GitHub Enterprise Delete Branch Ruleset

Name:GitHub Enterprise Delete Branch Ruleset
id:6169ea23-3719-439f-957a-0ea5174b70e2
version:1
date:2025-01-17
author:Patrick Bareiss, Splunk
status:production
type:Anomaly
Description:The following analytic detects when branch rules are deleted in GitHub Enterprise. The detection monitors GitHub Enterprise audit logs for branch rule deletion events by tracking actor details, repository information, and associated metadata. For a SOC, identifying deleted branch rules is critical as it could indicate attempts to bypass code review requirements and security controls. Branch deletion rules are essential security controls that enforce code review, prevent force pushes, and maintain code quality. Disabling these protections could allow malicious actors to directly push unauthorized code changes or backdoors to protected branches. The impact of disabled branch protection includes potential code tampering, bypass of security reviews, introduction of vulnerabilities or malicious code, and compromise of software supply chain integrity. This activity could be part of a larger attack chain where an adversary first disables security controls before attempting to inject malicious code.
Data_source:

• -GitHub Enterprise Audit Logs

search:`github_enterprise` action=repository_ruleset.destroy
| fillnull
| stats count min(_time) as firstTime max(_time) as lastTime by actor, actor_id, actor_ip, actor_is_bot, actor_location.country_code, business, business_id, org, org_id, repo, repo_id, user_agent, action, ruleset_name
| eval user=actor
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `github_enterprise_delete_branch_ruleset_filter`

how_to_implement:You must ingest GitHub Enterprise logs using Audit log streaming as described in this documentation 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-streaming-to-splunk using a Splunk HTTP Event Collector.
known_false_positives:unknown
References:
  -https://www.googlecloudcommunity.com/gc/Community-Blog/Monitoring-for-Suspicious-GitHub-Activity-with-Google-Security/ba-p/763610
  -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-streaming-to-splunk
drilldown_searches:
 name:'View the detection results for - "$user$"'
 search:'%original_detection_search% | search user = "$user$"'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
 name:'View risk events for the last 7 days for - "$user$"'
 search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
tags:
  analytic_story:
    - 'GitHub Malicious Activity'
  asset_type:GitHub
  mitre_attack_id:
    - 'T1562.001'
    - 'T1195'
  product:
    - 'Splunk Enterprise'
    - 'Splunk Enterprise Security'
    - 'Splunk Cloud'
  security_domain:network

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.001/github_delete_branch_ruleset/github.json
  source: http:github
  sourcetype: httpevent
manual_test:None