Certificate Exported Via PowerShell — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2023-05-18 / not supplied.

{
  "product": "windows",
  "category": "process_creation"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 170bb757081ef3e6955521965ae2274b850bb24668388899d910991527c67632

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 Exported Via PowerShell
id: 9e716b33-63b2-46da-86a4-bd3c3b9b5dfb
related:
    - id: aa7a3fce-bef5-4311-9cc1-5f04bb8c308c
      type: similar
status: test
description: Detects calls to cmdlets that are used to export certificates from the local certificate store. Threat actors were seen abusing this to steal private keys from compromised machines.
references:
    - https://us-cert.cisa.gov/ncas/analysis-reports/ar21-112a
    - https://learn.microsoft.com/en-us/powershell/module/pki/export-pfxcertificate?view=windowsserver2022-ps
    - https://www.splunk.com/en_us/blog/security/breaking-the-chain-defending-against-certificate-services-abuse.html
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-18
tags:
    - attack.credential-access
    - attack.execution
    - attack.t1552.004
    - attack.t1059.001
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        CommandLine|contains:
            - 'Export-PfxCertificate '
            - 'Export-Certificate '
    condition: selection
falsepositives:
    - Legitimate certificate exports by administrators. Additional filters might be required.
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate certificate exports by administrators. Additional filters might be required.

Source references

• https://us-cert.cisa.gov/ncas/analysis-reports/ar21-112a
• https://learn.microsoft.com/en-us/powershell/module/pki/export-pfxcertificate?view=windowsserver2022-ps
• https://www.splunk.com/en_us/blog/security/breaking-the-chain-defending-against-certificate-services-abuse.html