D-Link DSL-2640B ADSL Router - Authentication Bypass

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# Exploit Title : D-Link DSL-2640B (ADSL Router) Authentication Bypass
# Date          : 22-02-2012
# Author        : Ivano Binetti (http://ivanobinetti.com)
# Vendor site   : http://www.d-link.com
# Version       : DSL-2640B 
# Tested on     : Firmware Version: EU_4.00; Hardware Version: B2
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+-------------------------[Authentication Bypass by Ivano Binetti]--------------------------------------------------------------------------+
Summary

1)Introduction
2)Vulnerability Description
3)Exploit

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1)Introduction
D-Link DSL-2640B is an ADSL Router using (also) a web management interface. 

2)Vulnerability Description
This router allows an attacker to bypass authentication and to login with administrator ("admin") credentials.
In fact when the administrator is logged in and an internal attacker will connect to web management interface (default is http://192.168.1.1:80) 
he will be able to see the MAC Address of logged admin. Symply changing his MAC Address the attacker can bypass authentication and login as 
administrator.

3)Exploit
For example in OSX Snow Leopard you can on the fly change your MAC Address with the simple following CLI command:

ifconfig en0 ether <admin_mac_address>   (where en0 is the name of your network interface)