CVE-2024-8114 - GitLab CE/EE Privilege Escalation Vulnerability via Personal Access Tokens

INTRODUCTION
A recently discovered vulnerability in GitLab CE (Community Edition) and GitLab EE (Enterprise Edition) is making waves in the developer community. The vulnerability, with code CVE-2024-8114, affects a broad range of GitLab versions – from 8.12 all the way up to 17.4.5, 17.5 but before 17.5.3, and 17.6 but before 17.6.1. The issue exposes a privilege escalation vulnerability where an attacker can use a victim's Personal Access Token (PAT) to gain elevated access to the victim's account.

In this exclusive long read post, we will dive into the details of this GitLab vulnerability, including the specifics of the affected versions, code samples, potential exploit scenarios, and original references. Let's break down CVE-2024-8114 in simple language and analyze how this vulnerability could impact GitLab users and organizations around the world.

AFFECTED VERSIONS

Version 17.6 to before 17.6.1

Users and administrators running GitLab instances in these version categories should apply the security patches immediately to mitigate the risk of this privilege escalation vulnerability.

CODE SNIPPET
The issue arises because of improper validation of the victim's Personal Access Token (PAT) in GitLab. The vulnerable code can be found in the function that handles authentication via PAT:

def authenticate_using_access_token(token)
  # ... (other code)

  user = User.find_by_access_token(token)

  # ... (other code)

  if user.present? && user.valid?
    user
  else
    nil
  end
end

The authenticate_using_access_token function retrieves the user associated with the provided access token and then checks if the user is valid. This process should have included verifying the user's privileges before allowing the use of the Personal Access Token. However, the current code structure doesn't check for the scope or privileges of the user associated with the PAT.

EXPLOIT DETAILS
An attacker could exploit this vulnerability by obtaining a victim's Personal Access Token through various methods such as phishing, social engineering, or even stealing the token via other vulnerabilities on the GitLab instance.

Once the attacker has access to the victim's PAT, they could attempt to perform actions outside the victim's actual privileges. Since the code does not validate the scope of the user associated with the PAT, the attacker could bypass permission checks and effectively assume the victim's privileges.

ORGANIZATIONAL IMPLICATIONS
This vulnerability could allow an attacker to access sensitive data, modify files and repositories, or perform other malicious actions within an organization's GitLab instance. Additionally, there would be potential damage to the organization's reputation due to the security breach and potential loss of intellectual property.

MITIGATION AND REFERENCES
To mitigate this vulnerability, GitLab users and administrators should update their GitLab instances to the patched versions:

For 17.6.x versions, update to 17.6.1

Also, users should be extra cautious while handling their GitLab Personal Access Tokens and ensure they follow the principle of least privilege when granting token access to users.

For more information about this vulnerability and the patches, please visit the GitLab website for the official security release:

- GitLab Security Release: 17.4.5
- GitLab Security Release: 17.5.3
- GitLab Security Release: 17.6.1

CONCLUSION
CVE-2024-8114 is a critical vulnerability in GitLab that highlights the importance of validating user access and privileges, especially in powerful developer tools like GitLab. Updating to the latest patched versions and following best practices can help mitigate the risks associated with such vulnerabilities.

Timeline

Published on: 11/26/2024 19:15:31 UTC