It was discovered that PyOpenSSL, a Python wrapper around the OpenSSL library, does not properly handle certificates with NULL characters in the Subject Alternative Name field. A remote attacker in the position to obtain a certificate for 'www.foo.org\0.example.com' from a CA that a SSL client trusts, could use this to spoof www.foo.org and conduct man-in-the-middle attacks between the PyOpenSSL-using client and the SSL server.

For the oldstable distribution (squeeze), this problem has been fixed in version 0.10-1+squeeze1. For the stable distribution (wheezy), this problem has been fixed in version 0.13-2+deb7u1. For the unstable distribution (sid), this problem has been fixed in version 0.13-2.1. We recommend that you upgrade your pyopenssl packages.

pyopenssl is a high-level wrapper around a subset of the OpenSSL library.

pyopenssl on Debian Linux

This check tests the installed software version using the apt package manager.

• http://www.debian.org/security/2013/dsa-2763.html

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Updated on 2015-03-25