A newer version is available. For the latest information, see the
current release documentation.
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")