SquirrelMail: Encoded text XSS vulnerability

Background

SquirrelMail is a webmail package written in PHP. It supports IMAP and SMTP, and can optionally be installed with SQL support.

Description

SquirrelMail fails to properly sanitize certain strings when decoding specially-crafted headers.

Impact

By enticing a user to read a specially-crafted e-mail, an attacker can execute arbitrary scripts running in the context of the victim’s browser. This could lead to a compromise of the user’s webmail account, cookie theft, etc.

Workaround

There is no known workaround at this time.

Resolution

All SquirrelMail users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=mail-client/squirrelmail-1.4.3a-r2"

Note: Users with the vhosts USE flag set should manually use webapp-config to finalize the update.