OpenVPN: Multiple vulnerabilities

Background

OpenVPN is a multi-platform, full-featured SSL VPN solution.

Description

The OpenVPN client contains a format string bug in the handling of the foreign_option in options.c. Furthermore, when the OpenVPN server runs in TCP mode, it may dereference a NULL pointer under specific error conditions.

Impact

A remote attacker could setup a malicious OpenVPN server and trick the user into connecting to it, potentially executing arbitrary code on the client’s computer. A remote attacker could also exploit the NULL dereference issue by sending specific packets to an OpenVPN server running in TCP mode, resulting in a Denial of Service condition.

Workaround

Do not use “pull” or “client” options in the OpenVPN client configuration file, and use UDP mode for the OpenVPN server.

Resolution

All OpenVPN users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-misc/openvpn-2.0.4"