Sigma rule: Github Outside Collaborator Detected

Rule

Title

Github Outside Collaborator Detected

Status

test

Level

medium

Author

Muhammad Faisal (@faisalusuf)

Date

2023-01-20

File

rules/application/github/audit/github_outside_collaborator_detected.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects when an organization member or an outside collaborator is added to or removed from a project board or has their permission level changed or when an owner removes an outside collaborator from an organization or when two-factor authentication is required in an organization and an outside collaborator does not use 2FA or disables 2FA.

Log source

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:
        - 'org.remove_outside_collaborator'
        - 'project.update_user_permission'
condition: selection

False positives (as the rule lists them)

• Validate the actor if permitted to access the repo.
• Validate the Multifactor Authentication changes.

Tags

• attack.privilege-escalation
• attack.persistence
• attack.collection
• attack.t1098.001
• attack.t1098.003
• attack.t1213.003

MITRE ATT&CK ids this rule names

• T1098.001
• T1098.003
• T1213.003

References

• https://docs.github.com/en/organizations/keeping-your-organization-secure/managing-security-settings-for-your-organization/reviewing-the-audit-log-for-your-organization#audit-log-actions
• https://docs.github.com/en/organizations/keeping-your-organization-secure/managing-two-factor-authentication-for-your-organization/requiring-two-factor-authentication-in-your-organization

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/application/github/audit/github_outside_collaborator_detected.yml