Some vulnerabilities have been reported in the SquirrelMail G/PGP Encryption Plugin, which can be exploited by malicious users to delete and overwrite certain files, by malicious people to conduct script insertion attacks, and by malicious users and malicious people to disclose sensitive information or to compromise a vulnerable system.

1) An input validation error exists in the "deleteKey()" function, which can be exploited by to inject and execute arbitrary shell commands via the "fpr" parameter.

Successful exploitation of this vulnerability requires valid user credentials.

2) An input validation error exists in the "gpg_check_sign_pgp_mime()" function, which can be exploited to inject and execute arbitrary shell commands via the "messageSignedText" variable when a users opens a specially crafted email.

3) An input validation error exists in the "gpg_recv_key()" function in gpg_key_functions.php, which can be exploited to inject and execute arbitrary shell commands via the "keyserver" parameter.

Successful exploitation of this vulnerability requires valid user credentials.

4) Input passed to the "help" parameter in gpg_help.php and gpg_help_base.php is not properly verified before being used to include files. This can be exploited to include arbitrary files from local resources.

5) Certain input is not properly verified before being used, which can be exploited by malicious users to delete or overwrite certain files.

6) The function "gpg_import_link()" in gpg_hook_functions.php does not properly sanitise certain input before returning it to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site if a malicious email is viewed.

The vulnerabilities #1-4 are reported in version 2.0. Vulnerabilities #1 and #3 are also reported in version 2.1. Vulnerabilities #5 and #6 are reported in version 2.0, 2.0.1, and 2.1. Other versions may also be affected.

Solution
Update to version 2.1 and grant only trusted users web access to the application. Edit the source code to ensure that input is properly sanitised.

Provided and/or discovered by
1-4) An anonymous person, reported via iDefense.
5, 6) Tomas Kuliavas

Changelog
Further details available to Secunia VIM customers

Original Advisory
1) http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=329
2) http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=330
3) http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=331
4) http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=555

5, 6) http://www.topolis.lt/bugtraq/

Deep Links
Links available to Secunia VIM customers