Werk #14482: Use proper HMAC for cookie signing
|Title||Use proper HMAC for cookie signing|
|Date||Aug 2, 2022|
|Checkmk Edition||Checkmk Raw (CRE)|
|Compatibility||Incompatible - Manual interaction might be required|
Previously to this Werk the Session cookies were signed with with calculating a SHA256 hash over username, session id, a serial plus a secret. This could in theory lead to a "partial message collision".
Since we parse the data given in the cookie and test for validity, we are confident that such an attack is not possible. But to be future-proof we switch to proper HMAC for signing the cookie value. This will invalidate all session cookies for a site. Therefore all users have to reauthenticate to retrieve new valid cookies.