DNS Security Tools: Protect Your Network from DNS Attacks

DNS Security Tools: Protect Your Network from DNS Attacks. Domain Name System (DNS) is an internet protocol that provides an hierarchical system for naming domains. DNS acts as the internet’s phonebook that allows users to access websites using familiar names instead of having to remember IP addresses. 

DNS servers are vulnerable to a wide variety of threats. A popular threat is DNS spoofing or cache poisoning. In this case, an attacker redirects queries to a malicious domain by providing false information. This leads to users sharing sensitive data unknowingly. Another popular DNS risk of Distributed Denial of Service (DDoS) attacks against DNS servers, which renders websites inaccessible.

This article discusses various DNS security tools and techniques to protect your network from DNS based attacks. But before then, it’s imperative to understand how DNS works, especially the lookup process and why it’s important to secure it. Read on!

How DNS Works and Its Security Implications

Whenever you type a URL on your browser i.e www.cloudinfrastructureservices.co.uk and click enter, you initiate a series of actions. First, the browser (client) sends a request to a DNS server, which then locates the website’s IP address. The browser then searches the server where the website is hosted, then returns a response with the requested content. If the request web page cannot be found, it returns a 404 error.

The entire process of a browser looking for an IP address is known as a DNS lookup. While the DNS lookup process is crucial to the internet functionality, it comes with vulnerabilities. Hackers exploit some aspects to compromise the DNS. 

Here are some of the top DNS security threats:

DNS Spoofing/Cache Poisoning: here a hacker provides false DNS responses. They redirect users to malicious sites rather than the actual sites they wanted to visit. 

DNS Amplification Attack: hackers send a small query with a spoofed IP address to an open DNS resolver. The attacker targets a larger response to the victim. Since the response outweighs the query, this magnifies the amount of traffic the victim receives, potentially leading to a DDoS.

Domain Hijacking:  Attackers gain access to the control panel of the domain owner. After, they change the DNS settings and redirect traffic to an illegitimate website.

Man-in-the-Middle Attack: An attacker hijacks communications between a client and a DNS server, then provide the client with false DNS responses.

To avert these security threats, it’s imperative to adopt various security strategies and DNS security tools to secure your DNS server. Here are some of the best tools to use to secure your DNS:

Up next with DNS Security Tools: Protect Your Network from DNS Attacks is to read more about tools we apply for our DNS servers.

DNS Security Tools and Techniques

1. DNS Security Extensions (DNSSEC)

DNSSEC a suite of extensions to DNS, which provides origin authentication of DNS data, data integrity, and authenticated denial of existence. Uses cryptographic signatures to verify the authenticity and integrity of the DNS data. In simple terms, when a DNS resolver receives a DNS response, DNSSEC allows the resolver to verify that the response hasn’t been tampered with during transit.

DNSSEC uses digital signatures based on public key cryptography to authenticate the DNS data itself. This means that when the recursive resolver receives data, it verifies its legitimacy through the digital signature provided by the data’s owner. Ideally, DNSSEC effectively safeguards users from potential cyber threats arising from the DNS’s original design vulnerabilities.

2. DNS Firewall

A DNS firewall is like a digital gatekeeper that filters out potentially harmful web traffic from accessing the DNS server. It consistently analyzes DNS traffic and compares each user request against a continuously updated database of threat intelligence. For each request to  access a website, the firewall checks this request against a set of rules to determine its legitimacy. If the firewall detects malicious traffic based on this data, it denies it access. This ensures malicious traffic does not access the DNS server, improving legitimate users’ digital safety. 

A firewall provides a line of defence against cyber threats such as DDoS. Advanced DNS firewalls employ Artificial Intelligence (AI) tools to proactively detect even the most advanced security threats. Some of the top DNS firewalls include:

  • OpenDNS
  • SafeDNS
  • DNSFilter
  • Webroot
  • Cloudflare
  • Nexusguard
  • ScoutDNS
  • Infoblox

With these tools, you configure rules to filter traffic into your server and prevent malicious access. 

3. Domain Name System Security Gateway

A secure web gateway is a network security service that sits between users and the internet. It inspects web requests and blocks malicious websites and web requests. By integrating directly with domain name resolution processes, DNS Security Gateway serves as a protective layer. 

This approach not only simplifies web security but also offers a more streamlined experience for users. A secure web gateway includes security mechanisms such as HTTPS inspections, data loss prevention, and URL filtering to provide strong web security.

4. Intrusion Detection Systems (IDS)

IDSs enhance DNS security by monitoring network traffic and detecting potential malicious activity or policy violations. IDS tools employ anomaly and signature based detection. These two primary threat detection methods analyse network packets for known attack patterns. Given that DNS has standard request and response formats, any deviations or suspicious patterns in DNS traffic are identified using this approach. 

5. Intrusion Prevention Systems (IPSs)

IPSs are network security tools that continuously monitor and scrutinize individual network packets for potential malicious intent. Unlike Intrusion Detection Systems which are more passive, an IPS proactively prevents threats. If the system recognizes any harmful content, such as malicious DNS requests or responses indicating cache poisoning, domain hijacking, or other DNS-based attacks, it blocks those packets. By doing so, it prevents them from accessing the network. 

In addition to detection, an IPS seals security gaps in real time. It configures secondary firewalls to anticipate similar attacks in the future, and reinforce the network’s defences. These prevention systems are capable of detecting a ton of cyber threats, including DoS and DDoS attacks targeting DNS servers.

Techniques for Protecting Your DNS Network from DNS-Based Attacks

Now that you understand the various tools to use for DNS protection, what about the best practices to secure your DNS server. Below are several ways to protect your DNS Network from attack. These include:

1. Passive DNS Replication

Passive DNS provides a historical overview of DNS queries and responses which is quite different from the traditional DNS system. Passive DNS functions stores these DNS records, IP lookups, and associated statistics within a database.

Well, passive DNS works by replicating DNS traffic, and there are multiple methods to facilitate this replication. Deploy a passive sensor to monitor and record DNS traffic or integrate it as a module with a network monitoring service. It’s also possible to use it as a plugin for a name server or to extract data from stored network captures. The data collected provides historical perspective on DNS responses, illustrating the prior destinations of specific domains.

Passive DNS replication focuses solely on DNS traffic without associating it with specific client IP addresses. This ensures detection of malicious users while protecting legitimate users.

2. DNS Filtering

DNS filtering is a security approach whereby admins filter the sites available to users. It operates through the DNS lookup mechanism, determining which web content is accessible to users on its network. 

There are two primary methods of filtering:

  • by domain name
  • by IP address

Both methods are similar in nature, as the end result is the same. Domain name filtering prevents domains from undergoing the DNS lookup process. Similarly, filtering by IP address allows for the resolution of the IP address and domain name but denies user access to the resultant domain. The end user experience is identical for both methods. When users try to access a blocked domain, they are redirected to a DNS filter-hosted page. This page clarifies that the requested web page is blocked due to safety or appropriateness concerns.

DNS filtering offers protection against malicious web pages that launches malicious downloads and propagate threats like ransomware, malware, and viruses within networks. It neutralizes these threats at their origin, barring malicious web pages from loading. This technique proactively identifies and blocks these malicious domains, safeguarding users from accessing them.

3. DNS Response Rate Limiting (RRL)

DNS Response Rate Limiting (RRL) is a security approach implemented in DNS servers to prevent specific DDoS threats, especially DNS amplification attacks. In a DNS amplification attack, malicious attackers send multiple queries with fake source IP to open DNS resolvers. These resolvers, manipulated by the malicious queries, direct a large volume of responses to the victim’s address. Since the responses outweigh the original queries, this rapidly overwhelms the victim’s resources.

RRL works by monitoring and identifying patterns that suggest potential amplification attacks. If a DNS server observes an unusually high rate of responses going to a particular destination in a short time, it begins to limit the rate of those responses. In essence, RRL minimizes the impact on legitimate traffic, ensuring that genuine users aren’t denied service.

4. DNS Traffic Encryption

Normally, standard DNS traffic is sent in plain text. This format makes it vulnerable to attacks and surveillance. DNS encryption ensures this traffic is unreadable, protecting users from malicious users. 

To protect against this vulnerability, DNS encryption transforms this plain text data into a format only decipherable by the DNS client and resolver. If attackers capture encrypted DNS data, they can’t interpret it, shielding users from potential threats.

There are two methods of DNS traffic encryption:

  • DNS over HTTPS
  • DNS over TLS

Here are the major differences between DNS over HTTPS and DNS over TLS:

DNS over HTTPS (DoH)

DNS over HTTPS (DoH) enhances online privacy by encrypting DNS traffic. DoH encrypts DNS queries using HTTPS, which makes it difficult for users to understand the websites a user is accessing. This encryption ensures more private web browsing. In addition, it provides protection against attacks like DNS spoofing. With DoH, DNS responses are encrypted and authenticated, making it difficult for attackers to manipulate DNS data. This ensures users only visit the genuine versions of websites. 

DNS over TLS (DoT)

DNS over TLS (DoT) wraps DNS queries and responses within a layer of TLS encryption to secure them against unauthorized access. By utilizing the TLS protocol, DoT ensures that only the intended recipient can read the DNS query or response. This encryption makes it substantially harder for malicious users to find any usable information from intercepted responses, preserving user privacy.

Furthermore, DoT offers authentication mechanisms. This means that the communications are not only encrypted, but also the DNS client verify the identity of the DNS server. This authentication ensures that users communicate with a legitimate server and not a malicious one.

5. Deploy Anycast DNS

Anycast DNS is a networking approach where multiple servers share the same IP address. Instead of mapping one IP address to a single server location, Anycast allows the same IP address to be used by multiple servers across different geographical locations. When a user’s device sends a query to an Anycast IP address, the network directs that query to the nearest server, determined by factors like the fewest network hops or the lowest latency.

This Anycast DNS architecture provides resilience against DDoS attacks. With Anycast DNS, malicious traffic is spread out across multiple servers, which effectively dilutes the impact of such attacks. In nutshell, it becomes much harder for attackers to overwhelm a single target.

6. Lock the DNS Cache

Locking the DNS cache is a security approach that ensures data validity and integrity of the data held within the cache. The DNS cache contains recent lookups. By locking this cache, you prevent unauthorized modifications or poisoning of the cache.

Furthermore, locking the DNS cache prevents cache snooping. Snooping is the practice of querying a DNS server to determine if a particular domain has been recently accessed. If the DNS server responds well, it could reveal user activity. By locking the cache, you maintain user privacy and reduce potential intelligence gathering by malicious actors.

7. Avoid Single Points of Failure

In a DNS, a single point of failure is basically any one component that brings down the entire DNS service if compromised. This is dangerous because if a company’s DNS service goes down, it makes the company’s entire online presence.

To avoid single points of failure, you implement a redundant DNS infrastructure. This involves deploying multiple DNS servers, ideally in diverse locations. In case one server goes down, the other servers continue to respond to queries. 

8. Configure Access Control Lists (ACLs)

Access Control Lists (ACLs) refer to a set of rules that determine DNS servers access and actions they can perform. Basically, ACLs rules dictates which IP addresses accesses to the DNS service. Properly configured ACLs help safeguard the DNS server from unauthorized access or potential misuse.

9. Deploy Dedicated DNS Appliances

DNS appliances are specialized hardware devices designed specifically to handle DNS functions. They have built in security features to protect against various DNS specific vulnerabilities. With dedicated appliances, your organization optimize DNS performance, security, and overall server reliability.

10. Update the DNS Server Regularly

Regularly updating your DNS server ensures that it has the latest security patches. Updating patch vulnerabilities, ensures that your DNS server remains robust against emerging threats. You aid performance improvements, ensuring your DNS operations remain efficient and  it remains robust from security vulnerabilities.

Thank you for reading DNS Security Tools: Protect Your Network from DNS Attacks. We shall conclude this article title.

DNS Security Tools: Protect Your Network from DNS Attacks Conclusion

DNS security is about securing your server from malicious attacks and securing communications from client to server. Since DNS servers are highly targeted by various security threats, it’s imperative to implement various tools and techniques to counter these threats. DNS security tools such as DNSSEC, IDSs, and IPSs help detect and remediate security threats. Combined with the above DNS security best practices, you can easily create a secure DNS network and safeguard your systems.

Avatar for Dennis Muvaa
Dennis Muvaa

Dennis is an expert content writer and SEO strategist in cloud technologies such as AWS, Azure, and GCP. He's also experienced in cybersecurity, big data, and AI.

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