Maildrop: privilege escalation

Background

maildrop is the mail filter/mail delivery agent that is used by the Courier Mail Server.

Description

Christoph Anton Mitterer reported that maildrop does not properly drop its privileges when run as root.

Impact

A local attacker could create a specially crafted .mailfilter file, possibly leading to the execution of arbitrary commands with the “root” group privileges. NOTE: Successful exploitation requires that maildrop is run as root with the -d option.

Workaround

There is no known workaround at this time.

Resolution

All maildrop users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=mail-filter/maildrop-2.4.2"