Base16 or Base32 Encoding/Decoding Activityedit
Adversaries may encode/decode data in an attempt to evade detection by host- or network-based security controls.
Rule type: query
Rule indices:
- auditbeat-*
- logs-endpoint.events.*
Severity: low
Risk score: 21
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
- Linux
- Threat Detection
- Defense Evasion
Version: 100 (version history)
Added (Elastic Stack release): 7.8.0
Last modified (Elastic Stack release): 8.5.0
Rule authors: Elastic
Rule license: Elastic License v2
Potential false positivesedit
Automated tools such as Jenkins may encode or decode files as part of their normal behavior. These events can be filtered by the process executable or username values.
Rule queryedit
event.category:process and event.type:(start or process_started) and process.name:(base16 or base32 or base32plain or base32hex)
Threat mappingedit
Framework: MITRE ATT&CKTM
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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 100 (8.5.0 release)
-
- Formatting only
- Version 8 (8.4.0 release)
-
- Formatting only
- Version 7 (7.12.0 release)
-
- Formatting only
- Version 6 (7.11.2 release)
-
- Formatting only
- Version 5 (7.11.0 release)
-
- Formatting only
- Version 4 (7.10.0 release)
-
- Formatting only
- Version 3 (7.9.1 release)
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- Formatting only
- Version 2 (7.9.0 release)
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-
Updated query, changed from:
event.action:(executed or process_started) and process.name:(base16 or base32 or base32plain or base32hex)
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