What is DNS Hijacking?

What Exactly is DNS?

Domain Name System (DNS) functions as an Internet phone book. It works by converting your favorite URL – your favorite news site or blog – into a computer-friendly language. The most significant purpose of a DNS is to link internet users to websites by converting human-friendly domain names into machine-friendly IP addresses.

  • A DNS resolver, also known as a recursive DNS server, is the first stage in this process which deals with the first request and eventually converts the domain into an IP address.

  • The DNS resolver determines the matching IP addresses that computers can read by looking for DNS records on one or more authoritative DNS name servers.

  • The authoritative DNS name server is undeniably important in the lookup process. This is because it informs the recursive DNS server about the location of certain websites.

  • Internet Corporation for Assigned Names and Numbers (ICANN) accredits domain name registrars. Users may register and lease domain names with it. Long strings of numbers – IP addresses – identifying these domains would be difficult for consumers to remember if they didn't have domain names.

In a nutshell, domain names make surfing easier for everyone.

What is DNS Hijacking?

DNS queries are largely unencrypted, which is an issue and an opportunity for malicious actors to intercept requests. We've already discussed DNS and privacy concerns, but now let's look at how and why DNS hijacking occurs.

  • DNS hijacking is a type of DNS attack in which attackers attempt to divert your traffic to a malicious domain by wrongly resolving your DNS requests.

  • A phoney server established up by the attackers would transmit a bogus IP address belonging to their malicious website to your device while your browser is resolving a URL, intending to deceive you into utilizing the unauthorized version of the website you wish to access. These are often websites where users enter their sensitive data, allowing attackers to steal their data.

Cache Poisoning

Hackers use cache poisoning and other tactics to hijack a user's DNS. When a hacker accesses a website's cache, this is known as Website Cache Poisoning.

  • Cache poisoning on a website is a complicated approach. It allows malicious items to be inserted into a website's cache, providing a false response – an infected page – to the user.

  • In DNS cache poisoning, the hacker inserts bogus DNS records into the memory of the DNS resolver. Essentially, criminals poison the DNS cache with a false IP address with the same domain name as a real website without modifying DNS settings. The DNS server then resolves the IP address and directs the user to the fraudulent site.

  • If a user submits login credentials into a false online bank login form, for example, the hacker might take over the user's account and steal money. Financial organizations, in particular, might be a prime target for DNS hijacking attacks. Users may be unaware that they visit a phoney website since they trust their banking services.

How Can You Prevent DNS Hijacking?

DNS is a protocol that has been around for a long time. It was founded in 1983, long before any of today's cyber security issues. It was unsurprising that it lacked necessary security features (such as authentication). No one would have guessed at the time that the DNS might be exploited for nefarious purposes.

In addition to the fundamental lack of security, enterprises may not be properly monitoring DNS traffic. How can you defend yourself from DNS spoofing?

We can all take a few simple actions to better defend ourselves from DNS hijacking or any other sort of DNS attack −

  • Avoid clicking on any strange websites or links, whether in your emails or on social media.

  • Examine the URL to ensure that it belongs to a reputable website.

  • Avoid using public Wi-Fi networks since they are nearly usually unencrypted, allowing anybody to observe your DNS activity if they so desire.

We've looked at various strategies that you can use to defend yourself from domain hijacking, and many of them are also applicable to DNS hijacking.

Types of DNS Hijacking

Let us now find out the ways in which DNS Hijacking can take place −

Man-in-the-middle Attack

  • An attacker intercepts the connection between the user and the website or application the user wishes to visit during a man-inthe- middle attack.

  • The attacker then redirects the user's DNS requests to a rogue DNS server, which the attacker controls.

  • Finally, the attacker presents a variety of target IP addresses in order to direct the victim to potentially harmful websites. DNS spoofing is another name for this sort of DNS hijacking attack.

  • Spoofed websites are imitated versions of well-known websites that can deceive users into giving financial or other sensitive information. The culprits may eventually be able to gather vast quantities of personal data, sell it, or use it for other harmful reasons.

Rogue DNS Server

  • DNS servers may be hacked, and DNS records changed by cybercriminals to divert DNS searches to counterfeit websites operated by hackers.

  • When hackers tamper with the DNS settings on the router, they get control of the user's DNS system. The DNS router – a device often used by domain service providers – may then be modified to utilise a rogue DNS server and divert traffic at any moment.

  • Perpetrators can hijack DNS requests and redirect all online traffic to malicious domains. As a result, these sites can infect devices with malware and assist in the theft of important information.

DNS Manipulation by ISP

DNS hijacking, interestingly, supports more than just fraudulent activity.

  • DNS queries can potentially be manipulated by ISPs. Why? They can manipulate users' DNS requests in order to collect internet usage data or display advertisements.

  • When a user tries to input a domain name that does not exist, an NXDOMAIN response message is usually displayed. The DNS resolver or DNS lookup that converts a domain name to an IP address cannot resolve the request in this scenario. ISPs can load a redirect page to offer adverts or collect data when they hijack this NXDOMAIN answer.

  • Furthermore, government entities may utilise DNS redirection techniques for censorship, such as redirecting people away from unlawful or obscene information.

Malware on Router

  • Another DNS hijacking approach is used by hackers to not only redirect DNS requests but also to infect machines with malware and do more damage (e.g., steal and sell data).

  • When malware is installed on a user's computer or router, a local DNS hijack occurs (router DNS hijack).

  • The virus gains network access, allowing hackers to change local DNS settings and attack all users on the same network.

  • Unfortunately, due to firmware flaws and weak default passwords, routers are frequently targeted by hackers.

Updated on: 14-Apr-2022


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