IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.

« Suspicious WMIC XSL Script Execution Suspicious Zoom Child Process »

› › ›

Suspicious WerFault Child Process

edit

Suspicious WerFault Child Process

edit

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

Rule type: eql

Rule indices:

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

Severity: medium

Risk score: 47

Runs every: 5 minutes

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

Maximum alerts per execution: 100

References:

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion

Version: 7 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 8.4.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

edit

Custom Windows error reporting debugger or applications restarted by WerFault after a crash.

Investigation guide

edit

Rule query

edit

process where event.type in ("start", "process_started") and
process.parent.name : "WerFault.exe" and not process.name :
("cofire.exe", "psr.exe",
"VsJITDebugger.exe", "TTTracer.exe",
"rundll32.exe", "LogiOptionsMgr.exe") and not
process.args : ("/LOADSAVEDWINDOWS", "/restore",
"RestartByRestartManager*", "--restarted",
"createdump", "dontsend",
"/watson")

Threat mapping

edit

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Masquerading
- ID: T1036
- Reference URL: https://attack.mitre.org/techniques/T1036/

Rule version history

edit

Version 7 (8.4.0 release)

Formatting only

Version 5 (8.2.0 release)

Formatting only

Version 4 (7.13.0 release)

Updated query, changed from:

event.category:process and event.type:(start or process_started) and
process.parent.name:WerFault.exe and not process.name:(cofire.exe or
psr.exe or VsJITDebugger.exe or TTTracer.exe or rundll32.exe)

Version 3 (7.12.0 release)

Formatting only

Version 2 (7.11.2 release)

Formatting only

« Suspicious WMIC XSL Script Execution Suspicious Zoom Child Process »