2015-06-20 A fast-changing security world
At work I reviewed something about TLS security I wrote in May 2014 and noticed I had to make some serious adjustments for the May 2015 state. SSLv3 is no longer accepted, SHA1 is no longer an accepted hashing algorithm and other changes. This week on the home server greenblatt I had two different impacts from the latest OpenSSL update: SSL communications with the Fritz!Box was failing and SSL in sendmail was failing, both due to the latest insights into the security of the Diffie-Hellman key exchange. These insights are very very new: in April I did a course in the Certified Information Systems Security Professional (CISSP) common body of knowledge and I learned the default Diffie-Hellman parameters were safe. Now we learn to generate them for each individual system at the same strength as the private key. Knowledge of cryptographic quality ages fast at the moment.