DNS security: Definition and best practices

What is DNS security?

Reliable DNS providers implement various security measures against DNS spoofing, hijacking, and DDoS attacks, including protocols like DNS over HTTPS (DoH) for enhanced privacy. Security tools like domain name system security extensions (DNSSEC) protect against cyberattacks by assigning unique signatures to data pieces, allowing verification of the data’s authenticity. DNS filtering helps filter out harmful websites and blocks malicious ones.

Although trustworthy DNS providers employ advanced security tools to manage DNS-associated risks, hackers sometimes slip through and may still harm your devices or networks. So, DNS servers also need careful monitoring and regular audits to mitigate traffic anomalies and identify threats.

Why DNS security is essential

DNS infrastructure was designed to simplify the interaction between humans and the internet and plays a fundamental role in the internet’s infrastructure. So, setting up a safe DNS security system is crucial for individuals and businesses to prevent cyberattacks.

DNS security practices help individuals maintain personal data and online safety. Meanwhile, it is a way for businesses to protect digital assets and prevent DNS spoofing and DDoS attacks, often causing data breaches and costly service outages.

Types of DNS attacks

Hackers employ different methods to exploit DNS server security and obtain confidential user information. DNS spoofing, tunneling, hijacking, amplification, and NXDOMAIN attacks are the most dangerous DNS attacks that criminals use to disrupt, divert, or manipulate DNS traffic.

DNS spoofing

DNS spoofing, or cache poisoning, is when an attacker corrupts the DNS cache to redirect unsuspecting users to fraudulent websites that mimic the user’s intended destination. DNS spoofing infects users' computers with malware, monitoring their internet activity and stealing sensitive information. This method of a DNS attack is extremely dangerous. The corrupted DNS data can sit in a user’s device for a significant amount of time without being noticed and lead them to malicious websites.

DNS tunneling

Hackers use DNS tunneling to circumvent network limitations by entering false data into DNS queries and responses, allowing them to reroute DNS requests to their servers. In the event of a successful attack, attackers take control of the apps on the device and access sensitive user information.

DNS hijacking

DNS hijacking, DNS redirection, or DNS poisoning is when an attacker redirects DNS queries to malicious websites. Hackers intercept DNS traffic, take over routers, and alter DNS settings, or install malware on users’ computers.

DNS amplification attacks

A DNS amplification attack employs DDoS attack tactics to target DNS infrastructure. It disrupts network functionality by flooding it with small DNS queries, usually through a botnet. Then, DNS servers respond with much larger replies and direct the amplified traffic to the victim’s network, overwhelming it and causing service outages.

NXDOMAIN attacks

An NXDOMAIN attack, or DNS water torture attack, happens when an attacker overflows a DNS server with a series of requests for non-existent records. Such attacks deplete traffic resources, causing denial of service for legitimate requests and compromising normal website or service performance. Hackers usually use automated botnets to perform NXDOMAIN attacks.

What are the best DNS security practices?

Employing the following DNS security solutions may protect your personal or business data from prying eyes and prevent hackers from compromising your devices.

• Use domain name system security extensions (DNSSEC). DNSSEC secure DNS servers by assigning cryptographic signatures to DNS records. If the DNS request doesn’t match the associated signature and comes from a non-authoritative server, DNSSEC will reject it to protect your network from DNS spoofing and cache poisoning.
• Run regular DNS audits. Thorough DNS server monitoring involves routinely checking DNS settings to identify unusual system behavior or security loopholes that cybercriminals could exploit. DNS audits can also help you identify outdated records that can be erased, ensuring smooth DNS system performance.
• Use secure DNS providers. Choose a trustworthy and security-oriented DNS provider that supports DNSSEC and has built-in tools against DDoS attacks. A secure DNS defends traffic against eavesdropping, tampering, and data trackers.
• Implement access control lists (ACLs). ACLs help organizations restrict unauthorized users from accessing confidential business information and reduce the potential attack surface.
• Enable rate limiting. Rate limiting helps mitigate the risk of DDoS attacks. It restricts requests from a single IP address that surpasses a certain query threshold, making it more difficult for attackers to flood the system.

What are DNS security extensions (DNSSEC)?

DNS security extensions (DNSSEC) are a set of protocols that authenticate DNS records by assigning digital signatures to DNS data. Initially, DNS servers don’t employ an authentication process, so DNSSEC adds a security layer to DNS traffic.

Find a more detailed explanation of DNSSEC, including use cases, benefits, and instructions on enabling it below.

DNSSEC use cases

DNSSEC prevent hackers from redirecting users to malicious domains through DNS spoofing or cache poisoning. These protocols may also help reduce spam and phishing attacks by securing email servers and verifying the authenticity of email messages, which is especially vital for businesses. Another crucial element for commerce is secure online transactions, which DNSSEC help establish and assure customers that their requests are reaching the authentic site.

DNSSEC may also enhance the security of your Internet of Things (IoT) devices by preventing man-in-the-middle (MITM) attacks. They mitigate the risk of DNS-based cyberattacks on critical infrastructure, preventing significant electricity or water supply disruptions. So while hackers develop new DNS-related hacking techniques every day, the role of DNSSEC become increasingly vital to diminish DNS vulnerabilities.

Benefits of DNS security extensions

DNSSEC provide a variety of benefits that enhance the security and reliability of DNS infrastructure for individuals and business environments:

• Data accuracy. DNSSEC establish smooth transit of DNS data, allowing users to trust that they are reaching the correct website and not being redirected to a malicious site.
• Verification. DNSSEC help ensure users receive correct and unaltered information from a website by digitally signing DNS data.
• Reliability. Businesses implementing DNSSEC into their domains demonstrate a responsible approach to internet security, increasing consumer trust in their services.

What does DNSSEC protect against?

DNSSEC protect you against a variety of cyber threats and DNS-related vulnerabilities. It’s important to mention that DNSSEC don’t encrypt DNS traffic in the way that DNS-over-HTTPS (DoH) or DNS-over-TLS (DoT) protocols do. They add a layer of authentication and integrity to DNS data and form a comprehensive DNS security strategy.

Some of the cyber threats that DNSSEC are constructed to protect your devices and networks against include:

• DNS spoofing and cache poisoning.
• Man-in-the-middle attacks.
• Unauthorized data modification.
• Phishing and redirect attacks.
• Subdomain hijacking.

How to enable DNSSEC

Usually, DNSSEC configuration varies depending on your DNS provider and the host site interface. However, not all DNS providers support DNSSEC, so ensure your provider does. If it does support DNSSEC, the service provider will probably have dedicated support articles or guides on its website to walk you through the process of enabling DNSSEC on your domain.

What is a DNS firewall?

A DNS firewall is a tool that may prevent you from landing on malicious websites that could harm your device or network. Businesses also use firewalls to restrict their employees from accessing specific sites.

System administrators set rules for DNS firewall traffic filtering, allowing the blocking of malicious domains that violate these rules. A DNS firewall is regularly updated with the latest security threats, significantly enhancing DNS security and safeguarding from malware and phishing attacks.

Next-generation DNS firewalls (NGFWs) employ an even more advanced approach against DNS-related security threats, including features like application-level inspection and intrusion prevention. They control applications on a granular level, preventing application-layer attacks through DNS.

How NordVPN helps with DNS security

Besides offering a safe and encrypted online experience, NordVPN provides advanced DNS security features for your DNS traffic protection. NordVPN comes with a private DNS feature that shields your online activity, encrypts DNS queries, and offers unwanted traffic filtering.

In addition to the handy private DNS, NordVPN also features DNS leak protection, which prevents your DNS requests from being accidentally exposed to cyber threats due to bad or faulty configuration.

Because DNS is often referred to as the phone book of the internet, these NordVPN features may be the cornerstone to protecting your DNS traffic from hackers attempting to gain access to your data through phishing, man-in-the-middle attacks, and DNS hijacking.