Package Instance

Improper Authentication
In Symfony, a vulnerability would allow an attacker to authenticate as a privileged user on sites with user registration and remember me login functionality enabled.

Prevent user enumeration using Guard or the new Authenticator-based Security
Description
-----------

The ability to enumerate users was possible without relevant permissions due to different exception messages depending on whether the user existed or not. It was also possible to enumerate users by using a timing attack, by comparing time elapsed when authenticating an existing user and authenticating a non-existing user.

Resolution
----------

We now ensure that 403s are returned whether the user exists or not if the password is invalid or if the user does not exist.

The patch for this issue is available [here](https://github.com/symfony/symfony/commit/2a581d22cc621b33d5464ed65c4bc2057f72f011) for branch 3.4.

Credits
-------

I would like to thank James Isaac and Mathias Brodala for reporting the issue and Robin Chalas for fixing the issue.

URL Redirection to Untrusted Site (Open Redirect)
By using backslashes in the `_failure_path` input field of login forms, an attacker can work around the redirection target restrictions and effectively redirect the user to any domain after login.