Once the victim clicks on a specially crafted Facebook URL they can be redirected to a malicious website.
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:
The following Google query can be used to find vulnerable URLs:
site:facebook.com inurl:"track.php?" inurl:"r="
Potentially allow an attacker to compromise a victim’s Facebook account and/or computer system.
4. Affected Products:
6. Time Table:
2/27/2011 Reported Vulnerability to the Vendor
2/28/2011 Vendor Acknowledge Vulnerability
6/25/2011 Verified the Vulnerability is Fixed
Discovered by Nathan Power