OpenSSL Key Recovery Attack on DH small subgroups (CVE-2016-0701)

Usual Mandatory Disclaimer: IANAC I am not a cryptographer so I might likely end up writing a bunch of mistakes in this blog post... tl;dr The OpenSSL 1.0.2 releases suffer from a Key Recovery Attack on DH small subgroups. This issue got assigned CVE-2016-0701 with a severity of High and OpenSSL...

Vulnerability in OpenSSL - DH small subgroups

Historically OpenSSL usually only ever generated DH parameters based on “safe” primes. More recently in version 1.0.2 support was provided for generating X9.42 style parameter files such as those required for RFC 5114 support. The primes used in such files may not be “safe”. Where an application ...