Tor: Multiple vulnerabilities

Background

Tor is an implementation of second generation Onion Routing, a connection-oriented anonymizing communication service.

Description

Multiple vulnerabilities have been discovered in Tor:

• When configured as client or bridge, Tor uses the same TLS certificate chain for all outgoing connections (CVE-2011-2768).
• When configured as a bridge, Tor relays can distinguish incoming bridge connections from client connections (CVE-2011-2769).
• An error in or/buffers.c could result in a heap-based buffer overflow (CVE-2011-2778).

Impact

A remote attacker could possibly execute arbitrary code or cause a Denial of Service. Furthermore, a remote relay the user is directly connected to may be able to disclose anonymous information about that user or enumerate bridges in the user’s connection.

Workaround

There is no known workaround at this time.

Resolution

All Tor users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-misc/tor-0.2.2.35"