Github Fork Private Repositories Setting Enabled/Cleared — Sigma Rule

Rule metadata and linked tags

Author: Romain Gaillard (@romain-gaillard). Source status: test; severity: medium. Source dates: 2024-07-29 / not supplied.

{
  "product": "github",
  "service": "audit",
  "definition": "Requirements: The audit log streaming feature must be enabled to be able to receive such logs. You can enable following the documentation here: https://docs.github.com/en/enterprise-cloud@latest/admin/monitoring-activity-in-your-enterprise/reviewing-audit-logs-for-your-enterprise/streaming-the-audit-log-for-your-enterprise#setting-up-audit-log-streaming"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 94dca97f362a33fc612cb98df8c81631dddc56fa185f0a02c9d6bbe445c3b9a4

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: Github Fork Private Repositories Setting Enabled/Cleared
id: 69b3bd1e-b38a-462f-9a23-fbdbf63d2294
status: test
description: |
    Detects when the policy allowing forks of private and internal repositories is changed (enabled or cleared).
references:
    - https://docs.github.com/en/enterprise-cloud@latest/admin/monitoring-activity-in-your-enterprise/reviewing-audit-logs-for-your-enterprise/audit-log-events-for-your-enterprise#private_repository_forking
author: Romain Gaillard (@romain-gaillard)
date: 2024-07-29
tags:
    - attack.persistence
    - attack.exfiltration
    - attack.t1020
    - attack.t1537
logsource:
    product: github
    service: audit
    definition: 'Requirements: The audit log streaming feature must be enabled to be able to receive such logs. You can enable following the documentation here: https://docs.github.com/en/enterprise-cloud@latest/admin/monitoring-activity-in-your-enterprise/reviewing-audit-logs-for-your-enterprise/streaming-the-audit-log-for-your-enterprise#setting-up-audit-log-streaming'
detection:
    selection:
        action:
            - 'private_repository_forking.clear' # An enterprise owner cleared the policy setting for allowing forks of private and internal repositories, for a repository, organization or enterprise.
            - 'private_repository_forking.enable' # An enterprise owner enabled the policy setting for allowing forks of private and internal repositories, for a repository, organization or enterprise. Private and internal repositories are always allowed to be forked.
    condition: selection
falsepositives:
    - Allowed administrative activities.
level: medium

Original YAML and metadata in JSON

False positives

• Allowed administrative activities.

Source references

• https://docs.github.com/en/enterprise-cloud@latest/admin/monitoring-activity-in-your-enterprise/reviewing-audit-logs-for-your-enterprise/audit-log-events-for-your-enterprise#private_repository_forking