Description
Opera cannot properly restrict modifications to cookies established in HTTPS sessions, which allows man-in-the-middle attackers to overwrite or delete arbitrary cookies via a Set-Cookie header in an HTTP response, related to lack of the HTTP Strict Transport Security (HSTS) includeSubDomains feature, aka a "cookie forcing" issue.
References
- http://michael-coates.blogspot.com/2010/01/cookie-forcing-trust-your-cookies-no.html
- http://code.google.com/p/browsersec/wiki/Part2#Same-origin_policy_for_cookies
- http://scarybeastsecurity.blogspot.com/2011/02/some-less-obvious-benefits-of-hsts.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=660053
- http://scarybeastsecurity.blogspot.com/2008/11/cookie-forcing.html