CVE-2022-4054 - GitLab Webhook Secret Token Leak Vulnerability

A security vulnerability, CVE-2022-4054, has been discovered in GitLab, which is a popular web-based Git repository manager. This vulnerability affects all versions starting from 9.3 before 15.4.6, all versions starting from 15.5 before 15.5.5, all versions starting from 15.6 before 15.6.1. The issue allows project maintainers to leak a webhook secret token by changing the webhook URL to an endpoint that captures request headers. This post will provide an overview of the vulnerability, details on how it can be exploited, and links to original references.

Vulnerability Details

GitLab uses webhook secret tokens to ensure the authenticity of webhook events. The tokens are typically sent with each webhook request so that the receiving server can validate the authenticity of the request before processing it. In CVE-2022-4054, a project maintainer could manipulate the webhook URL to point to a server within their control, subsequently capturing request headers and gaining access to the webhook secret token.

Here's a brief code snippet that illustrates a typical GitLab webhook request header

POST /webhook HTTP/1.1
Host: example.com
User-Agent: GitLab/14..
Content-Type: application/json
X-Gitlab-Event: Push Hook
X-Gitlab-Token: <SECRET_WEBHOOK_TOKEN>
Content-Length: 1245

An attacker could change the webhook URL in the GitLab project settings, redirecting webhook requests to their own malicious server, and obtaining the webhook secret token in the process. The attacker could then use the leaked token to craft malicious webhook events, potentially leading to unauthorized access, data breaches, or other damaging consequences.

Below is a high-level overview of the steps an attacker could take to exploit this vulnerability

1. The attacker, being a project maintainer, changes the webhook URL in the GitLab project settings to point to their own server.
2. The malicious server captures the request headers from incoming webhook requests, including the X-Gitlab-Token header containing the webhook secret token.
3. The attacker now has access to the secret token and can use it to create forged webhook events, potentially leading to harmful actions.

Mitigation and Recommendations

GitLab has released security updates to address this vulnerability. It is strongly recommended that users upgrade their GitLab installations to the latest patch version:

For GitLab versions starting from 15.6 before 15.6.1, upgrade to 15.6.1 or higher.

In addition, it is recommended that project maintainers regularly review webhook settings and URLs to ensure they are configured correctly and point to secure, trusted endpoints.

For further information on CVE-2022-4054, please refer to the following resources

1. GitLab Security Release: 15.4.6, 15.5.5, and 15.6.1
2. CVE-2022-4054 - NVD - National Vulnerability Database
3. GitLab Webhooks Documentation

In conclusion, vulnerabilities like CVE-2022-4054 highlight the importance of continually monitoring software for security issues, applying patches as soon as they become available, and being proactive in addressing potential risks. By staying informed and taking the appropriate steps, users can help protect their GitLab projects and maintain the integrity of their repositories.

Timeline

Published on: 01/26/2023 21:18:00 UTC
Last modified on: 02/01/2023 17:22:00 UTC