What is DNS Cache Poisoning & How to Prevent It?

DNS cache poisoning or DNS spoofing is better explained as driving organic traffic from a legitimate server to a fake one. It is a type of cyber attack that exploits the vulnerabilities of a domain. Many authoritative sites face a tremendous bounce rate and the ranking decreases.

The domain name system cache poisoning is a serious threat as it keeps spreading over DNS servers.

For example, DNS server of a crypto giant MyEtherWallet was hacked, and all the traffics redirected from the legitimate site to a suspicious one in April 2018.

As a result, the hackers deceived lots of users and stole almost around a hundred and sixty thousand dollars!

However, you don’t need to get panicked since all DNS issues like this are not a result of a DNS cache poisoning because we have got your back. Get all the details of DNS cache poisoning here along with the tricks to stay safe from it. Let’s have a look.

What is DNS?

DNS or the Domain Name System is kind of an internet phonebook. When you search for some information online through a domain name like abcd.com, the browser interact via IP address.

And the work of DNS is to convert a human-readable domain name to a numerical IP address that your PC reads.

How does DNS Caching Work?

There are multiple servers available on the internet. Because every internet service provider runs their own DNS servers, and DNS cache differs from each other.

In other words, your router collects cache information from the DNS servers of your ISP. Your PC saves some local DNS cache so that you get the prompt result when you search for the same thing again.

What is DNS Cache Poisoning?

DNS Cache Poisoning is a type of cyber attack in which the attacker uses an altered DNS record and redirect online traffic to a false web address.

How Does DNS Spoofing Works?

A potential attacker can imitate DNS nameservers to poison DNS Caches. The attacker requests the DNS resolver and then produce the reply when the DNS resolver queries the nameserver.

Since there is no verification for the DNS information, the attacker uses the User Datagram Protocol(UDP) instead of the Transmission Control Protocol(TCP).

The diagram below will make you understand the process:

TCP verifies the identity of the devices. Not only that but also both parties need to join hands to communicate using TCP. But in the case of the UDP, there is no guarantee that a certain connection is open.

That is why UDP is always vulnerable. An attacker can easily send a message via UDP and just pretend that it is a response from the official server by forging the header data.

Though there is some vulnerability in the DNS caching process still proceeding with the DNS spoofing is not an easy task to execute.

The reason behind this is the DNS server queries the legitimate nameserver indeed, alongside, the attackers do not get more than a few milliseconds to provide with the fake reply before the new reply from the original server comes. There is guesswork which the attackers must have to execute to a website.

People Also Search for: Best DNS propagation tools online

How to Prevent DNS Cache Poisoning?

DNS- the unencrypted protocol quickly catch traffics with spoofing. Moreover, the DNS server has specific criteria like not validating the redirected traffic receiving IP addresses.

You can secure your domain with DNSSEC protocol, the domain name server security. This protocol gives some extra protection to your domain with the additional verification processes.

DNS stores your records and a unique cryptographic signature. Your DNS resolvers then use this signature for authentication of a DNS response. This process makes sure that there is no tampering with your record.

Though DNS spoofing gets bashed by the DNSSEC, still it has some drawbacks.

Data Confidentiality Issue

DNS responses don’t get encoded by the DNSSEC. So still the hackers can track the traffic and do another type of attack.

Deployment Complexity

So many times DNSSEC gets misconfigured, so it forces a server to lose security. Additionally, your server may deny access to any website.

Zone Enumeration

Additional resource records are mandatory for signature validation. And individual records can easily verify the non-existence of a DNS zone. Furthermore, all existing DNS records can be collected just by drooling over DNS zones- this is called zone enumeration.

Final Thoughts

In spite of the drawbacks, DNSSEC is the only option to keep your server secure. Give it a try and stay safe from DNS cache poisoning and from the issues like dns server not responding.

We have shared all the necessary information above. Go through again and again for a better understanding of the whole concept.

If you face any issue in between then, you must get in touch with us. In case you have further query drop it in the comment box below. We will quickly revert. And don’t forget to share your opinion.

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