Certificate Private Key Acquired — Sigma Rule

Rule metadata and linked tags

Author: Zach Mathis. Source status: test; severity: medium. Source dates: 2023-05-13 / not supplied.

{
  "product": "windows",
  "service": "capi2",
  "definition": "Requirements: The CAPI2 Operational log needs to be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 354be3ee2cb17757993b1fa9d45cd61dfc5c03f0e099767a8b7a3e7c78b2d6b4

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: Certificate Private Key Acquired
id: e2b5163d-7deb-4566-9af3-40afea6858c3
status: test
description: Detects when an application acquires a certificate private key
references:
    - https://www.splunk.com/en_us/blog/security/breaking-the-chain-defending-against-certificate-services-abuse.html
author: Zach Mathis
date: 2023-05-13
tags:
    - attack.credential-access
    - attack.t1649
logsource:
    product: windows
    service: capi2
    definition: 'Requirements: The CAPI2 Operational log needs to be enabled'
detection:
    selection:
        EventID: 70 # Acquire Certificate Private Key
    condition: selection
falsepositives:
    - Legitimate application requesting certificate exports will trigger this. Apply additional filters as needed
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate application requesting certificate exports will trigger this. Apply additional filters as needed

Source references

• https://www.splunk.com/en_us/blog/security/breaking-the-chain-defending-against-certificate-services-abuse.html