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 CertUtil
editEncoding or Decoding Files via CertUtil
editIdentifies 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 query
editevent.action:"Process Create (rule: ProcessCreate)" and process.name:certutil.exe and process.args:(-decode or -encode or /decode or /encode)
Threat mapping
editFramework: 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 history
edit- 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")