DSA-2363-1 tor -- buffer overflow

Related Vulnerabilities: CVE-2011-2778  

It was discovered that Tor, an online privacy tool, incorrectly computes buffer sizes in certain cases involving SOCKS connections. Malicious parties could use this to cause a heap-based buffer overflow, potentially allowing execution of arbitrary code. In Tor's default configuration this issue can only be triggered by clients that can connect to Tor's SOCKS port, which listens only on localhost by default. In non-default configurations where Tor's SocksPort listens not only on localhost or where Tor was configured to use another SOCKS server for all of its outgoing connections, Tor is vulnerable to a larger set of malicious parties. For the oldstable distribution (lenny), this problem has been fixed in version 0.2.1.32-1. For the stable distribution (squeeze), this problem has been fixed in version 0.2.2.35-1~squeeze+1. For the unstable (sid) and testing (wheezy) distributions, this problem has been fixed in version 0.2.2.35-1. For the experimental distribution, this problem has has fixed in version 0.2.3.10-alpha-1. We recommend that you upgrade your tor packages. Please note that the update for stable (squeeze) updates this package from 0.2.1.31 to 0.2.2.35, a new major release of Tor, as upstream has announced end-of-life for the 0.2.1.x tree for the near future. Please check your Tor runs as expected after the upgrade.

Debian Security Advisory

DSA-2363-1 tor -- buffer overflow

Date Reported:
16 Dec 2011
Affected Packages:
tor
Vulnerable:
Yes
Security database references:
In Mitre's CVE dictionary: CVE-2011-2778.
More information:

It was discovered that Tor, an online privacy tool, incorrectly computes buffer sizes in certain cases involving SOCKS connections. Malicious parties could use this to cause a heap-based buffer overflow, potentially allowing execution of arbitrary code.

In Tor's default configuration this issue can only be triggered by clients that can connect to Tor's SOCKS port, which listens only on localhost by default.

In non-default configurations where Tor's SocksPort listens not only on localhost or where Tor was configured to use another SOCKS server for all of its outgoing connections, Tor is vulnerable to a larger set of malicious parties.

For the oldstable distribution (lenny), this problem has been fixed in version 0.2.1.32-1.

For the stable distribution (squeeze), this problem has been fixed in version 0.2.2.35-1~squeeze+1.

For the unstable (sid) and testing (wheezy) distributions, this problem has been fixed in version 0.2.2.35-1.

For the experimental distribution, this problem has has fixed in version 0.2.3.10-alpha-1.

We recommend that you upgrade your tor packages.

Please note that the update for stable (squeeze) updates this package from 0.2.1.31 to 0.2.2.35, a new major release of Tor, as upstream has announced end-of-life for the 0.2.1.x tree for the near future. Please check your Tor runs as expected after the upgrade.