Prebuilt Security Detection Rules.

Rule Description Status Version

Dynamic Linker Creation or Modification

Detects the creation or modification of files related to the dynamic linker on Linux systems. The dynamic linker is a shared library that is used by the Linux kernel to load and execute programs. Attackers may attempt to hijack the execution flow of a program by modifying the dynamic linker configuration files.

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Suspicious File Downloaded from Google Drive

Identifies suspicious file download activity from a Google Drive URL. This could indicate an attempt to deliver phishing payloads via a trusted webservice.

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Active Directory Forced Authentication from Linux Host - SMB Named Pipes

Identifies a potential forced authentication using related SMB named pipes. Attackers may attempt to force targets to authenticate to a host controlled by them to capture hashes or enable relay attacks.

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AWS IAM SAML Provider Updated

Identifies when a user has updated a SAML provider in AWS. SAML providers are used to enable federated access to the AWS Management Console. This activity could be an indication of an attacker attempting to escalate privileges.

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AWS STS Temporary Credentials via AssumeRole

Identifies when a user has assumed a role in AWS Security Token Service (STS). Users can assume a role to obtain temporary credentials and access AWS resources. Adversaries can use this technique for credential access and privilege escalation.

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208

Machine Learning Detected a Suspicious Windows Event Predicted to be Malicious Activity

A supervised machine learning model (ProblemChild) has identified a suspicious Windows process event with high probability of it being malicious activity. Alternatively, the model’s blocklist identified the event as being malicious.

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Machine Learning Detected a Suspicious Windows Event with a High Malicious Probability Score

A supervised machine learning model (ProblemChild) has identified a suspicious Windows process event with high probability of it being malicious activity. Alternatively, the model’s blocklist identified the event as being malicious.

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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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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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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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Potential Network Sweep Detected

This rule identifies a potential network sweep. A network sweep is a method used by attackers to scan a target network, identifying active hosts, open ports, and available services to gather information on vulnerabilities and weaknesses. This reconnaissance helps them plan subsequent attacks and exploit potential entry points for unauthorized access, data theft, or other malicious activities. This rule proposes threshold logic to check for connection attempts from one source host to 10 or more destination hosts on commonly used network services.

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Potential Network Scan Detected

This rule identifies a potential port scan. A port scan is a method utilized by attackers to systematically scan a target system or network for open ports, allowing them to identify available services and potential vulnerabilities. By mapping out the open ports, attackers can gather critical information to plan and execute targeted attacks, gaining unauthorized access, compromising security, and potentially leading to data breaches, unauthorized control, or further exploitation of the targeted system or network. This rule proposes threshold logic to check for connection attempts from one source host to 20 or more destination ports.

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Potential SYN-Based Network Scan Detected

This rule identifies a potential SYN-Based port scan. A SYN port scan is a technique employed by attackers to scan a target network for open ports by sending SYN packets to multiple ports and observing the response. Attackers use this method to identify potential entry points or services that may be vulnerable to exploitation, allowing them to launch targeted attacks or gain unauthorized access to the system or network, compromising its security and potentially leading to data breaches or further malicious activities. This rule proposes threshold logic to check for connection attempts from one source host to 10 or more destination ports using 2 or less packets per port.

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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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Potential File Transfer via Certreq

Identifies Certreq making an HTTP Post request. Adversaries could abuse Certreq to download files or upload data to a remote URL.

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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.

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111

Potential File Download via a Headless Browser

Identifies the use of a browser to download a file from a remote URL and from a suspicious parent process. Adversaries may use browsers to avoid ingress tool transfer restrictions.

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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.

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First Time Seen Commonly Abused Remote Access Tool Execution

Adversaries may install legitimate remote access tools (RAT) to compromised endpoints for further command-and-control (C2). Adversaries can rely on installed RATs for persistence, execution of native commands and more. This rule detects when a process is started whose name or code signature resembles commonly abused RATs. This is a New Terms rule type indicating the host has not seen this RAT process started before within the last 30 days.

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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.

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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.

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113

Remote File Download via MpCmdRun

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

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113

Suspicious ScreenConnect Client Child Process

Identifies suspicious processes being spawned by the ScreenConnect client processes. This activity may indicate execution abusing unauthorized access to the ScreenConnect remote access software.

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205

Remote File Copy via TeamViewer

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

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112

Potential ADIDNS Poisoning via Wildcard Record Creation

Active Directory Integrated DNS (ADIDNS) is one of the core components of AD DS, leveraging AD’s access control and replication to maintain domain consistency. It stores DNS zones as AD objects, a feature that, while robust, introduces some security issues, such as wildcard records, mainly because of the default permission (Any authenticated users) to create DNS-named records. Attackers can create wildcard records to redirect traffic that doesn’t explicitly match records contained in the zone, becoming the Man-in-the-Middle and being able to abuse DNS similarly to LLMNR/NBNS spoofing.

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Potential WPAD Spoofing via DNS Record Creation

Identifies the creation of a DNS record that is potentially meant to enable WPAD spoofing. Attackers can disable the Global Query Block List (GQBL) and create a "wpad" record to exploit hosts running WPAD with default settings for privilege escalation and lateral movement.

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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.

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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.

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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.

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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.

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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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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.

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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.

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Potential Active Directory Replication Account Backdoor

Identifies the modification of the nTSecurityDescriptor attribute in a domain object with rights related to DCSync to a user/computer account. Attackers can use this backdoor to re-obtain access to hashes of any user/computer.

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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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Creation of a DNS-Named Record

Active Directory Integrated DNS (ADIDNS) is one of the core components of AD DS, leveraging AD’s access control and replication to maintain domain consistency. It stores DNS zones as AD objects, a feature that, while robust, introduces some security issues because of the default permission (Any authenticated users) to create DNS-named records. Attackers can perform Dynamic Spoofing attacks, where they monitor LLMNR/NBT-NS requests and create DNS-named records to target systems that are requested from multiple systems. They can also create specific records to target specific services, such as wpad, for spoofing attacks.

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Potential Relay Attack against a Domain Controller

Identifies potential relay attacks against a domain controller (DC) by identifying authentication events using the domain controller computer account coming from other hosts to the DC that owns the account. Attackers may relay the DC hash after capturing it using forced authentication.

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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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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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Kirbi File Creation

Identifies the creation of .kirbi files. The creation of this kind of file is an indicator of an attacker running Kerberos ticket dump utilities, such as Mimikatz, and precedes attacks such as Pass-The-Ticket (PTT), which allows the attacker to impersonate users using Kerberos tickets.

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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.

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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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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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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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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.

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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.

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Potential Local NTLM Relay via HTTP

Identifies attempt to coerce a local NTLM authentication via HTTP using the Windows Printer Spooler service as a target. An adversary may use this primitive in combination with other techniques to elevate privileges on a compromised system.

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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.

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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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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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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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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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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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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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Potential Veeam Credential Access Command

Identifies commands that can access and decrypt Veeam credentials stored in MSSQL databases. Attackers can use Veeam Credentials to target backups as part of destructive operations such as Ransomware attacks.

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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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NTDS Dump via Wbadmin

Identifies the execution of wbadmin to access the NTDS.dit file in a domain controller. Attackers with privileges from groups like Backup Operators can abuse the utility to perform credential access and compromise the domain.

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Wireless Credential Dumping using Netsh Command

Identifies attempts to dump Wireless saved access keys in clear text using the Windows built-in utility Netsh.

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Adding Hidden File Attribute via Attrib

Adversaries can add the hidden attribute to files to hide them from the user in an attempt to evade detection.

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Suspicious Antimalware Scan Interface DLL

Identifies the creation of the Antimalware Scan Interface (AMSI) DLL in an unusual location. This may indicate an attempt to bypass AMSI by loading a rogue AMSI module instead of the legit one.

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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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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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Windows Event Logs Cleared

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

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Code Signing Policy Modification Through Built-in tools

Identifies attempts to disable/modify the code signing policy through system native utilities. Code signing provides authenticity on a program, and grants the user with the ability to check whether the program has been tampered with. By allowing the execution of unsigned or self-signed code, threat actors can craft and execute malicious code.

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Windows CryptoAPI Spoofing Vulnerability (CVE-2020-0601 - CurveBall)

A spoofing vulnerability exists in the way Windows CryptoAPI (Crypt32.dll) validates Elliptic Curve Cryptography (ECC) certificates. An attacker could exploit the vulnerability by using a spoofed code-signing certificate to sign a malicious executable, making it appear the file was from a trusted, legitimate source.

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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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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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Delete Volume USN Journal with Fsutil

Identifies use of the fsutil.exe to delete the volume USNJRNL. This technique is used by attackers to eliminate evidence of files created during post-exploitation activities.

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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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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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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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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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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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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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110

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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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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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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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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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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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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Encoded Executable Stored in the Registry

Identifies registry write modifications to hide an encoded portable executable. This could be indicative of adversary defense evasion by avoiding the storing of malicious content directly on disk.

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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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Process Injection by the Microsoft Build Engine

An instance of MSBuild, the Microsoft Build Engine, created a thread in another process. This technique is sometimes used to evade detection or elevate privileges.

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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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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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MsBuild Making Network Connections

Identifies MsBuild.exe making outbound network connections. This may indicate adversarial activity as MsBuild is often leveraged by adversaries to execute code and evade detection.

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DNS Global Query Block List Modified or Disabled

Identifies changes to the DNS Global Query Block List (GQBL), a security feature that prevents the resolution of certain DNS names often exploited in attacks like WPAD spoofing. Attackers with certain privileges, such as DNSAdmins, can modify or disable the GQBL, allowing exploitation of hosts running WPAD with default settings for privilege escalation and lateral movement.

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SIP Provider Modification

Identifies modifications to the registered Subject Interface Package (SIP) providers. SIP providers are used by the Windows cryptographic system to validate file signatures on the system. This may be an attempt to bypass signature validation checks or inject code into critical processes.

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Suspicious CertUtil Commands

Identifies suspicious commands being used with certutil.exe. CertUtil is a native Windows component which is part of Certificate Services. CertUtil is often abused by attackers to live off the land for stealthier command and control or data exfiltration.

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Suspicious Script Object Execution

Identifies scrobj.dll loaded into unusual Microsoft processes. This usually means a malicious scriptlet is being executed in the target process.

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Suspicious Zoom Child Process

A suspicious Zoom child process was detected, which may indicate an attempt to run unnoticed. Verify process details such as command line, network connections, file writes and associated file signature details as well.

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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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Potential Evasion via Filter Manager

The Filter Manager Control Program (fltMC.exe) binary may be abused by adversaries to unload a filter driver and evade defenses.

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Potential Evasion via Windows Filtering Platform

Identifies multiple Windows Filtering Platform block events and where the process name is related to an endpoint security software. Adversaries may add malicious WFP rules to prevent Endpoint security from sending telemetry.

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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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Suspicious Execution via Windows Subsystem for Linux

Detects Linux Bash commands from the the Windows Subsystem for Linux. Adversaries may enable and use WSL for Linux to avoid detection.

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Execution via Windows Subsystem for Linux

Detects attempts to execute a program on the host from the Windows Subsystem for Linux. Adversaries may enable and use WSL for Linux to avoid detection.

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Windows Subsystem for Linux Enabled via Dism Utility

Detects attempts to enable the Windows Subsystem for Linux using Microsoft Dism utility. Adversaries may enable and use WSL for Linux to avoid detection.

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Attempt to Install Kali Linux via WSL

Detects attempts to install or use Kali Linux via Windows Subsystem for Linux. Adversaries may enable and use WSL for Linux to avoid detection.

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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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113

Enumeration of Administrator Accounts

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

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113

Enumerating Domain Trusts via DSQUERY.EXE

Identifies the use of dsquery.exe for domain trust discovery purposes. Adversaries may use this command-line utility to enumerate trust relationships that may be used for Lateral Movement opportunities in Windows multi-domain forest environments.

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Enumerating Domain Trusts via NLTEST.EXE

Identifies the use of nltest.exe for domain trust discovery purposes. Adversaries may use this command-line utility to enumerate domain trusts and gain insight into trust relationships, as well as the state of Domain Controller (DC) replication in a Microsoft Windows NT Domain.

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112

Group Policy Discovery via Microsoft GPResult Utility

Detects the usage of gpresult.exe to query group policy objects. Attackers may query group policy objects during the reconnaissance phase after compromising a system to gain a better understanding of the active directory environment and possible methods to escalate privileges or move laterally.

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9

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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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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312

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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113

Command Execution via SolarWinds Process

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

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112

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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110

Svchost spawning Cmd

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

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213

Downloaded Shortcut Files

Identifies .lnk shortcut file downloaded from outside the local network. These shortcut files are commonly used in phishing campaigns.

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3

Downloaded URL Files

Identifies .url shortcut files downloaded from outside the local network. These shortcut files are commonly used in phishing campaigns.

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3

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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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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113

Execution of File Written or Modified by Microsoft Office

Identifies an executable created by a Microsoft Office application and subsequently executed. These processes are often launched via scripts inside documents or during exploitation of Microsoft Office applications.

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111

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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112

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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111

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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111

Microsoft Management Console File from Unusual Path

Identifies attempts to open a Microsoft Management Console File from untrusted paths. Adversaries may use MSC files for initial access and execution.

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205

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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113

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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110

High Number of Process and/or Service Terminations

This rule identifies a high number (10) of process terminations (stop, delete, or suspend) from the same host within a short time period.

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110

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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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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112

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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111

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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Suspicious Execution from INET Cache

Identifies the execution of a process with arguments pointing to the INetCache Folder. Adversaries may deliver malicious content via WININET during initial access.

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3

Suspicious JetBrains TeamCity Child Process

Identifies suspicious processes being spawned by the JetBrain TeamCity process. This activity could be related to JetBrains remote code execution vulnerabilities.

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3

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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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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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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315

ScreenConnect Server Spawning Suspicious Processes

Identifies suspicious processes being spawned by the ScreenConnect server process (ScreenConnect.Service.exe). This activity may indicate exploitation activity or access to an existing web shell backdoor.

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2

Potential Pass-the-Hash (PtH) Attempt

Adversaries may pass the hash using stolen password hashes to move laterally within an environment, bypassing normal system access controls. Pass the hash (PtH) is a method of authenticating as a user without having access to the user’s cleartext password.

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4

NullSessionPipe Registry Modification

Identifies NullSessionPipe registry modifications that specify which pipes can be accessed anonymously. This could be indicative of adversary lateral movement preparation by making the added pipe available to everyone.

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110

SMB Connections via LOLBin or Untrusted Process

Identifies potentially suspicious processes that are not trusted or living-off-the-land binaries (LOLBin) making Server Message Block (SMB) network connections over port 445. Windows File Sharing is typically implemented over SMB, which communicates between hosts using port 445. Legitimate connections are generally established by the kernel (PID 4). This rule helps to detect processes that might be port scanners, exploits, or user-level processes attempting lateral movement within the network by leveraging SMB connections.

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111

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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110

Remote Execution via File Shares

Identifies the execution of a file that was created by the virtual system process. This may indicate lateral movement via network file shares.

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112

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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110

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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110

Remote Windows Service Installed

Identifies a network logon followed by Windows service creation with same LogonId. This could be indicative of lateral movement, but will be noisy if commonly done by administrators."

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7

Remote Scheduled Task Creation via RPC

Identifies scheduled task creation from a remote source. This could be indicative of adversary lateral movement.

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9

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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111

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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111

Potential WSUS Abuse for Lateral Movement

Identifies a potential Windows Server Update Services (WSUS) abuse to execute psexec to enable for lateral movement. WSUS is limited to executing Microsoft signed binaries, which limits the executables that can be used to tools published by Microsoft.

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104

AdminSDHolder Backdoor

Detects modifications in the AdminSDHolder object. Attackers can abuse the SDProp process to implement a persistent backdoor in Active Directory. 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, regaining their Administrative Privileges.

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108

Account Configured with Never-Expiring Password

Detects the creation and modification of an account with the "Don’t Expire Password" option Enabled. Attackers can abuse this misconfiguration to persist in the domain and maintain long-term access using compromised accounts with this property.

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109

Image File Execution Options Injection

The Debugger and SilentProcessExit registry keys can allow an adversary to intercept the execution of files, causing a different process to be executed. This functionality can be abused by an adversary to establish persistence.

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109

Suspicious Startup Shell Folder Modification

Identifies suspicious startup shell folder modifications to change the default Startup directory in order to bypass detections monitoring file creation in the Windows Startup folder.

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112

Active Directory Group Modification by SYSTEM

Identifies a user being added to an active directory group by the SYSTEM (S-1-5-18) user. This behavior can indicate that the attacker has achieved SYSTEM privileges in a domain controller, which attackers can obtain by exploiting vulnerabilities or abusing default group privileges (e.g., Server Operators), and is attempting to pivot to a domain account.

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2

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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108

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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110

Uncommon Registry Persistence Change

Detects changes to registry persistence keys that are not commonly used or modified by legitimate programs. This could be an indication of an adversary’s attempt to persist in a stealthy manner.

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110

Account Password Reset Remotely

Identifies an attempt to reset a potentially privileged account password remotely. Adversaries may manipulate account passwords to maintain access or evade password duration policies and preserve compromised credentials.

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116

A scheduled task was created

Indicates the creation of a scheduled task using Windows event logs. Adversaries can use these to establish persistence, move laterally, and/or escalate privileges.

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9

A scheduled task was updated

Indicates the update of a scheduled task using Windows event logs. Adversaries can use these to establish persistence, by changing the configuration of a legit scheduled task. Some changes such as disabling or enabling a scheduled task are common and may may generate noise.

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9

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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112

Suspicious Service was Installed in the System

Identifies the creation of a new Windows service with suspicious Service command values. Windows services typically run as SYSTEM and can be used for privilege escalation and persistence.

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10

Unusual Persistence via Services Registry

Identifies processes modifying the services registry key directly, instead of through the expected Windows APIs. This could be an indication of an adversary attempting to stealthily persist through abnormal service creation or modification of an existing service.

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110

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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112

Suspicious ImagePath Service Creation

Identifies the creation of a suspicious ImagePath value. This could be an indication of an adversary attempting to stealthily persist or escalate privileges through abnormal service creation.

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109

System Shells via Services

Windows services typically run as SYSTEM and can be used as a privilege escalation opportunity. Malware or penetration testers may run a shell as a service to gain SYSTEM permissions.

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314

Temporarily Scheduled Task Creation

Indicates the creation and deletion of a scheduled task within a short time interval. Adversaries can use these to proxy malicious execution via the schedule service and perform clean up.

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8

Potential Persistence via Time Provider Modification

Identifies modification of the Time Provider. Adversaries may establish persistence by registering and enabling a malicious DLL as a time provider. Windows uses the time provider architecture to obtain accurate time stamps from other network devices or clients in the network. Time providers are implemented in the form of a DLL file which resides in the System32 folder. The service W32Time initiates during the startup of Windows and loads w32time.dll.

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111

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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111

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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110

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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111

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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111

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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112

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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112

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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314

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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10

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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11

Unsigned DLL loaded by DNS Service

Identifies unusual DLLs loaded by the DNS Server process, potentially indicating the abuse of the ServerLevelPluginDll functionality. This can lead to privilege escalation and remote code execution with SYSTEM privileges.

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2

Potential privilege escalation via CVE-2022-38028

Identifies a privilege escalation attempt via exploiting CVE-2022-38028 to hijack the print spooler service execution.

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2

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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111

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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111

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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112

Service Creation via Local Kerberos Authentication

Identifies a suspicious local successful logon event where the Logon Package is Kerberos, the remote address is set to localhost, followed by a sevice creation from the same LogonId. This may indicate an attempt to leverage a Kerberos relay attack variant that can be used to elevate privilege locally from a domain joined user to local System privileges.

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106

Interactive Logon by an Unusual Process

Identifies interactive logon attempt with alternate credentials and by an unusual process. Adversaries may create a new token to escalate privileges and bypass access controls.

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4

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.

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111

First Time Seen NewCredentials Logon Process

Identifies a new credentials logon type performed by an unusual process. This may indicate the existence of an access token forging capability that are often abused to bypass access control restrictions.

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3

Suspicious Print Spooler Point and Print DLL

Detects attempts to exploit a privilege escalation vulnerability (CVE-2020-1030) related to the print spooler service. Exploitation involves chaining multiple primitives to load an arbitrary DLL into the print spooler process running as SYSTEM.

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107

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.

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109

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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112

Potential Privilege Escalation via Service ImagePath Modification

Identifies registry modifications to default services that could enable privilege escalation to SYSTEM. Attackers with privileges from groups like Server Operators may change the ImagePath of services to executables under their control or to execute commands.

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2

Privilege Escalation via Windir Environment Variable

Identifies a privilege escalation attempt via a rogue Windows directory (Windir) environment variable. This is a known primitive that is often combined with other vulnerabilities to elevate privileges.

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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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109

Service Control Spawned via Script Interpreter

Identifies Service Control (sc.exe) spawning from script interpreter processes to create, modify, or start services. This can potentially indicate an attempt to elevate privileges or maintain persistence.

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110

Remote Computer Account DnsHostName Update

Identifies the remote update to a computer account’s DnsHostName attribute. If the new value set is a valid domain controller DNS hostname and the subject computer name is not a domain controller, then it’s highly likely a preparation step to exploit CVE-2022-26923 in an attempt to elevate privileges from a standard domain user to domain admin privileges.

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108

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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8

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.

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110

Bypass UAC via Event Viewer

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

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114

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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114

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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112

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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109

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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110