Re: squirrelmail CSRF vulnerability

[Tim Newsham <newsham () lava net>]

> > II. Application should use CSRF token which is random enough to identify 
> > every legitimate post login request.
>
> According to: http://squirrelmail.org/security/issue/2006-12-02 version
> 1.4.8-4 is vulnerable to a XSS vulnerability, so an attacker could use the
> XSS vector to grab the session token ("CSRF token") and continue the CSRF 
> attack.

This might just be semantics:  I wouldn't consider the XSS attack to be a 
CSRF attack.  The XSS script runs in the same context that the user or any 
legitimate script running on behalf of the user runs.  When it makes a 
reference, it has access to things like the CSRF token.  It's not forging 
a reference.  It's creating one in the same way as any legitimate script 
action would.

summary:
  CSRF - forging a reference blindly.
  XSS script - acting on behalf of the user after same-origin policy
       protections have been compromised

> - Josh

Tim Newsham
http://www.thenewsh.com/~newsham/