DNS spoofing: Everything you need to know

What is DNS spoofing?

DNS spoofing is a cyberattack used to redirect internet users to fake or malicious websites. Attackers compromise existing DNS records and manipulate IP addresses to send users to fake websites they’ve made. These websites look legitimate on the surface, but they can steal your data, install malware, or conduct other harmful actions behind the scenes. 

Some attackers also use the DNS fast flux technique, which involves constantly changing the IP addresses linked to malicious domains using a network of compromised devices. This technique makes the fake sites harder to detect or shut down. 

DNS spoofing attacks are very difficult to spot in real time. As you’re surfing the internet, you don’t usually see what your browser is doing behind the scenes. You likely won’t notice a site’s illegitimate DNS record on your own, which is why it’s so important to have good cybersecurity measures in place. 

What is DNS?

The DNS (domain name system) is a system that translates domain names into IP addresses to help web browsers find the right site. When you enter a domain name into your web browser, the DNS finds the corresponding IP address for that website. This request is processed through a network of DNS servers and takes just seconds to complete. Computers can’t process alphabetical URLs on their own because they need the numerical IP address to process web traffic and send it to the right place. 

How does DNS spoofing work?

DNS spoofing works by finding vulnerable DNS records or protocols and exploiting them to redirect web traffic. 

DNS queries flow through a network of servers to find the right IP address. The request starts at a DNS recursor server, then flows through root, TLD, and authoritative nameservers. If a hacker gets direct access to any of these servers, they can modify existing records or change incoming requests to send unsuspecting internet users to their malicious websites. 

Rather than accessing the servers directly, some hackers conduct a man-in-the-middle (MITM) attack instead. To do this, they intercept a DNS request before it reaches the server network. Then, they change the request to send the victim to a fake website. 

DNS spoofing can also exploit the protocols in the DNS system. For example, hackers can use the address resolution protocol, or ARP, to edit DNS records and change the flow of web traffic. In rare cases, hackers break into the data centers where DNS servers are located, and physically compromise those servers to launch DNS spoofing attacks. However, this situation is rare because modern data centers have extensive security measures.

These strategies work because the DNS system was built in the 1980s and was not designed with modern cybersecurity risks in mind. The DNS focuses primarily on fulfilling web traffic requests quickly and doesn’t have many safeguards to prevent external manipulation. 

Examples of DNS spoofing 

DNS spoofing attacks follow a specific process. Hackers use this technique to spread false IP addresses through several steps:

1. 1.The hacker creates a fake website with their local IP address. The website looks like a legitimate online banking platform, but it’s designed to collect victims’ credit card details. 
2. 2.The hacker uses a man-in-the-middle attack to intercept traffic between the DNS recursor and the banking platform’s DNS records. To do this, they use a tool like dsniff’s arpspoof or Bettercap. 
3. 3.The hacker uses the spoofing tool to send their fake IP address back to the victim’s device. This step redirects them to the fake website instead of the real one. 
4. 4.The fake IP address remains in the DNS cache for the banking platform for several hours. During that time, several other users are redirected to the fake website. 

DNS spoofing vs. DNS cache poisoning

The terms “DNS spoofing” and “DNS cache poisoning” are often used interchangeably, but there is a slight difference in their meanings. DNS spoofing refers to any attack that manipulates the DNS system to alter web traffic.

DNS cache poisoning is a specific type of DNS spoofing where a hacker injects fake DNS data into the DNS resolver’s cache, or memory. When an internet user makes a request, the DNS resolver will send back the fake data, directing the user to a malicious website. 

The cache helps the DNS process requests quickly by storing frequently-used IP addresses. This way, DNS requests don’t have to go through the entire server network every time. Instead, the DNS resolver can pull the information it needs from the cache. However, this part of the DNS system is easiest for hackers to exploit. 

Potential consequences of DNS spoofing

DNS spoofing can be incredibly dangerous, compromising the victim’s privacy and security. Here’s what can happen if you encounter a spoofed website. 

Malware downloads

Spoofed websites often contain automatic malware downloads. If you’re redirected to these sites, you could end up with dangerous ransomware, spyware, worms, or viruses on your device. 

Malware can damage your computer and compromise your privacy in a number of ways. For example, ransomware locks your files and demands an exorbitant amount of money to return them. Spyware tracks your online activity, exposing passwords, financial data, and other personal information to hackers. Viruses and worms can damage your files and even crash your device, making it almost impossible to use. 

Phishing attacks

Many DNS spoofers redirect their victims to phishing websites, which they use to collect usernames, passwords, addresses, credit card numbers, and other financial information. 

Phishing websites are designed to look like legitimate, trustworthy websites, tricking visitors into sharing personal data. For example, a hacker might create a website that looks like a login page for your bank, or for popular online platforms like Google and Amazon. When you enter your login information, it goes straight to the hacker. 

Identity theft

In severe cases, DNS spoofing can lead to identity theft. After stealing your personal data with phishing sites or malware, hackers often sell that information on the black market. From there, cybercriminals use it to access your bank account and steal your identity. 

Compromised security updates

Some cybercriminals will use DNS spoofing to prevent you from updating your software programs or downloading cybersecurity tools. 

Say you need to update your web browser due to a recently-detected vulnerability. DNS spoofers will create a website that looks like the official update page and contains a fake update file. 

Since you never actually updated your web browser, the hackers can exploit that vulnerability to steal your data. They can also use fake update files to spread malware. 

Censorship

Some governments use DNS spoofing to censor online content. The most notable example of this is China’s Great Firewall, which uses DNS spoofing to redirect traffic to approved websites. Other countries that have used DNS spoofing for censorship include North Korea and Russia. 

DNS spoofing attack methods

Attackers use different tactics to spoof DNS addresses and redirect internet users to their fake websites. They may create copies of real websites, fill them with malware, or simply show a message that the real one was “hacked.”

DNS spoofing is also used to conduct DDoS attacks. The hacker uses DNS spoofing to redirect web traffic from several other domains to the IP address of the website they’re targeting. The site can’t handle the huge influx of requests and crashes, giving hackers the opportunity to steal data or launch more invasive attacks behind the scenes. 

Let’s take a look at the tactics hackers use for DNS spoofing. 

Compromising DNS server

This method is the most obvious way to spoof a DNS record, but it’s also the most difficult for hackers to execute. Attackers need to obtain credentials from a user with access to the DNS server they want to target. 

To get these credentials, hackers might use various phishing techniques or keylogging malware. Once they have them, they can log in and change the records in the DNS server, sending unsuspecting users to malicious IP addresses. 

This strategy is more complicated than a cache poisoning attack, but it has a longer-lasting effect. The fake IP address stays in the server until someone notices and changes it back. This IP address also spreads to other DNS servers when they send traffic requests, and will stay in their caches as needed. 

Cache poisoning

Cache poisoning is the most popular DNS spoofing tactic. It’s easier for hackers than breaking into a server, but the results don’t last as long. This strategy allows the fake IP address to spread to other DNS servers’ caches, exposing more people to dangerous websites. 

Here’s how it works: The attacker sends a query to the DNS server network. The DNS resolver sends the query to the nameserver. Instead of passing it onto the authoritative DNS server as usual, the attacker responds to the nameserver themselves, posing as the authoritative DNS server and sending back a fake IP address. 

Since the DNS resolver doesn’t have a verification process, that fake IP address ends up in the DNS servers’ cache. Once the faulty record is there, it’s sent out to other DNS servers that have requested it. The cache expires every few hours, but that’s plenty of time for the fake DNS entry to spread, especially if it’s spoofing a popular web domain. 

Performing a man-in-the-middle attack

If you’re using a public Wi-Fi network or other unsafe internet connection, you might be vulnerable to a man-in-the-middle attack. Hackers often use these attacks as a DNS spoofing strategy. 

To do this, the hacker intercepts your connection, so they can see everything you do online and use that information against you. Whenever your browser sends a request to a DNS server, the attacker intercepts it and responds with a fake IP address to send you to a malicious website. 

These websites often look exactly like popular online stores, social media networks, or banking sites. They’re designed to trick you into revealing your login credentials, credit card information, and other sensitive data. If you don’t know how to spot a fake website, you might not even notice that something is off and unknowingly reveal your personal information.

Exploiting the time-to-live (TTL) settings

Another popular strategy for hackers is exploiting the time-to-live (TTL) settings in the DNS cache. The DNS TTL tells the server how long to store a cached IP address before requesting a new one. TTLs can range anywhere from a few minutes to a full day, depending on the site’s needs. 

When conducting a DNS spoofing attack, hackers will break into the DNS servers and change the TTL settings so a fake IP address will stay in the cache for longer. This tactic exposes more people to the malicious website. 

How to prevent DNS spoofing attacks

When you’re browsing the internet, you can’t do much to prevent a DNS spoofing attack, but you can learn how to spot fake websites and avoid sharing sensitive data with them. Before interacting with the site, check the URL to make sure it’s correct, and look for typos or odd design choices that wouldn’t be present on a legitimate website. You should also check to make sure the site has a TLS/SSL certificate, as indicated by the padlock icon next to the URL. 

If you run a website, it’s your responsibility to implement security measures and prevent DNS spoofing attacks. This practice ensures that visitors can browse your site safely. Here are steps you can take to prevent your web domain from getting spoofed. 

Implement domain name system security extensions (DNSSEC)

DNSSEC is a protocol that verifies the authenticity of DNS records by adding unique cryptographic signatures that hackers can’t replicate. When someone requests your site’s IP address, the DNSSEC protocol receives corresponding cryptographic data, which confirms that the site is legitimate. Most modern web hosts support DNSSEC, and you can enable it directly through your provider’s DNS management console. 

Implement IPsec (Internet Protocol Security)

IPsec is another protocol that helps protect your site’s IP address from MITM attacks and DNS spoofing. IPsec encrypts IP addresses in transit, so cybercriminals can’t intercept them on public networks. This protocol is most often used to set up VPNs and encrypt web traffic. 

Use trustworthy DNS servers

When choosing a hosting provider for your website, make sure they use secure, trustworthy DNS servers. Review their privacy and cybersecurity policies to see what measures they’re taking to prevent DNS spoofing and other cyber attacks. You’ll also want to read reviews from previous customers to get an idea of their reputation. 

Encrypt your DNS requests 

Use protocols like DNSCrypt to encrypt DNS requests as they move between the DNS server system and the end client. Encryption uses cryptography to scramble data when it’s in transit, making it virtually impossible for cybercriminals to decode. When DNS traffic is encrypted, hackers can’t launch MITM attacks. 

Update your systems regularly

Cybercriminals are constantly looking for vulnerabilities in modern technology. They exploit these vulnerabilities to launch cyberattacks, including DNS spoofing. 

Updating both your software and hardware regularly is the best way to eliminate these vulnerabilities. Software providers release updates and patches regularly to address new vulnerabilities, and it’s important to install them right away. A patch manager tool can help you track new updates so you don’t miss them. 

Use network security tools

Network security tools help both website administrators and internet users stay safe from hackers. Tools like intrusion detection and prevention systems, firewalls, and antivirus tools can all prevent DNS spoofing attacks from exposing your personal information. 

NordVPN’s Threat Protection Pro™  can help keep you safe from DNS spoofing because it notifies you when you’re visiting a suspicious website so you can avoid unwanted malware downloads.  NordVPN also has a private DNS function that shields your DNS requests from third parties.