IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Executable File Creation with Multiple Extensionsedit
Masquerading can allow an adversary to evade defenses and better blend in with the environment. One way it occurs is when the name or location of a file is manipulated as a means of tricking a user into executing what they think is a benign file type but is actually executable code.
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
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Defense Evasion
Version: 4 (version history)
Added (Elastic Stack release): 7.12.0
Last modified (Elastic Stack release): 8.2.0
Rule authors: Elastic
Rule license: Elastic License v2
Investigation guideedit
## Config If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
Rule queryedit
file where event.type == "creation" and file.extension : "exe" and file.name regex~ """.*\.(vbs|vbe|bat|js|cmd|wsh|ps1|pdf|docx?|xlsx?|pp tx?|txt|rtf|gif|jpg|png|bmp|hta|txt|img|iso)\.exe"""
Threat mappingedit
Framework: MITRE ATT&CKTM
-
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/
-
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
-
Technique:
- Name: User Execution
- ID: T1204
- Reference URL: https://attack.mitre.org/techniques/T1204/
Rule version historyedit
- Version 4 (8.2.0 release)
-
- Formatting only
- Version 3 (7.16.0 release)
-
- Formatting only
- Version 2 (7.14.0 release)
-
-
Updated query, changed from:
file where event.type == "creation" and file.extension:"exe" and file.name: ( "*.vbs.exe", "*.vbe.exe", "*.bat.exe", "*.js.exe", "*.cmd.exe", "*.wsh.exe", "*.ps1.exe", "*.pdf.exe", "*.docx.exe", "*.doc.exe", "*.xlsx.exe", "*.xls.exe", "*.pptx.exe", "*.ppt.exe", "*.txt.exe", "*.rtf.exe", "*.gif.exe", "*.jpg.exe", "*.png.exe", "*.bmp.exe", "*.hta.exe", "*.txt.exe", "*.img.exe", "*.iso.exe" )
-