getmail: Filesystem overwrite vulnerability

Background

getmail is a reliable fetchmail replacement that supports Maildir, Mboxrd and external MDA delivery.

Description

David Watson discovered a vulnerability in getmail when it is configured to run as root and deliver mail to the maildirs/mbox files of untrusted local users. A malicious local user can then exploit a race condition, or a similar symlink attack, and potentially cause getmail to create or overwrite files in any directory on the system.

Impact

An untrusted local user could potentially create or overwrite files in any directory on the system. This vulnerability may also be exploited to have arbitrary commands executed as root.

Workaround

Do not run getmail as a privileged user; or, in version 4, use an external MDA with explicitly configured user and group privileges.

Resolution

All getmail users should upgrade to the latest version:

 # emerge sync
 
 # emerge -pv ">=net-mail/getmail-4.2.0"
 # emerge ">=net-mail/getmail-4.2.0"