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What is a DNS Hijacking?

calendar icon August 18, 2020 | by Steve Ellis

A Domain Name System (DNS) is essential to all companies that depend on the internet to generate sales—it is a crucial element to the performance and legitimacy of an organization's web-based applications and cloud services. A loophole in your DNS could translate to the loss of users, access to user credentials by hackers, unavailable content, and user frustration, to mention a few. A DNS hijacking or User Redirection Attack is a common type of Domain server breach that targets a vulnerability in the stability of a network’s domain server system.

DNS attack, Domain Name Server hijack

It could be an attack on the DNS infrastructure itself, making it unavailable, or subverting the website’s users to go to an alternative destination. Either way, these attacks leverage the DNS as part of the attack strategy. When users visit the hijacked website, they are redirected to an illegitimate website that's disguised as the hijacked website.


How is the DNS Hijacked?

Cybercriminals understand that your website's domain name system is a unique, trusted protocol and that many companies don't care to monitor their domains for malevolent activities. For this reason, they may initiate a range of attacks on the organization's Domain Name System, and get away with it.

DNS translates human-friendly URLs into machine-friendly Internet Protocol (IP) addresses. It, therefore, provides internet users with a way to match search queries to relevant websites. Any device that’s connected to the internet has an IP address made up of numbers. The NDS serves a fundamental role of syncing up domain names with the appropriate IP addresses enabling website owners and users to choose memorable domain names while the devices, on the other hand, can use machine-friendly IP addresses.

For example, suppose you run a query by typing into your search engine. In that case, a request will be sent from your computer to the appropriate DNS resolver, which is a computer that searches IP addresses associated with your search query. The DNS resolver is programmed to communicate with high-level domain servers, find a match and send it back to your device.

To execute an attack, the perpetrators incorrectly resolve the DNS to send your users to malicious websites. They achieve this by taking over routers, hacking the Domain Name Server communication, or installing malware on website users’ devices. Once a company’s DNS is successfully hijacked and the users redirected to a fake website, it translates the authorized IP into the illegitimate IP address of the hijacker’s malicious DNS.  


Why Are DNSs Hijacked?

A DNS may be hacked for a range of reasons. The hijacker may use it for pharming, which is to display ads to users to generate revenue or phishing, which is directing users to a fake version of your website with the aim of stealing data or login information.

Internet Service Providers (ISP) are also known to use domain redirection to control users’ DNS queries to collect user data. Other organizations use domain hijacking for censorship or redirecting users to alternative websites. 


Types of DNS Hijacking Attacks

There are a number of ways in which a DNS hijacking attack can be executed. The four most common types of DNS hijacking attacks are:

List of DNS Attacks: local DNS hijack, Router DNS hijack, Rogue DNS Server, MIM DNS hijack

1. Router DNS Hijack

The DNS router is a hardware device that domain service providers use to match domain names to their corresponding IP addresses. Most routers come with preset passwords and a host of firmware vulnerabilities. Cybercriminals can take advantage of weak default passwords and the vulnerabilities to take over the router and reconfigure the DNS settings to their benefit. If they successfully overwrite the DNS router, they can easily divert the traffic to another website and jam your company’s website to make it inaccessible.


2. Man-In-The-Middle DNS Hijacking

This is also called DNS spoofing. In this case, the attacker targets and intercepts the communication between the website’s traffic and the site's DNS alters the DNS settings hence directing the traffic to a malicious IP address. 


3. Local DNS hijack

A local DNS attack installs malware on the website user's computer. The malware, usually a trojan malware disguised as legitimate software, gives the cyber thieves access to users' network systems, enabling them to steal data and change DNS settings to direct the users to malicious websites.


4. Rogue DNS Server

In this type of DNS hijacking, the cybercriminal intercepts the DNS server and alters the DNS settings to divert traffic to fake websites.


Preventing DNS Hijacking

There are numerous precautionary steps you can take to improve your DNS security to prevent DNS hijacking. We have three categories of the basic mitigation measures:

mitigation measures to avoid name server hijacking

1. Mitigation Measures to Prevent Name Server Hijacking

As outlined earlier in this post, cyber thieves target DNS routers and reconfigure them to redirect traffic to malicious locations on the internet. The DNS name server is a crucial resource that should have strong security measures to prevent attackers from hacking and launching attacks on website users.

Below are elaborate measures that the IT team can take to improve your site's name server's security. 

Install Firewalls Around Your DNS Resolver—Every DNS has resolvers, legitimates resolvers. Attackers may install fake resolvers in the DNS to compromise it and to intercept the legitimate resolvers. To prevent this from happening, have the IT team place the legitimate resolvers behind a firewall, and shut down all non-required DNS resolvers.

Increase Restrictions on Access to Name Servers—An attacker could be an enemy within your organization. As such, the IT team should ensure a physical security system, multi-factor authentication access, and a reliable firewall to limit access to the organization's DNS.

Prevent Cache Poisoning—common measures to prevent website cache poisoning include; randomizing user identity, randomizing server source ports, and using both upper and lower cases in your organization’s domain name.

Fix the Known vulnerabilities, immediately—cybercriminals capitalize on obvious vulnerabilities to initiate attacks on DNS. Have your IT team examine the DNS for any vulnerabilities and immediately patch them up to prevent attacks.

Avoid Zone Transfers—DNS zone records are delicate files that contain data that is often targeted by attackers. The hackers may pose as slave name servers requesting for a zone transfer, which involves copying server zone records. To prevent this vulnerability, avoid zone transfers.


2. Mitigation Measures for End-Users

Besides advertising products to hijacked traffic, DNS hijackers also target user data and credentials. Website users can prevent hijacking by frequently changing their passwords, installing and updating their computer anti-viruses, and using reliable virtual private networks.


3. Mitigation Measures for Website Owners

If your organization uses a Domain Name Registrar, your IT team can take the following steps to prevent DNS hijacking:

Ensure Secure Access—DNS access should be limited to only a few members of the IT team, who should have a multi-factor authentication whenever accessing the domain name server registrar. This measure will significantly avoid DNS hacking. If convenient for the IT team, only a few whitelisted Internet Protocol addresses should access the domain name registrar.

log in secure

Client Lock—To enhance DNS security, some DNS registrars use client locks. The lock disables the option to change DNS records unless the request is made from a particular IP address.

Use A Domain Name Service provider with DNSSEC—A DNSSEC uses digital signatures and public keys to verify the validity of DNS requests. If your DNS registrar offers DNSSEC, enable it to add a layer of protection that makes it challenging for attackers to intercept and redirect traffic from your website to a fake site.


Don’t Let Your DNS Be Compromised 

DNS hijacking is a reality that happens to vulnerable websites around the world. Despite considerable efforts to avert DNS spoofing and redirecting of traffic, attackers are always finding new cunning ways to access organizations' networks and users' devices, compromising data, and stealing credentials.

To keep your organization’s website safe from DNS hijacking, the IT team must always be on the lookout for vulnerabilities that attackers may take advantage of and patch them up. Conducting a cybersecurity assessment and following the measures we have outlined in this post, you will detect malicious activity on your website, and implement the appropriate steps to stop or prevent a DNS hijacking.


Start your journey to better security

Categories: Network Security, Security Breach, DNS Hijacking

Steve Ellis

About Steve Ellis

Snow hater, technology lover, information sharer, camper, biker, and hiker. Steve Ellis has been with Office1 since 1995. He’s filled many positions from a brand new copier tech to his current position serving as the VP of Professional Services. He has a passion for learning and sharing the knowledge that might make someone’s life easier. He holds several certifications including MCSA and MCITP. He is currently working on his CompTIA CySA+. Steve has been in the copier industry for more than 25 years and has been interested in tech since 2000.

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