detection.wiki

Detection rules › Panther

GitHub Repository Collaborator Change

Severity
medium
Log types
GitHub.Audit
Tags
GitHub, Initial Access:Supply Chain Compromise
Reference
https://docs.github.com/en/organizations/managing-user-access-to-your-organizations-repositories/managing-repository-roles/managing-an-individuals-access-to-an-organization-repository
Source
github.com/panther-labs/panther-analysis

Detects when a repository collaborator is added or removed.

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1195 Supply Chain Compromise

Rule body yaml

AnalysisType: rule
Filename: github_repo_collaborator_change.py
RuleID: "Github.Repo.CollaboratorChange"
DisplayName: "GitHub Repository Collaborator Change"
Enabled: true
LogTypes:
  - GitHub.Audit
Tags:
  - GitHub
  - Initial Access:Supply Chain Compromise
Reports:
  MITRE ATT&CK:
    - TA0001:T1195
Severity: Medium
Description: Detects when a repository collaborator is added or removed.
Runbook: Determine if the new collaborator is authorized to access the repository.
Reference: https://docs.github.com/en/organizations/managing-user-access-to-your-organizations-repositories/managing-repository-roles/managing-an-individuals-access-to-an-organization-repository
Tests:
  - Name: GitHub - Collaborator Added
    ExpectedResult: true
    Log:
      {
        "actor": "bob",
        "action": "repo.add_member",
        "created_at": 1621305118553,
        "org": "my-org",
        "p_log_type": "GitHub.Audit",
        "repo": "my-org/my-repo",
        "user": "cat",
      }
  - Name: GitHub - Collaborator Removed
    ExpectedResult: true
    Log:
      {
        "actor": "bob",
        "action": "repo.remove_member",
        "created_at": 1621305118553,
        "org": "my-org",
        "p_log_type": "GitHub.Audit",
        "repo": "my-org/my-repo",
        "user": "cat",
      }
  - Name: GitHub - Non member action
    ExpectedResult: false
    Log:
      {
        "actor": "bob",
        "action": "repo.enable",
        "created_at": 1621305118553,
        "org": "my-org",
        "p_log_type": "GitHub.Audit",
        "repo": "my-org/my-repo",
        "user": "cat",
      }

Detection logic

Condition

action in ["repo.add_member", "repo.remove_member"]

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
actionin
  • repo.add_member
  • repo.remove_member

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field
user
repo