poppassd_pam: Unauthorized password changing

Background

poppassd_pam is a PAM-enabled server for changing system passwords that can be used to change POP server passwords.

Description

Gentoo Linux developer Marcus Hanwell discovered that poppassd_pam did not check that the old password was valid before changing passwords. Our investigation revealed that poppassd_pam did not call pam_authenticate before calling pam_chauthtok.

Impact

A remote attacker could change the system password of any user, including root. This leads to a complete compromise of the POP accounts, and may also lead to a complete root compromise of the affected server, if it also provides shell access authenticated using system passwords.

Workaround

There is no known workaround at this time.

Resolution

All poppassd_pam users should migrate to the new package called poppassd_ceti:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-mail/poppassd_ceti-1.8.4"

Note: Portage will automatically replace the poppassd_pam package by the poppassd_ceti package.