Ubuntu Security Notice 612-4 – USN-612-1 fixed vulnerabilities in openssl. This update provides the corresponding updates for ssl-cert — potentially compromised snake-oil SSL certificates will be regenerated. A weakness has been discovered in the random number generator used by OpenSSL on Debian and Ubuntu systems. As a result of this weakness, certain encryption keys are much more common than they should be, such that an attacker could guess the key through a brute-force attack given minimal knowledge of the system. This particularly affects the use of encryption keys in OpenSSH, OpenVPN and SSL certificates. This vulnerability only affects operating systems which (like Ubuntu) are based on Debian. However, other systems can be indirectly affected if weak keys are imported into them.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/66395/USN-612-4.txt
Source: https://packetstormsecurity.com/files/66395/Ubuntu-Security-Notice-612-4.html