vBulletin Two-Step External Link Module 'externalredirect.php' Cross-Site Scripting Vulnerability

Bugtraq ID:	39597
Class:	Input Validation Error
CVE:
Remote:	Yes
Local:	No
Published:	Apr 20 2010 12:00AM
Updated:	Apr 20 2010 12:00AM
Credit:	Edgard Chammas
Vulnerable:	VBulletin Two-Step External Link 0
Not Vulnerable:

vBulletin Two-Step External Link Module 'externalredirect.php' Cross-Site Scripting Vulnerability

Two-Step External Link module for vBulletin is prone to a cross-site scripting vulnerability because the application fails to properly sanitize user-supplied input.

An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This may help the attacker steal cookie-based authentication credentials and launch other attacks.

vBulletin Two-Step External Link Module 'externalredirect.php' Cross-Site Scripting Vulnerability

An attacker can exploit this issue by tricking an unsuspecting user to follow a malicious URI:

The following example URI is available:

http://www.example.com/externalredirect.php?url=XSS

vBulletin Two-Step External Link Module 'externalredirect.php' Cross-Site Scripting Vulnerability

Solution:
Currently we are not aware of any vendor-supplied patches. If you feel we are in error or if you are aware of more recent information, please mail us at: [email protected].

vBulletin Two-Step External Link Module 'externalredirect.php' Cross-Site Scripting Vulnerability

References:

• vBulletin Homepage (vBulletin)
  
• Vbulletin - Two-Step External Link XSS ([email protected])