WebApp Sec mailing list archives

Re: Hijacking URL Encoded Session IDs using Referer Logs


From: ONEILL David J <David.J.Oneill () state or us>
Date: 25 Nov 2002 07:39:04 -0800

And ... Unless one would want to limit potential users from being able to
access the website, one would never assume that the session ID could be stored
in a cookie.

David J. O'Neill
NEDSS - IS7
Parkway Bldg., 2nd Floor
Phone: (503) 378-2101 ext. 364
FAX:     (503) 378-2102

crazybob () crazybob org 11/25/02 06:59AM >>>
Many (most?) application servers use URL encoded session IDs when the 
user has disabled cookies. Many users disable cookies as a security 
precaution. There should be an advisory on this so that application 
server vendors stop allowing URL encoded session IDs by default.

If you can post an interesting link to a site, you can hijack the 
sessions of users with cookies disabled, and no one would be the wiser.

Does hotmail or yahoo use URL session IDs? E-mail someone a link to 
your site and hijack their e-mail account. In the scope of this attack, 
they'd have no way to tell that you stole it.

Also a good reason to use HTTPS.

Bob

On Monday, November 25, 2002, at 07:48 AM, zeno wrote:

Not to my knowledge. I guess the question would be why would you store 
the session id in a users url? I suppose
people who are to lazy to learn about cookies and don't mind having 
the ID logged on the server side.


Not to mention its *possible* that this id can be saved by a webspider 
and archived. If using cookies to store
these id's you won't have to worry about this problem. (unless there 
is a new super spider which logs cookies
that I am unaware of in production use?)

- zeno




Is there anything on CERT about the fact that URL encoded session IDs
get passed to referenced sites in the HTTP referer header?

Thanks,
Bob




                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                                                                           


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