CVE-2024-55603 Information

Description

Kanboard is project management software that focuses on the Kanban methodology. In affected versions sessions are still usable even though their lifetime has exceeded. Kanboard implements a cutom session handler (app/Core/Session/SessionHandler.php) to store the session data in a database. Therefore when a session_id is given kanboard queries the data from the sessions sql table. At this point it does not correctly verify if a given session_id has already exceeded its lifetime (expires_at). Thus a session which’s lifetime is already > time() is still queried from the database and hence a valid login. The implemented SessionHandlerInterface::gc function that does remove invalid sessions is called only with a certain probability (Cleans up expired sessions. Called by session_start() based on session.gc_divisor session.gc_probability and session.gc_maxlifetime settings) accordingly to the php documentation. In the official Kanboard docker image these values default to: session.gc_probability=1 session.gc_divisor=1000. Thus an expired session is only terminated with probability 1/1000. This issue has been addressed in release 1.2.43 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

Reference

https://github.com/kanboard/kanboard/blob/main/app/Core/Session/SessionHandler.php#L40 https://github.com/kanboard/kanboard/commit/7ce61c34d962ca8b5dce776289ddf4b207be6e78 https://github.com/kanboard/kanboard/security/advisories/GHSA-gv5c-8pxr-p484 https://www.php.net/manual/en/function.session-start.php https://www.php.net/manual/en/session.configuration.php#ini.session.gc-divisor https://www.php.net/manual/en/session.configuration.php#ini.session.gc-maxlifetime https://www.php.net/manual/en/session.configuration.php#ini.session.gc-probability https://www.php.net/manual/en/sessionhandlerinterface.gc.php