Yeah, I see. So the 'authenticity_token' they have is can still be eavesdropped but will prevent, as you say, browser GET/POST requests. But to 'insert' a img tag, hidden iframe etc, doesn't the attacker have to be "in the middle" anyway?
On Fri, Nov 20, 2009 at 7:52 PM, Knight, Brandon <[email protected]> wrote: > CSRF tokens are not used to protect against man-in-the-middle attacks. If > somebody can MITM they can see and do whatever they want to your HTTP > requests and/or responses. > > A CSRF token is designed to protect against a remote attack where somebody > forces a victim's browser to GET/POST a request to the site they are > targeting. This can be done by using img tags, hidden iframes, etc to > obscure this secondary request form being noticed by the victim. The CSRF > token is available only within the DOM(or in cookies) of the site it is > placed on and, given good design and enforcement of the same origin policy, > should only be known to the user of the site and the site itself. The only > way, as an attacker, to obtain it would be either through brute force, > exploiting poor design such as weakly selected tokens, or potentially > through poor trust relationships such as exploiting third party javascript > running on the site. > > Make sense? > > -Brandon > > On Nov 20, 2009, at 4:38 PM, Soft Reset wrote: > > Makes sense if the connection protected the token. According to Wikipedia, > > > "Requiring a secret, user-specific token in all form submissions prevents > CSRF; the attacker's site can't put the right token in its > submissions.<http://en.wikipedia.org/wiki/Cross-site_request_forgery#cite_note-Shiflett-0> > [1]" > > But if the form Twitter returns (containing the token) is returned over > HTTP (which it is), the token is not secret and does not need to be > predicted...just eavesdropped. > > Does this sound right or am I way off and misunderstanding the whole > concept of XSRFs? > > --sr6 > > On Fri, Nov 20, 2009 at 3:23 PM, Chris Biettchert < > [email protected]> wrote: > >> The authenticity_token is used for for xsrf protection. It works as >> intended as long as it can not be predicted for another user. >> >> On Fri, Nov 20, 2009 at 10:36 AM, Soft Reset <[email protected]>wrote: >> >>> I just noticed it and was wondering if anyone else had. Twitter has >>> their "authenticity_token" as a 'hidden' input on forms...including password >>> changes, resets, etc. Anyone tried hijacking a twitter login to verify this >>> is bad form (no pun intended)? Don't want to re-invent the wheel if someone >>> already did it. >>> >>> If someone has tried it successfully, has it been brought up to the >>> twitter folks as a push for full SSL sessions? (yeah, I know SSL is also >>> having issues at the moment, but still...) >>> >>> --sr6 >>> >>> _______________________________________________ >>> Pauldotcom mailing list >>> [email protected] >>> http://mail.pauldotcom.com/cgi-bin/mailman/listinfo/pauldotcom >>> Main Web Site: http://pauldotcom.com >>> >> >> >> _______________________________________________ >> Pauldotcom mailing list >> [email protected] >> http://mail.pauldotcom.com/cgi-bin/mailman/listinfo/pauldotcom >> Main Web Site: http://pauldotcom.com >> > > _______________________________________________ > Pauldotcom mailing list > [email protected] > http://mail.pauldotcom.com/cgi-bin/mailman/listinfo/pauldotcom > Main Web Site: http://pauldotcom.com > > > > _______________________________________________ > Pauldotcom mailing list > [email protected] > http://mail.pauldotcom.com/cgi-bin/mailman/listinfo/pauldotcom > Main Web Site: http://pauldotcom.com >
_______________________________________________ Pauldotcom mailing list [email protected] http://mail.pauldotcom.com/cgi-bin/mailman/listinfo/pauldotcom Main Web Site: http://pauldotcom.com
