Debian: DSA-2548-1 Medium Severity: Mitigations for Tor DoS Attack

Severel vulnerabilities have been discovered in Tor, an online privacy
tool.

CVE-2012-3518

Avoid an uninitialised memory read when reading a vote or consensus
document that has an unrecognized flavour name. This could lead to
a remote, resulting in denial of service.

CVE-2012-3519

Try to leak less information about what relays a client is choosing to
a side-channel attacker.

CVE-2012-4419

By providing specially crafted date strings to a victim tor instance,
an attacker can cause it to run into an assertion and shut down

Additionally the update to stable includes the following fixes:
- - When waiting for a client to renegotiate, don't allow it to add any
bytes to the input buffer. This fixes a potential DoS issue
[tor-5934, tor-6007].

For the stable distribution (squeeze), these problems have been fixed in
version 0.2.2.39-1.

For the unstable distribution, these problems have been fixed in version
0.2.3.22-rc-1.

We recommend that you upgrade your tor packages.

Further information abou...