Windows Suspicious Script Object Execution

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Identifies scrobj.dll loaded into unusual Microsoft processes. This usually means a malicious scriptlet is being executed in the target process.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*
  • winlogbeat-*

Severity: medium

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
  • Windows
  • Threat Detection
  • Defense Evasion

Version: 1

Added (Elastic Stack release): 7.10.0

Rule authors: Elastic

Rule license: Elastic License

Rule query

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/* add winlogbeat-* when process.code_signature.* fields are populated
*/ sequence by process.entity_id with maxspan=2m [process where
event.type in ("start", "process_started") and /* uncomment once
in winlogbeat */ /* process.code_signature.subject_name ==
"Microsoft Corporation" and process.code_signature.trusted == true and
*/ not (process.name : "cscript.exe" or process.name :
"iexplore.exe" or process.name : "MicrosoftEdge.exe" or
process.name : "msiexec.exe" or process.name :
"smartscreen.exe" or process.name : "taskhostw.exe" or
process.name : "w3wp.exe" or process.name : "wscript.exe")]
[library where event.type == "start" and file.name : "scrobj.dll"]

Threat mapping

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Framework: MITRE ATT&CKTM