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Re: Linksys WRT54 GL - Session riding (CSRF)

A malicious link executing unnoticed by the administrator may open the firewall.

The catch is that this exploit don't work unnoticed, because the admin get notification in the browser that there has occured an error with the cerificate ["Unable to verify the identity of Linksys as a trusted site"] and he has explicity allow it. In other words first he has to allow to be attacked...

Tomaz schrieb:
Ok, and what does it change...there are still the same vulnerabilities in
their equipment. Should we stop checking and publishing them just because
somebody informed the vendor 2 years ago?

-----Original Message-----
From: Florian Weimer [mailto:info@xxxxxxx] Sent: 11. januar 2008 11:54
To: tomaz.bratusa@xxxxxxxxxxxxxx
Cc: bugtraq@xxxxxxxxxxxxxxxxx
Subject: Re: Linksys WRT54 GL - Session riding (CSRF)

* tomaz bratusa:

Linksys WRT54GL is prone to an authentication-bypass
vulnerability. Reportedly, the device permits changes in its
configuration settings without requring authentication (CSRF).

This specific attack scenario has been publicly documented for a long
time (note the final paragraph):

| Isn't your exploit somewhat complicated?  Just put
| | <img
| | on a web page, and trick the victim to visit it while he or she is
| logged into the Cisco router at over HTTP.  This has been
| dubbed "Cross-Site Request Forgery" a couple of years ago, but the
| authors of RFC 2109 were already aware of it in 1997.  At that time,
| browser-side countermeasures were proposed (such as users examining
| the HTML source code *cough*), but current practice basically mandates
| that browsers transmit authentication information when following
| cross-site links.
| | Such attacks are probably more problematic on low-end NAT routers
| whose internal address defaults to and which generally
| offer HTTP access, which makes shotgun exploitation easier.  So much
| for the "put your Windows box behind a NAT router" advice you often
| read.


Cisco PSIRT had been approached about this issue a couple of months
before that BUGTRAQ posting, IIRC.

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