---

Introduction

In this post, we discuss a recently discovered issue in GitLab CE/EE, tracked as CVE-2024-1816. The vulnerability affects all GitLab CE/EE versions starting from 12. before 16.11.5, 17. before 17..3, and 17.1 before 17.1.1. The flaw allows an attacker to cause a Denial of Service (DoS) by crafting a specific OpenAPI file. In the following sections, we will provide an overview of OpenAPI, the affected GitLab components, and details on the exploit, including original references and code snippets.

OpenAPI Background

OpenAPI is a specification for Machine-readable interface files, allowing automated tools and libraries to comprehend the capabilities of an API. Typically written in JSON or YAML format, OpenAPI documents enable clearer documentation, better code generation, and improved testing capabilities. For more information on OpenAPI, please visit the official website.

Affected GitLab Components

GitLab is a web-based DevOps platform that provides a range of features, including source code management, continuous integration/delivery, and issue tracking. The Denial of Service vulnerability in question affects GitLab Community Edition (CE) and GitLab Enterprise Edition (EE) in the discussed version ranges.

Exploit Details

The vulnerability stems from the way GitLab handles OpenAPI files in certain scenarios. By using a crafted OpenAPI file, an attacker can trigger a DoS, causing the GitLab service to become unresponsive and negatively impacting all users. Below, we provide an overview of the exploit and a code snippet to help illustrate the issue.

Crafting the OpenAPI File

The attacker needs to create a crafted OpenAPI file that will exploit the vulnerability in GitLab. This file should contain malformed data, triggering the flaw when GitLab processes it. A sample code snippet of the crafted OpenAPI file is provided below:

openapi: "3.."
info:
  version: "1.."
  title: "CVE-2024-1816 Exploit"
servers:
  - url: "https://vulnerable.gitlab.instance.com";
paths:
  /trigger-dos:
    get:
      summary: "Trigger CVE-2024-1816 Vulnerability"
      operationId: "triggerDoS"
      responses:
        "200":
          description: "Success"
          content:
            'application/json': ...

>Note: The provided code snippet is for demonstration purposes only and might not represent a fully functional exploit. Do not attempt to use this code in unauthorized or malicious contexts.

Exploiting the Vulnerability

While we are not providing the complete step-by-step process of exploiting this vulnerability, an attacker might perform the following steps to exploit CVE-2024-1816 effectively:

Identify a vulnerable GitLab instance.

2. Authenticate to the GitLab instance, ensuring they have the required permissions to import/manage OpenAPI files.

Trigger the processing of the crafted OpenAPI file by GitLab.

5. Observe the GitLab instance experiencing a DoS, becoming unresponsive, or exhibiting other negative impacts.

Original References

The vulnerability is tracked as CVE-2024-1816. For more information on the issue and affected versions, you can consult the official CVE entry, the GitLab Security Advisory, and the National Vulnerability Database (NVD) entry.

Conclusion

The CVE-2024-1816 vulnerability in GitLab CE/EE showcases the importance of assessing third-party components, such as OpenAPI files, in regard to their potential impact on security. If you are running an affected version of GitLab, it is advised that you update to a patched version as soon as possible to mitigate the risk. Staying up-to-date with security advisories and timely patching can help prevent issues like this in the future.

Timeline

Published on: 06/27/2024 00:15:10 UTC
Last modified on: 06/28/2024 13:23:54 UTC