GitHub Enterprise Modify Audit Log Event Stream

Name:GitHub Enterprise Modify Audit Log Event Stream
id:99abf2e1-863c-4ec6-82f8-714391590a4c
version:1
date:2025-01-16
author:Patrick Bareiss, Splunk
status:production
type:Anomaly
Description:The following analytic detects when a user modifies or disables audit log event streaming in GitHub Enterprise. The detection monitors GitHub Enterprise audit logs for configuration changes that affect the audit log streaming functionality, which is used to send audit events to security monitoring platforms. This behavior could indicate an attacker attempting to prevent their malicious activities from being logged and detected by tampering with the audit trail. For a SOC, identifying modifications to audit logging is critical as it may be a precursor to other attacks where adversaries want to operate undetected. The impact could be severe as organizations lose visibility into user actions, configuration changes, and security events within their GitHub Enterprise environment, potentially allowing attackers to perform malicious activities without detection. This creates a significant blind spot in security monitoring and incident response capabilities.
Data_source:

• -GitHub Enterprise Audit Logs

search:`github_enterprise` action=audit_log_streaming.update
| 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, user_agent, action
| eval user=actor
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `github_enterprise_modify_audit_log_event_stream_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:
    - 'T1562.008'
    - '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/T1562.008/github_audit_log_stream_modified/github.json
  source: http:github
  sourcetype: httpevent
manual_test:None