Dovecot: Privilege Escalation

Background

Dovecot is an open source IMAP and POP3 email server.

Description

A vulnerability has been discovered in Dovecot. Please review the CVE identifier referenced below for details.

Impact

When two passdb configuration entries exist in Dovecot configuration, which have the same driver and args settings, the incorrect username_filter and mechanism settings can be applied to passdb definitions. These incorrectly applied settings can lead to an unintended security configuration and can permit privilege escalation with certain configurations involving master user authentication. Dovecot documentation does not advise against the use of passdb definitions which have the same driver and args settings. One such configuration would be where an administrator wishes to use the same pam configuration or passwd file for both normal and master users but use the username_filter setting to restrict which of the users is able to be a master user.

Workaround

There is no known workaround at this time.

Resolution

All Dovecot users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-mail/dovecot-2.3.19.1-r1"