Surf Jack - HTTPS will not save you
Say hello to a new security tool called Surf Jack which demonstrates a security flaw found in many public sites. The proof of concept tool allows testers to steal session cookies on HTTP and HTTPS sites that do not set the Cookie secure flag. I've been working with two banks and some of the vulnerable sites to get this fixed before publishing my research. Mike Perry gave a talk at Defcon involving the exact same vulnerability - so there is no point in keeping this from the public.
The following is a video demonstration of how this affects Gmail and how to prevent this from affecting your you.