5 Common DNS Attack Types and How to Prevent Them 

Key takeaways from the article:

• Growing Threats: DNS attacks are increasing, leading to serious risks such as data theft and reputational damage.
• System Vulnerabilities: DNS’s inherent security weaknesses make it a prime target for various hacker exploits.
• Attack Types: Common DNS attacks include hijacking, cache poisoning, and DDoS attacks.
• Detection and Prevention: Monitor DNS traffic and logs to detect attacks; use DNSSEC, encryption, and updates for prevention.
• Protection Strategies: Implement strict DNS security measures like DNSSEC and DDoS mitigation services to safeguard systems.

Introduction

DNS attacks have grown quickly in recent years, both in how often and how serious they are. In 2024, a DNSFilter report showed phishing attacks went up by 106%, and a huge 1,250% increase in blocking newly created malicious websites within a day. 

Because these attacks are getting worse, businesses and individuals need to understand the risks of DNS attacks, like stealing data, losing money, and damaging reputations. 

In this article, you’ll learn what DNS attacks are, how they work, the most common types of attacks, and how to spot and prevent them. 

What is a DNS attack? 

A DNS attack happens when hackers exploit Domain Name System (DNS) weaknesses. DNS is like the internet’s phonebook, which translates website names into the numerical IP addresses that computers need to connect. While DNS is essential in how the internet works, it wasn’t built with strong security, which makes it easier for attackers to target. 

Hackers can use these weaknesses to cause a variety of problems: 

• They might change DNS records to redirect traffic to malicious sites. 

• Some attackers can overwhelm DNS servers with too many requests at once, which causes crashes and disrupt services. 

• Others might trick users into visiting fake websites where sensitive information like passwords or credit card numbers can be stolen. 

Because DNS is critical to almost every online activity, these attacks can lead to major issues, such as data theft, financial losses, and the disruption of websites and services. 

How does DNS work and where are the vulnerabilities? 

DNS is important because it helps you find websites on the internet. Instead of remembering complicated numbers for each website, like “192.168.1.1,” you remember names like example.com. When you type a website’s name into your browser, DNS helps your computer figure out the right number (IP address) that corresponds to that name so it can connect to the correct website. 

Basic DNS functionality 

The basic functionality of DNS is simple. When you type a website’s URL into your browser, your computer needs to find the corresponding IP address. To do this, your computer first asks a special service called a DNS resolver for the right address.

The resolver checks if it already knows the answer by looking at its saved information. If it has the address stored, it quickly sends it back to your computer.

If not, the resolver begins searching for the answer by asking other DNS servers until it finds the correct one. Once it locates the right IP address, it returns it to your computer. With the correct address in hand, your computer can then connect to the website you want to visit. 

Vulnerabilities in DNS 

Even though DNS is highly useful, it has some major weak points, such as: 

• Lack of encryption. DNS queries and responses are usually sent in plain text, which allows hackers to intercept and manipulate them easily. 

• Cache poisoning. Hackers can trick DNS servers into storing fake data. This means that when users try to visit a legitimate website, they could be redirected to a harmful one instead. 

• Manipulating responses. Since DNS servers talk to each other to resolve queries, attackers can slip in fake responses before the legitimate ones arrive, leading to users unknowingly visiting fraudulent websites or exposing sensitive data. 

These vulnerabilities make DNS an attractive target for cyberattacks, as manipulating it can result in widespread disruption or theft of valuable information. 

Common types of DNS attacks you should know 

DNS attacks come in various forms, exploiting different weaknesses in the Domain Name System. Below are some of the most common types of DNS attacks. 

DNS cache poisoning (DNS spoofing) 

DNS cache poisoning, also called DNS spoofing, is a type of cyberattack where hackers trick the DNS into sending people to fake or malicious websites. Instead of going to the real site they want, users end up on a harmful site that might steal their personal information or spread viruses.

Hackers do this by giving false information to the DNS, which then saves that incorrect information. This kind of attack can lead to the theft of important details, like passwords and credit card numbers. 

DNS tunneling 

DNS tunneling is a hacking trick where attackers secretly send information between computers using the DNS system, which usually helps match website names with their IP addresses and addresses. Hackers hide harmful data inside normal DNS requests.

This allows them to steal passwords or control infected computers from far away. DNS tunneling is dangerous because it can sneak past normal security checks, which makes it harder to notice. 

DNS hijacking 

DNS hijacking is a cyberattack where hackers manipulate the DNS settings. They change the address stored in the DNS, so when you try to visit a website, you’re actually taken to a different, potentially harmful, location. 

Hackers can do this by putting malware on a user’s device, controlling a router, or messing with DNS requests. Once this happens, people may be tricked into giving out personal information like passwords or credit card numbers on fake sites. DNS hijacking is often used to steal information or spread harmful software.  

DDoS attacks on DNS (DNS amplification and flood attacks) 

A DDoS (Distributed Denial of Service) attack on DNS targets DNS servers to disrupt their ability to resolve domain names. This makes your website unreachable, and two common types of these attacks are DNS amplification and DNS flood attacks: 

1. DNS amplification attack. The attacker sends small DNS queries with a spoofed IP address to DNS servers, which respond with much larger data packets to the victim’s IP. This overloads the victim’s network by saturating its bandwidth with excessive traffic. 

2. DNS flood attack. The attacker overwhelms a DNS server with a large volume of seemingly legitimate requests, consuming its resources like memory or CPU, which prevents it from responding to legitimate user queries. This attack often involves botnets and can also target DNS servers with invalid or nonexistent records, further straining the server’s capacity. 

NXDOMAIN attacks 

An NXDOMAIN attack is a kind of cyberattack that focuses on DNS servers. In this attack, hackers flood the servers with requests for websites that don’t exist. This makes the server waste time and resources and eventually stops working. Because of this, people can’t access real websites. These attacks are tricky to catch because they can seem like normal problems with the server. 

How to identify DNS attacks 

Identifying DNS attacks early can help prevent severe damage to your network and data. Knowing the symptoms and monitoring techniques is essential for detecting DNS attacks before they escalate. 

1. Identify symptoms of a DNS attack 

There are several signs that might suggest a DNS attack is happening: 

• Slow or unresponsive websites. If your websites are loading slowly or not at all, it doesn’t always mean a DNS attack. It could be due to other technical issues. But if you’ve already fixed those issues, a slow website could be caused by attacks like DNS amplification or DNS flood attacks. 

• Incorrect site redirections. If users are being sent to unintended or suspicious websites instead of the correct ones, this could be a sign of a DNS hijacking or cache poisoning attack. 

• Frequent errors in DNS resolution. If you notice a high number of NXDOMAIN responses (errors indicating a domain does not exist), this might indicate an NXDOMAIN attack, which overwhelms DNS servers with invalid requests. 

2. Monitor your DNS traffic regularly 

Regularly monitoring DNS traffic is important for detecting signs of an attack. Here are some key things to watch for: 

• Spikes in DNS queries.  If you suddenly see a big increase in the number of DNS requests, this could mean there’s a Distributed Denial of Service (DDoS) attack or a DNS flood attack happening. 

• Frequent request failures. If you notice an unusually high number of failed DNS queries, this might indicate that a DNS resolver or authoritative server is under attack. 

• Unusual patterns. Look for abnormal traffic patterns, such as large numbers of requests for non-existent domains or requests originating from unexpected sources. These can be signs of NXDOMAIN or DNS amplification attacks. 

3. Analyze DNS logs for suspicious activity 

Analyzing DNS logs can provide valuable insights into potential attack activity. Logs capture DNS queries, responses, and errors, which can help you pinpoint suspicious behavior. Here’s what to look for: 

• Anomalous requests. Requests that deviate from typical traffic patterns, such as large volumes of queries for subdomains or IPs not commonly accessed, may suggest malicious activity. 

• Frequent queries to unknown domains. Repeated requests to domains that are not recognized or rarely used by legitimate users may indicate a DNS tunneling or cache poisoning attack. 

• Changes in DNS records. Any unauthorized or unexpected changes in DNS records should be immediately investigated, as they may be a result of DNS hijacking. 

How to prevent DNS attacks 

1. Use DNSSEC (Domain Name System Security Extensions) 

DNSSEC helps keep your DNS data safe by making sure it comes from the right place. It adds a special code that proves a hacker hasn’t changed the data. This helps stop attacks that try to change DNS information and send users to dangerous sites. 

2. Apply access controls 

It’s important to control who can change your DNS settings. Using multi-factor authentication (MFA) makes sure only trusted people can access the DNS. MFA means you need more aside from your password, like a code sent to your phone, to log in.  

Tip: Use strong 2FA methods, such as authentication apps, rather than SMS, which is vulnerable to attacks like SIM swapping. This keeps attackers from getting in, even if they know your password. 

3. Use DNS Encryption 

DNS encryption is a way to protect DNS traffic from being seen or changed by attackers. Encrypt your DNS traffic to prevent attackers from viewing or altering it. Protocols like DNS over HTTPS (DoH), DNS over TLS (DoT), or DNSCrypt can encrypt (or scramble) the DNS information to make sure that only the right person can read it. 

4. Keep DNS servers up to date 

DNS servers need to stay updated so they can block new attacks. New software updates fix security problems that attackers might try to use. Therefore, keeping your DNS server software up to date helps block hackers from exploiting security weaknesses. 

5. Audit DNS zones 

Regularly check your DNS zones to ensure no outdated or unsafe DNS records are left behind. If you’re unfamiliar with DNS zones, they’re sections of the DNS system that store important information about your domain, like IP addresses, mail servers, and other key details. Cleaning up these records helps close security gaps that hackers could exploit, much like tidying your house to keep intruders out. 

6. Deploy a DNS firewall 

A DNS firewall is like a protective shield for your network. It checks all the DNS requests (which are like phone calls that help computers find websites) and blocks any bad ones before they can cause harm. This helps stop attacks, such as DNS tunneling, where hackers sneak bad data into normal requests, or DNS amplification, where too much traffic is sent to crash a system. 

Action steps: 

1. Set up a DNS firewall. Install a DNS firewall that works with your system. 

2. Keep it updated. Regularly update the firewall’s rules so it can block new types of bad traffic that hackers might use. 

7. Disable DNS recursion 

DNS recursion is when a DNS server helps resolve requests for domains it doesn’t control. For example, if your server doesn’t know a website’s IP address, it will ask other servers for the answer. While helpful for browsing, this can expose your server to attacks like DNS cache poisoning, where attackers give false answers to these queries and change DNS records. 

To protect your server, you can disable DNS recursion in the server’s configuration settings. If you’re using software like BIND or PowerDNS, look for the recursion settings in the configuration file (such as named.conf in BIND). Disabling DNS recursion reduces the risk of these attacks. 

8. Use a DDOS mitigation service 

DDoS (Distributed Denial of Service) attacks overwhelm your server with so much fake traffic that it can’t handle it, causing it to go offline. A DDoS mitigation service, like Cloudflare or Akamai, helps manage large traffic spikes and keeps your server running smoothly. 

These services act like a shield that blocks fake traffic and lets real visitors through. They monitor your server for unusual traffic patterns and quickly filter out the bad traffic, so your site stays online. 

To use a DDoS mitigation service, you can sign up on their websites, and they’ll guide you through the setup process. It’s an easy way to protect your server without having a deep security knowledge. 

Act now to secure your DNS and protect your business 

As DNS attacks keep growing, it’s not enough to just know about the risks—you need to act. Things like using DNSSEC, doing regular audits, and getting DDoS protection are necessary steps. 

But it doesn’t end there. Hackers are always finding new ways to attack, so you have to stay on top of it by learning and upgrading your security. Checking your defenses regularly will help make sure your DNS stays safe and strong.  

Are you ready to start securing your DNS and stay ahead of threats? Explore our comprehensive security solutions here to give your business the protection it deserves.  

Frequently Asked Questions (FAQs)