How does CVE-2022-51026 allow unauthenticated GitLab impersonation in Bytebase?

The short version

• Unauthenticated attackers can bypass login requirements in vulnerable Bytebase installations.
• The vulnerability stems from trusting client-supplied configuration data in a specific API endpoint.
• Successful exploitation allows session token issuance for any chosen email address.

The details

According to the National Vulnerability Database, CVE-2022-51026 carries a critical severity rating of 9.3. This vulnerability exists in Bytebase versions 0.12.0 and all subsequent releases prior to version 1.0.1. The issue is classified under CWE-290, which relates to improper handling of authentication mechanisms. The flaw specifically resides within the POST /api/auth/login/GITLAB_SELF_HOST endpoint. This endpoint is designed to handle authentication requests from self-hosted GitLab providers. However, the application incorrectly trusts configuration data supplied by the client during the login process.

The context

Attackers exploit this trust by setting the instanceUrl parameter to a server they control. This external server is configured to return an active user record with an email address of the attacker's choosing. Bytebase processes this response without sufficient validation. Consequently, the application issues valid session tokens for the specified principal. This mechanism allows an unauthenticated actor to impersonate any existing user within the system.

Next steps

Organisations running Bytebase versions before 1.0.1 are exposed to this remote authentication bypass. The vulnerability allows attackers to assume the identity of high-privileged accounts, including the Owner role. Furthermore, attackers can create new members within the affected environment. Since the flaw permits full impersonation, compromised accounts can perform any action permitted by their role. Version 1.0.1 is identified as the release that addresses this issue.

What defenders should look for

Teams usually monitor for unusual login patterns from unexpected IP addresses or geographic locations. Check whether session tokens are being issued for users who have not recently attempted to log in via standard methods. Look for discrepancies between the source of authentication requests and the expected identity provider endpoints. Investigate any sudden changes to user roles or permissions, especially for administrative accounts. Containment moves often involve revoking active sessions for affected users and forcing password resets. Reviewing server logs for requests to the specific GitLab self-host endpoint can reveal exploitation attempts.

What to do and how to stay safe: Bytebase

• Verify your Bytebase version and confirm if it is prior to 1.0.1.
• Monitor authentication logs for requests to the GITLAB_SELF_HOST endpoint from untrusted sources.
• Restrict network access to the Bytebase API endpoints to prevent unauthenticated external access.
• Upgrade to version 1.0.1 or later to apply the vendor-provided fix.

Step-by-step guide: How Virtual Patching Works: The Mechanics Behind Inline Protection

General security guidance from the Honeypot Daily newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

Which Bytebase versions are affected by CVE-2022-51026?

Versions 0.12.0 and all releases before 1.0.1 are affected by this authentication bypass vulnerability.

What is the severity rating of this vulnerability?

The National Vulnerability Database rates CVE-2022-51026 as critical with a CVSS score of 9.3.

How do attackers exploit this flaw?

Attackers supply a malicious instanceUrl to a controlled server, which returns a chosen email to bypass authentication.