A Deep Dive Into DNS Hijacking

TL;DR- A guide on DNS hijacking, showcasing what it is, how to hack vulnerable sites, and how to prevent these kinds of attacks.

Introduction

Domain Name System (DNS) hijacking is a process utilized by hackers to alter the resolution of a DNS, which redirects users to a different (and often malicious) website.

DNS-based attacks have become increasingly popular over the years, as many organizations do not track their DNS traffic for unusual or malignant activities. Cybercriminals have picked up on this, and leveraged the loophole to attack vulnerable websites.

How does DNS work?

Domain name systems essentially translate human-readable domain names (like thegrayarea.tech) into numerical IP addresses (like 162.159.153.4) that computers use to communicate with each other.

It’s a fundamental part of how the internet works, and it plays a crucial role in cybersecurity by helping to prevent attacks such as phishing, malware distribution, and DDOS (distributed denial of service) attacks.

When a user types a domain name into their web browser, the computer first sends a request to a DNS server in order to resolve (or translate) the domain name into an IP address.

The DNS server then looks up the IP address in its database, and responds with the corresponding value. This process happens quickly and transparently, allowing users to easily access websites with words instead of letters.

Important terminology to know →

DNS resolvers are used to look up and resolve domain names into IP addresses.

The DNS root servers provide a starting point for the resolution process by directing requests to the appropriate top-level domain (TLD) servers.

Authoritative name servers store the actual DNS records for a domain, including the IP addresses for the domain’s web and email servers.

Together, these systems work to create a decentralized network that can handle billions of DNS requests every day.

Types of DNS Hijacking attacks:

Local DNS Hijack: This type of attack occurs when a cybercriminal installs Trojan malware on a user’s computer, allowing them to steal data and alter DNS settings to redirect the user to fake websites.

Router DNS Hijack: Hackers can use a vulnerable DNS router to override and reconfigure its settings, redirecting traffic to a malicious website and making the original website inaccessible.

Man-in-the-middle DNS Hijack: Also known as DNS spoofing, this attack involves a hacker operating within the communication between a user and a DNS server to redirect the user to a harmful website.

Rogue DNS Hijack: In this attack, the hacker hacks the DNS server, alters its records, and redirects DNS queries to malicious websites that they own.

Mitigating these attacks:

To prevent DNS hijacking and general DNS exploitation, website owners and users should implement security measures. Here are some important steps you should take:

Install firewalls around DNS resolvers →

This helps secure your DNS by blocking external access and shutting down any unknown resolvers that may be installed by attackers during a DNS hijacking attack.

Implement heavy restrictions on domain name server access →

To reduce the risk of DNS hijacking, your IT team should utilize a physical security system and use multi-factor authentication for access to the name server. This helps prevent attackers within your organization from gaining access to your DNS.

Protect against cache poisoning →

Cache poisoning occurs when attackers insert malicious data into the cache of a DNS server. To prevent this, you can randomize user identities, make query IDs random, use random source ports for your server, and include both uppercase and lowercase characters in your website domain name.

Fix known domain bugs immediately →

Hackers often take advantage of vulnerabilities in domain systems to carry out DNS hijacking attacks. To prevent this, your IT team should regularly assess your DNS for bugs and fix them as soon as they’re found.

Keep resolvers and authoritative name servers separate →

When both are run on the same server, a DDoS attack on one can affect the other as well. To prevent this, run your resolvers and authoritative name servers on separate servers to protect against DNS hijacking.

Prevent zone transfers →

Hackers may try to access sensitive records in your DNS by disguising as slave name servers and requesting zone transfers. To prevent this, you can put measures in place to prevent these transfers, which will help protect your DNS from hijacking.

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