Suspicious X509Enrollment - Ps Script — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2022-12-23 / not supplied.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: bb36c878f21c65b5921c62f63d7caae047ad058fe956528cbf6dc5b571537d0e

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious X509Enrollment - Ps Script
id: 504d63cb-0dba-4d02-8531-e72981aace2c
related:
    - id: 114de787-4eb2-48cc-abdb-c0b449f93ea4
      type: similar
status: test
description: Detect use of X509Enrollment
references:
    - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=42
    - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=41
    - https://learn.microsoft.com/en-us/dotnet/api/microsoft.hpc.scheduler.store.cx509enrollmentwebclassfactoryclass?view=hpc-sdk-5.1.6115
author: frack113
date: 2022-12-23
tags:
    - attack.defense-impairment
    - attack.t1553.004
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains:
            - 'X509Enrollment.CBinaryConverter'
            - '884e2002-217d-11da-b2a4-000e7bbb2b09'
    condition: selection
falsepositives:
    - Legitimate administrative script
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate administrative script

Source references

• https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=42
• https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=41
• https://learn.microsoft.com/en-us/dotnet/api/microsoft.hpc.scheduler.store.cx509enrollmentwebclassfactoryclass?view=hpc-sdk-5.1.6115