What is DNS Rebinding Attack?

What is DNS Rebinding Attack? And How it Works And Protection?

DNS rebinding is a form of computer attack or can say domain name computer based attack. In this attack, a malicious web page causes visitors to run a client-side script that attacks machines elsewhere on the network.

A DNS rebinding attack uses JavaScript in a malicious Web page to gain control of a router.

DNS rebinding attack can be used to breach a private network by causing the victim’s web browser to access machines at private IP addresses and return the results to the attacker. It can also be employed to use the victim machine for spamming, distributed denial-of-service attacks or other malicious activities.

Cybercriminal can also do DNS rebinding attack through Malicious advertising and then they can access private information on the network.

How DNS Rebinding works?

The attacker registers a domain (such as anydomain.com) and delegates it to a DNS server under the attacker’s control. The server is configured to respond with a very short time to live (TTL) record, preventing the response from being cached. When the victim browses to the malicious domain, the attacker’s DNS server first responds with the IP address of a server hosting the malicious client-side code.

Also See: What is Malware? and How To Protect Against it?

For instance, they could point the victim’s browser to a website that contains malicious JavaScript or Flash scripts that are intended to execute on the victim’s computer.

The malicious client-side code makes additional accesses to the original domain name (such as attacker.com). These are permitted by the same-origin policy. However, when the victim’s browser runs the script it makes a new DNS request for the domain, and the attacker replies with a new IP address. For instance, they could reply with an internal IP address or the IP address of a target somewhere else on the Internet.

How can we Protect Themselves?

The following techniques attempt to prevent DNS rebinding attacks:

1. Always use a strong password for your router.
2. To Disable admin access console to your router from any external network.
3. Web browsers can implement DNS pinning: the IP address is locked to the value received in the first DNS response.
4. This technique may block some legitimate uses of Dynamic DNS, and may not work against all attacks. However, it is important to fail safe (stop rendering) if the IP address does change, because using an IP address past the TTL expiration can open the opposite vulnerability when the IP address has legitimately changed and the expired IP address may now be controlled by an attacker.
5. Private IP addresses can be filtered out of DNS responses.
6. External public DNS servers with this filtering e.g. OpenDNS.
7. Local sysadmins can configure the organization’s local nameservers to block the resolution of external names into internal IP addresses. This has the downside of allowing an attacker to map the internal address ranges in use.
8. DNS filtering in a firewall or daemon e.g. dnswall.
9. Web servers can reject HTTP requests with an unrecognized Host header.
10. The Firefox NoScript extension provides partial protection (for private networks)
11. It was first discovered in 1996 and affected Java Virtual Machine.