Headline
CVE-2023-46733: Possible session fixation
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Starting in versions 5.4.21 and 6.2.7 and prior to versions 5.4.31 and 6.3.8, SessionStrategyListener does not migrate the session after every successful login. It does so only in case the logged in user changes by means of checking the user identifier. In some use cases, the user identifier doesn’t change between the verification phase and the successful login, while the token itself changes from one type (partially-authenticated) to another (fully-authenticated). When this happens, the session id should be regenerated to prevent possible session fixations, which is not the case at the moment. As of versions 5.4.31 and 6.3.8, Symfony now checks the type of the token in addition to the user identifier before deciding whether the session id should be regenerated.
Description
SessionStrategyListener does not always migrate the session after a successful login. It only migrate the session when the logged-in user identifier changes. In some use cases, the user identifier doesn’t change between the verification phase and the successful login, while the token itself changes from one type (partially-authenticated) to another (fully-authenticated). When this happens, the session id should be regenerated to prevent possible session fixations.
Resolution
Symfony now checks the type of the token in addition to the user identifier before deciding whether the session id should be regenerated.
The patch for this issue is available here for branch 5.4.
Credits
We would like to thank Robert Meijers for reporting the issue and providing the fix.
Related news
### Description SessionStrategyListener does not always migrate the session after a successful login. It only migrate the session when the logged-in user identifier changes. In some use cases, the user identifier doesn't change between the verification phase and the successful login, while the token itself changes from one type (partially-authenticated) to another (fully-authenticated). When this happens, the session id should be regenerated to prevent possible session fixations. ### Resolution Symfony now checks the type of the token in addition to the user identifier before deciding whether the session id should be regenerated. The patch for this issue is available [here](https://github.com/symfony/symfony/commit/dc356499d5ceb86f7cf2b4c7f032eca97061ed74) for branch 5.4. ### Credits We would like to thank Robert Meijers for reporting the issue and providing the fix.