CSRF Protection

CSRF checks for HTTP request

When considering HTTP request safety from the TeamCity perspective, the following checks are sequentially made:

1. If an HTTP request is a non-modifying one (such as GET), it is considered safe.

2. If an HTTP request has a secure CSRF token either in the parameter or in the HTTP header and this token matches the one stored in user session, it is considered safe.

Implications for non-browser HTTP clients

For non-browser API access, we recommend using token-based authentication.

Implications for CORS clients

To use CORS request, configure the CORS support as described here. This configuration will be enough for GET requests.
If you need to send POST/PUT/DELETE requests via CORS, you should obtain a CSRF token using the authenticationTest.html?csrf call, and then provide this token with your modifying HTTP requests.

Troubleshooting

If you face problems regarding CSRF protection in TeamCity (for example, you get the " Responding with 403 status code due to failed CSRF check " response from the server), you can try these steps:

• Enforce verification of Origin/Referer headers for CORS operations by setting the teamcity.csrf.paranoid=false internal property, similarly to how it worked in TeamCity versions prior to 2020.1 (read our Upgrade Notes) for more details).

• Temporary disable CSRF protection at all by setting the teamcity.csrf.origin.check.enabled=logOnly internal property.

• Information about failed CSRF attempts is logged into TeamCity/logs/teamcity-auth.log files. For more detailed diagnostics of the requests, enable the debug-auth logging preset.

• If your "unsafe" (PUT, POST, DELETE) requests utilize access tokens to employ the Bearer authentication scheme, consider clearing your session cookies. Doing so allows TeamCity to skip validating CSRF tokens entirely.

• If your environment or scenario mandates that session cookies are present, ensure your requests are not using CSRF tokens that correspond to expired sessions. As a workaround, you may want to reuse session cookies of the first HTTP request for the following ones. To do so in cURL, use the --cookie-jar and --cookie command-line options to save and read cookies to/from a file. In addition, add the teamcity.tokenAuth.setSessionCookie=true internal property to force TeamCity to create a session (and expect session cookies for the following requests).

In case none of the listed steps help to resolve your problem, please contact our support and provide your teamcity-auth.log logs with the enabled teamcity-auth logging preset.