Image Loaded with Invalid Signature

Identifies binaries that are loaded and with an invalid code signature. This may indicate an attempt to masquerade as a signed binary.

Rule type: eql

Rule indices:

logs-endpoint.events.library-*

Severity: low

Risk score: 21

Runs every: 60m

Searches indices from: now-119m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

Domain: Endpoint
OS: Windows
Use Case: Threat Detection
Tactic: Defense Evasion
Rule Type: BBR
Data Source: Elastic Defend

Version: 2

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

library where host.os.type == "windows" and event.action == "load" and
  dll.code_signature.status : ("errorUntrustedRoot", "errorBadDigest", "errorUntrustedRoot") and
  (dll.Ext.relative_file_creation_time <= 500 or dll.Ext.relative_file_name_modify_time <= 500) and
  not startswith~(dll.name, process.name) and
  not dll.path : (
    "?:\\Windows\\System32\\DriverStore\\FileRepository\\*"
  )

Framework: MITRE ATT&CK^TM

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: Invalid Code Signature
- ID: T1036.001
- Reference URL: https://attack.mitre.org/techniques/T1036/001/

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