GitHub Organizations Delete Branch Ruleset

Name:GitHub Organizations Delete Branch Ruleset
id:8e454f64-4bd6-45e6-8a94-1b482593d721
version:1
date:2025-01-17
author:Patrick Bareiss, Splunk
status:production
type:Anomaly
Description:The following analytic detects when branch rulesets are deleted in GitHub Organizations. The detection monitors GitHub Organizations audit logs for branch ruleset deletion events by tracking actor details, repository information, and associated metadata. For a SOC, identifying deleted branch rulesets is critical as it could indicate attempts to bypass code review requirements and security controls. Branch rulesets 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 Organizations Audit Logs

search:`github_organizations` vendor_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, vendor_action, ruleset_name
| eval user=actor
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `github_organizations_delete_branch_ruleset_filter`

how_to_implement:You must ingest GitHub Organizations logs using Splunk Add-on for Github using a Personal Access Token https://docs.splunk.com/Documentation/AddOns/released/GitHub/Configureinputs .
known_false_positives:unknown
References:
  -https://docs.splunk.com/Documentation/AddOns/released/GitHub/Configureinputs
  -https://www.googlecloudcommunity.com/gc/Community-Blog/Monitoring-for-Suspicious-GitHub-Activity-with-Google-Security/ba-p/763610
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: github
  sourcetype: github:cloud:audit
manual_test:None