LibVNCServer: Authentication bypass

Background

LibVNCServer is a GPL’ed library for creating VNC servers.

Description

LibVNCServer fails to properly validate protocol types effectively letting users decide what protocol to use, such as “Type 1 - None”. LibVNCServer will accept this security type, even if it is not offered by the server.

Impact

An attacker could use this vulnerability to gain unauthorized access with the privileges of the user running the VNC server.

Workaround

There is no known workaround at this time.

Resolution

All LibVNCServer users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-libs/libvncserver-0.8.2"