CVE-2022-3285 is a recently discovered security vulnerability that affects specific versions of GitLab, a web-based DevOps life cycle tool that allows teams to collaborate on code and manage version control. This vulnerability allows an unauthorized attacker to bypass the healthcheck endpoint allow list and prevent access to GitLab. In this post, we’ll discuss the affected versions, the potential impact of this vulnerability, and steps you can take to mitigate it.
Affected GitLab Versions
The vulnerability affects all versions from 12. prior to 15.2.5, 15.3 prior to 15.3.4, and 15.4 prior to 15.4.1. If you are using any of these versions, it's highly recommended to upgrade to a patched version immediately. The GitLab Security Advisory can be found here: GitLab Security Release: 15.4.1, 15.3.4, and 15.2.5.
The Exploit Details
The healthcheck endpoint is an essential monitoring tool to ensure the availability and responsiveness of GitLab services. However, CVE-2022-3285 allows an attacker to bypass the healthcheck endpoint allow list restrictions. As a result, unauthorized users can execute denial-of-service (DoS) attacks on the target GitLab server, potentially bringing down key services and preventing authorized users from accessing GitLab.
The vulnerability lies in how the healthcheck allow list is processed. To exploit this, an attacker can craft a malicious request to GitLab healthcheck endpoints that bypasses the restrictions and renders the server unresponsive. An example of this malicious request is shown below:
GET /-/healthcheck HTTP/1.1
Host: target-gitlab-server.com
X-Forwarded-For: 1.2.3.4, restricted-ip-address
In this example, the attacker forges the X-Forwarded-For header to include a restricted IP address, causing the healthcheck allow list check to fail. The server then processes the request as coming from an unauthorized user and blocks access to the healthcheck endpoints.
Mitigation
To prevent unauthorized access to the healthcheck endpoint and protect your GitLab servers against the potential impact of CVE-2022-3285, you should take the following steps:
1. Upgrade to a patched version of GitLab: Update your GitLab version to one of the following patched versions as mentioned in the GitLab Security Release: 15.2.5, 15.3.4, or 15.4.1, depending on your current version. This will address the vulnerability and ensure your server is protected.
2. Monitor your logs for suspicious activity: Keep an eye on your GitLab server logs for any unusual or unexpected requests targeting the healthcheck endpoints. Look out for requests containing forged X-Forwarded-For header values or originating from unfamiliar IP addresses.
3. Ensure proper access control: Regularly review your network access control lists and firewall rules to ensure that only authorized users and services can access your GitLab servers. Additionally, implement strong user authentication and authorization policies to protect your servers from unauthorized access.
Conclusion
CVE-2022-3285 is a critical vulnerability in GitLab that allows attackers to bypass the healthcheck endpoint allow list and prevent access to the GitLab server. It's essential for affected users to follow the recommended mitigation steps and update their GitLab servers to a patched version as soon as possible. By doing so, you'll be better protected against potential attacks and reduce the risk of unauthorized access to your GitLab server.
Timeline
Published on: 11/09/2022 23:15:00 UTC
Last modified on: 11/11/2022 01:06:00 UTC