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Executable File Creation with Multiple Extensions
editExecutable File Creation with Multiple Extensions
editMasquerading 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: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References: None
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Defense Evasion
Version: 4
Rule authors:
- Elastic
Rule license: Elastic License v2
Investigation guide
edit## 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 query
editfile where event.type == "creation" and file.extension : "exe" and file.name regex~ """.*\.(vbs|vbe|bat|js|cmd|wsh|ps1|pdf|docx?|xlsx?|pptx?|txt|rtf|gif|jpg|png|bmp|hta|txt|img|iso)\.exe"""
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/
-
Sub-technique:
- Name: Masquerade Task or Service
- ID: T1036.004
- Reference URL: https://attack.mitre.org/techniques/T1036/004/
-
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/
-
Sub-technique:
- Name: Malicious File
- ID: T1204.002
- Reference URL: https://attack.mitre.org/techniques/T1204/002/