Some weaknesses have been reported in SquirrelMail, which can be exploited by malicious users to disclose certain system information and by malicious people to cause a DoS (Denial of Service).

1) The Mail Fetch plugin allows users to specify arbitrary ports in their POP accounts settings, which can be exploited to perform port scans within potentially restricted networks.

Successful exploitation requires authentication and that the Mail Fetch plugin is enabled.

2) The login mechanism accepts random logins with 8-bit characters in the password and creates a new preference file if it does not exist yet. This can be exploited to use up disk space by e.g. logging in with various random user names and creating a large amount of preference files.

Note: This can not be exploited to bypass the login mechanism and e.g. perform actions requiring valid user credentials.

The weaknesses are reported in version 1.4.20. Prior versions may also be affected.

Solution
Update to version 1.4.21.

Provided and/or discovered by
1) TEHTRI-Security
2) The vendor credits Mikhail Goriachev

Changelog
Further details available to Secunia VIM customers

Original Advisory
1) http://www.squirrelmail.org/security/issue/2010-06-21
2) http://www.squirrelmail.org/security/issue/2010-07-23

Deep Links
Links available to Secunia VIM customers