Detection: GitHub Enterprise Disable IP Allow List

Updated Date: 2025-01-20 ID: afed020e-edcd-4913-a675-cebedf81d4fb Author: Patrick Bareiss, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic identifies when an IP allow list is disabled in GitHub Enterprise. The detection monitors GitHub Enterprise audit logs for actions related to disabling IP allow lists at the organization or enterprise level. This behavior is concerning because IP allow lists are a critical security control that restricts access to GitHub Enterprise resources to only trusted IP addresses. When disabled, it could indicate an attacker attempting to bypass access controls to gain unauthorized access from untrusted networks. The impact includes potential exposure of sensitive code repositories and GitHub Enterprise resources to access from any IP address. SOC teams should investigate such events, especially if they were not pre-approved changes, as they may indicate compromise of admin credentials or malicious insider activity.

1`github_enterprise` action=ip_allow_list.disable 
2| fillnull 
3| stats count min(_time) as firstTime max(_time) as lastTime by actor, actor_id, actor_is_bot, actor_location.country_code, business, business_id, user_agent, user_id, action 
4| eval user=actor 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `github_enterprise_disable_ip_allow_list_filter`

Data Source

Name Platform Sourcetype Source
GitHub Enterprise Audit Logs N/A 'httpevent' 'http:github'

Macros Used

Name Value
github_enterprise source=http:github sourcetype=httpevent
github_enterprise_disable_ip_allow_list_filter search *
github_enterprise_disable_ip_allow_list_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1562.001 Disable or Modify Tools Defense Evasion
T1195 Supply Chain Compromise Initial Access
Delivery
Exploitation
DE.AE
CIS 13

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

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

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

$user$ disabled an IP allow list in GitHub Enterprise

Risk Object Risk Object Type Risk Score Threat Objects
user user 25 user_agent

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset http:github httpevent
Integration ✅ Passing Dataset http:github httpevent

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1