The SIEM app is now a part of the Elastic Security solution.
Click
here to view the current documentation.
IMPORTANT: No additional bug fixes or documentation updates will be released for this version.
IMPORTANT: No additional bug fixes or documentation updates will be released for this version.
Encoding or Decoding Files via CertUtiledit
Identifies the use of certutil.exe
to encode or decode data. CertUtil is a
native Windows component which is part of Certificate Services. CertUtil is
often abused by attackers to encode or decode base64 data for stealthier command
and control or exfiltration.
Rule type: query
Rule indices:
- winlogbeat-*
Severity: medium
Risk score: 47
Runs every: 5 minutes
Searches indices from: now-6m (Date Math format, see also Additional look-back time
)
Maximum signals per execution: 100
Tags:
- Elastic
- Windows
Version: 2 (version history)
Added (Elastic Stack release): 7.6.0
Last modified (Elastic Stack release): 7.7.0
Rule queryedit
event.action:"Process Create (rule: ProcessCreate)" and process.name:certutil.exe and process.args:(-decode or -encode or /decode or /encode)
Threat mappingedit
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Deobfuscate/Decode Files or Information
- ID: T1140
- Reference URL: https://attack.mitre.org/techniques/T1140/
Rule version historyedit
- Version 2 (7.7.0 release)
-
Updated query, changed from:
event.action:"Process Create (rule: ProcessCreate)" and process.name:"certutil.exe" and process.args:("-encode" or "/encode" or "-decode" or "/decode")