What is DNS Attack and How Does it Work?
July 23, 2019 Share

What is DNS Attack and How Does it Work?


DNS Attack is a type of cyber attack that exploits the weakness or vulnerability in Domain name system. Today, the internet has turned into an integral part of our life. From communicating to banking to shopping to traveling, every aspect of our life is around the internet.

Since the internet has been widely used, cybersecurity is a primary concern for most web users as every now and then we hear the news about cyber attacks.

Nowadays, a cyber attack is common. Even they are becoming a big headache for many IT companies and businesses. In recent years, some big names such as Google, The New York Times, etc. have fallen victim to cyber-attacks.

In today’s post, we will come to know about DNS Attacks, how they work and how to fight against them.

What is DNS Attack?

Indeed, DNS attacks happen when a hacker is able to find weaknesses to exploit in the DNS (Domain Name System).

Hackers take advantage of vulnerabilities to make DNS attack possible. In order to understand, how DNS attacks actually work, you will have to first understand how DNS works.

For those who don’t know, the domain name system is a protocol that interprets an alphabetic domain name into IP address. In short, its major function is to convert a user-friendly domain name into the computer-friendly IP address.

How DNS Works?

When a user types a domain name in the browser, a program available in the operating system known as ‘DNSresolver‘ searches for the IP address of that domain name.

First, DNS resolver searches its own local cache and check if it already has the IP address for that domain. If it does not find it in the local cache, It queries a DNS server to check if it knows the accurate IP address for that domain.

DNS servers work in a loop which means they are able to query each other to find the DNS server that knows the correct IP address of the domain name.

As soon as DNS resolver locates the IP address, it returns the IP address to requesting program. DNS caches domain address for future use as well.

Though Domain Name System is quite powerful yet it seems less focused toward the security. Maybe that’s why we are noticing different types of DNS attack.

To minimize the possibilities of DNS attacks, server administrators must take some necessary steps. They can use an upgraded version of DNS software and regularly configure servers to duplicate. At a personal level, users can flush their DNS cache to avoid security risks. If you don’t know how to flush DNS, read a resourceful post at hostinger.com.

How Hackers Use DNS?

The biggest issues with DNS system is that if on any account a hacker is able to find a way to replace the authorized IP address of a website with a rogue IP address, then any person trying to access that website will be sent to a bogus address. The user would not have any idea that he is accessing the wrong address.

One of the major problems with the DNS server configuration is that it does not remember its default configuration. Attackers take advantage of this loophole.

Types of DNS Attack

Over the past few years, a sudden increase has been noticed in DNS attacks. And this attack is not limited to small websites only.

Numerous popular websites such as Reddit, Spotify, Twitter have also complained about their inaccessibility to thousands of their users.

As DNS attacks are becoming all too common, we should learn to identify DNS attacks so that we can tackle the situation in a better. Let’s have a look at types of DNS attacks.

Zero-day attack- In this type of attack, the attacker exploits a formerly unknown vulnerability in the DNS server software or protocol stack.

Fast Flux DNS- Hackers swap DNS record in and out at high frequency to redirect DNS requests. This technique helps the attacker avoid detection as well.

DNS-Spoofing- DNS spoofing is also known as DNS cache poisoning. It is a type of computer security hacking. Attackers or hackers corrupt the whole DNS server by replacing the authorized IP address with the bogus IP address in the server’s cache. This way they redirect the whole traffic to a malevolent website and collect the crucial information.

This is one of the most popular phishing techniques attacker use to steal the information. Because users type the correct domain address in their browsers, they never realize that are accessing a fake or rogue website.

Therefore, it becomes challenging to detect this attack. Sometimes, users are not able to find it until the time to live (TTL) expires. TTL or time to live in the time till DNS resolver remember the DNS query before it gets expired.

The best method to prevent DNS cache poisoning attack should be time to time clearing of DNS cache.

DDoS Attack on DNS

The DDoS attack is referred to as Distributed Denial-of-service attack. It usually arises when multiple systems flood the resources of a targeted system. Attackers can use this attack against different types of systems which include DNS server as well.

A DDoS attack can crash the whole DNS server and make users unable to access the web. However, they will be able to access websites they have accessed recently if they are saved in the local cache.

DNS server attack can be a huge network security issue. Therefore, it should not be taken lightly by businesses. They should implement state-of-the-art safeguards to reduce and prevent the effects of such attacks.

How you can defend this attack depends on the role of your systems in the environment. However, you may take the following steps.

Get regular insight into what is actually going on in a network. You can take the help of technologies like IPFIX, NetFlow, etc. for the same.

DDoS attacks usually enter into the network that has excessive packet per second rates. Think of some good solutions for it.

Final Words

DNS attacks can be lethal to your security. Therefore, you must take every possible step to prevent them.

Have you ever been a victim of DNS attack? How did you prevent them? Do share your experiences with us.

This post What is DNS Attack and How Does it Work? originally appeared on GB Hackers.

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