Same-Site Scripting: The Lesser-Known Vulnerability

February 9, 2016 | Views: 10554

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Hi Readers,

It’s quite possible that a sub-domain has a “loop back” address, i.e. Many security researchers and developers may not be aware of this lesser-known vulnerability.

Imagine a scenario where a user has to access “”. If the sub domain is configured with address and, if the user is already running a service on their localhost (Eg. Xamp/Wamp server running), he/she will obviously be redirected to the localhost services. He/she will never be able to visit “” unless the user has stopped the services on the localhost.


Run a Simple Test

Simply send a ping request to the sub domain to find the IP address:


Reply from bytes=32 time<1ms TTL=128


Many organization have the DNS misconfigured with the address (but, we won’t disclose all those websites). We will share that the famous Bug Bounty Program, HackerOne, had this issue. They were notified by a security researcher and fixed the vulnerability.


Let’s Fix the Issue

1. Change the IP address from to a random address.

2. Simply remove the sub-domain entry if it’s not needed.



Vinoth kumar

Security Researcher

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  1. thank you for sharing

  2. Great write up. I agree that this is the best description I have found yet. I was using dnsmap to scan some sites and came a cross this vulnerability. I had never heard of it mentioned anywhere else. (Promptly sending emails out to close these holes).

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