Proxytunnel: Format string vulnerability

Background

Proxytunnel is a program that tunnels connections to a remote server through a standard HTTPS proxy.

Description

Florian Schilhabel of the Gentoo Linux Security Audit project found a format string vulnerability in Proxytunnel. When the program is started in daemon mode (-a [port]), it improperly logs invalid proxy answers to syslog.

Impact

A malicious remote server could send specially-crafted invalid answers to exploit the format string vulnerability, potentially allowing the execution of arbitrary code on the tunnelling host with the rights of the Proxytunnel process.

Workaround

You can mitigate the issue by only allowing connections to trusted remote servers.

Resolution

All Proxytunnel users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-misc/proxytunnel-1.2.3"