Hack an Ethernet ADSL Router

Here is a detailed information on how to exploit the vulnerability of an ADSL router.

Step-1: Go to www.whatismyipaddress.com. Once the page is loaded you will find your IP address. Note it down.
Download angry IP scanner

Step-2: Open Angry IP Scanner, here you will see an option called IP Range: where you need to enter the range of IP address to scan for.
Suppose your IP is 117.192.195.101, you can set the range something as 117.192.194.0 to 117.192.200.255 so that there exists atleast 200-300 IP addresses in the range.
Step-3: Go to Tools->Preferences and select the Ports tab. Under Port selection enter 80 (we need to scan for port 80). Now switch to the Display tab, select the option “Hosts with open ports only” and click on OK.I have used Angry IP Scanner v3.0 beta-4. If you are using a different version, you need to Go to Options instead of Tools
step-4: Now click on Start. After a few minutes, the IP scanner will show a list of IPs with Port 80 open

Step-5: Now copy any of the IP from the list, paste it in your browser’s address bar and hit enter. A window will popup asking for username and password. Since most users do not change the passwords, it should most likely work with the default username and password. For most routers the default username-password pair will be admin-admin or admin-password.

Just enter the username-password as specified above and hit enter. If you are lucky you should gain access to the router settings page where you can modify any of the router settings. The settings page can vary from router to router. A sample router settings
If you do not succeed to gain access, select another IP from the list and repeat the step-5. Atleast 1 out of 5 IPs will have a default password and hence you will surely be able to gain access.
What can an Attacker do by Gaining Access to the Router Settings?

By gaining access to the router settings, it is possible for an attacker to modify any of the router settings which results in the malfunction of the router. As a result the target user’s computer will be disconnected from the Internet. In the worst case the attacker can copy the ISP login details from the router to steal the Internet connection or play any kind of prank with the router settings. So the victim has to reconfigure the router in order to bring it back to action.

The Verdict:

If you are using an ADSL router to connect to the Internet, it is highly recommended that you immediately change your password to prevent any such attacks in the future. Who knows, you may be the next victim of such an attack.

Since the configuration varies from router to router, you need to contact your ISP for details on how to change the password for your model.