DenyHosts: Denial of service

Background

DenyHosts is a script intended to be run by Linux system administrators to help thwart SSH server attacks.

Description

DenyHosts does not properly define the regular expressions used when parsing SSH authentication logs.

Impact

A remote attacker could possibly cause a Denial of Service condition via a crafted login name.

Workaround

There is no known workaround at this time.

Resolution

All DenyHost users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=app-admin/denyhosts-2.6-r9"