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j_86 · #1 10-02-2009, 07:19 PM

vBulletin stores two cookies - a hashed password and my user ID. If someone steals these two cookies from me (i.e. if my cookies were stolen via an XSS flaw in the vB installation), would they be able to cleanly authenticate into my user account?

BSMedia · #2 10-02-2009, 07:50 PM

No.

Though anything is possible

James Birkett · #3 10-02-2009, 09:50 PM

Considering a lot of the forum requires reauthentication - no.
The cookie is hashed using your cookie ID as well as your password and salt, triple hash whereas the database is a double hash.

j_86 · #4 10-03-2009, 04:14 PM

Quote:

Originally Posted by James Birkett

Considering a lot of the forum requires reauthentication - no.

This doesn't answer my question.

Try this:

1) Login to vbulletin.org

2) Delete the cookies highlighted below:

3) Close your browser completely (ending any authentication sessions)

4) Visit vbulletin.org

5) You are re-authenticated

So, surely this means that vBulletin is reauthenticating you based on your hashed password value (it doesn't matter how it is hashed) and your user ID.

This means that should vbulletin.org be attacked via an XSS flaw, an attacker could load an iframe on vbulletin.org of a malicious website and steal my cookie, using it to cleanly authenticate.

Are my assumptions here correct?

j_86 · #5 10-15-2009, 10:15 AM

I've tested this, and it looks like by taking the cookie information, anyone can authenticate as you. Whether or not the password is hashed is irrelevant and ultimately futile against XSS attacks

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