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.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.*
logs-windows.*

Severity: high

Risk score: 73

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion

Version: 4 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 7.13.0

Rule authors: Elastic

Rule license: Elastic License v2

Rule query

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file where event.type != "deletion" and file.extension : ("exe",
"dll") and process.name : ("smss.exe",
"autochk.exe", "csrss.exe",
"wininit.exe", "services.exe",
"lsass.exe", "winlogon.exe",
"userinit.exe", "LogonUI.exe")

Threat mapping

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Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Exploitation for Defense Evasion
- ID: T1211
- Reference URL: https://attack.mitre.org/techniques/T1211/

Rule version history

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Version 4 (7.13.0 release)

Updated query, changed from:

event.category:file and not event.type:deletion and
file.extension:(exe or dll) and process.name:(smss.exe or autochk.exe
or csrss.exe or wininit.exe or services.exe or lsass.exe or
winlogon.exe or userinit.exe or LogonUI.exe)

Version 3 (7.12.0 release)

Formatting only

Version 2 (7.11.2 release)

Formatting only

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