CVE-2024-11669: GitLab Auth Bypass Vulnerability

CVE-2024-11669 Overview

An authorization bypass vulnerability has been discovered in GitLab CE/EE affecting multiple versions starting from 16.9.8. The flaw exists in certain API endpoints that could potentially allow unauthorized access to sensitive data due to overly broad application of token scopes. This vulnerability enables attackers with valid API tokens to access data beyond their intended authorization scope, potentially exposing confidential repository information, user data, or project configurations.

Critical Impact

Unauthorized access to sensitive data via API token scope bypass could lead to significant data exposure in GitLab instances, particularly affecting organizations with strict access control requirements.

Affected Products

• GitLab Community Edition (CE) versions 16.9.8 before 17.4.5
• GitLab Enterprise Edition (EE) versions 17.5 before 17.5.3
• GitLab CE/EE version 17.6 before 17.6.1

Discovery Timeline

• 2024-11-26 - CVE CVE-2024-11669 published to NVD
• 2024-12-12 - Last updated in NVD database

Technical Details for CVE-2024-11669

Vulnerability Analysis

This vulnerability is classified as CWE-863 (Incorrect Authorization), indicating a fundamental flaw in how GitLab's API endpoints validate and enforce token scope restrictions. The issue stems from the improper implementation of authorization checks at certain API endpoints, where token scopes are applied too broadly, allowing tokens with limited intended permissions to access resources outside their designated scope.

The vulnerability can be exploited over the network without requiring user interaction. An attacker possessing a valid API token—even one with minimal permissions—could potentially leverage the overly permissive scope validation to read sensitive data that should be restricted. This represents a significant confidentiality risk, particularly in multi-tenant environments or organizations where different teams have varying levels of access to repositories and project data.

Root Cause

The root cause of this vulnerability lies in the overly broad application of token scopes within GitLab's API authorization layer. When API requests are processed, the authorization checks fail to properly restrict token permissions to their intended scope boundaries. This means that certain API endpoints do not adequately validate whether a given token has the specific permissions required to access the requested resource, instead relying on a broader scope check that permits unintended access.

Attack Vector

The attack vector for this vulnerability is network-based, requiring an attacker to have a valid API token for the target GitLab instance. The exploitation scenario involves:

1. An attacker obtains or creates a valid API token with limited scope permissions
2. The attacker crafts API requests to endpoints that should be restricted based on the token's intended scope
3. Due to the improper scope validation, the API endpoints process the request and return sensitive data
4. The attacker gains unauthorized access to confidential information such as repository contents, project configurations, or user data

The vulnerability is particularly concerning because it does not require any user interaction and can be exploited remotely. Organizations using GitLab for sensitive code repositories or with strict access segregation requirements are at elevated risk.

For technical details on the specific endpoints affected, refer to the GitLab Issue #501528.

Detection Methods for CVE-2024-11669

Indicators of Compromise

• Unusual API access patterns where tokens access resources outside their normal operational scope
• Increased API requests from tokens that typically have limited usage
• Access logs showing API endpoints being queried by tokens without appropriate scope assignments
• Anomalous data retrieval patterns from sensitive repositories or project configurations

Detection Strategies

• Monitor GitLab API access logs for tokens accessing resources outside their defined scope
• Implement alerting on API requests that return data inconsistent with token permission levels
• Review authentication logs for tokens exhibiting unusual access patterns or scope violations
• Deploy network monitoring to detect abnormal API traffic volumes to GitLab instances

Monitoring Recommendations

• Enable comprehensive API audit logging in GitLab to capture all token-based requests
• Configure SIEM alerts for patterns indicative of authorization bypass attempts
• Regularly review API token usage reports to identify anomalous access patterns
• Implement rate limiting and anomaly detection on sensitive API endpoints

How to Mitigate CVE-2024-11669

Immediate Actions Required

• Upgrade GitLab CE/EE to version 17.4.5, 17.5.3, or 17.6.1 immediately
• Audit all existing API tokens and revoke any with overly broad or unnecessary permissions
• Review API access logs for evidence of unauthorized data access
• Implement network segmentation to limit external access to GitLab API endpoints where possible

Patch Information

GitLab has released security patches addressing this vulnerability in the following versions:

• GitLab 17.4.5 - Patches versions from 16.9.8 to 17.4.x
• GitLab 17.5.3 - Patches versions 17.5.x
• GitLab 17.6.1 - Patches version 17.6.0

Organizations should upgrade to the appropriate patched version based on their current deployment. For detailed upgrade instructions, consult the GitLab Issue #501528 for additional context on the fix.

Workarounds

• Implement strict API token scope policies, limiting tokens to minimum required permissions
• Enable IP allowlisting for API access where possible to restrict token usage to known networks
• Consider temporarily disabling or restricting access to non-essential API endpoints until patching is complete
• Deploy Web Application Firewall (WAF) rules to monitor and potentially block suspicious API access patterns

# Configuration example - Review and audit GitLab API tokens
# List all personal access tokens via Rails console
gitlab-rails runner "PersonalAccessToken.all.each { |t| puts \"Token: #{t.name}, User: #{t.user.username}, Scopes: #{t.scopes}, Expires: #{t.expires_at}\" }"

# Revoke tokens with overly broad scopes (adjust as needed)
# gitlab-rails runner "PersonalAccessToken.where('scopes @> ARRAY[?]::varchar[]', 'api').update_all(revoked: true)"