Secure Your Enterprise with Robust DNS: A Guide to NIST SP 800-81r3

DNS translates human-readable domain names through DNS requests into machine-readable IP addresses, enabling seamless access to online resources. However, this core functionality makes it a prime target for cyberattacks. Compromised DNS security can lead to:

• Data breaches: Attackers can redirect users to fake websites to steal credentials or sensitive information.

• Malware infections: DNS can be used to distribute malware by resolving malicious domain names.

• Distributed denial-of-service (DDoS) attacks: DNS servers can be overwhelmed with traffic, including amplification attacks, that can disrupt services.

• Circumvention of Zero Trust architectures: Open resolution of DNS queries can be a route to bypass Zero Trust network controls.

NIST SP 800-81r3 emphasizes that a well-secured DNS infrastructure is essential for cyber resiliency, defense-in-depth strategies, and Zero Trust architectures.

The deployment guide provides in-depth coverage of various aspects of DNS security. Some of the key points include:

• Using protective DNS: Using protective DNS to block malicious DNS queries, filter content, and comply with regulatory requirements; protective DNS also provides valuable data for digital forensics and incident response
  

• Protecting the DNS protocol: Implementing measures to ensure the integrity of DNS services, such as using encrypted DNS (DNS over TLS [DoT] and DNS over HTTPS [DoH]) and DNSSEC
  

• Securing DNS infrastructure: Deploying dedicated DNS servers and ensuring high availability and resiliency
  

• Managing threats to authoritative services: Implementing measures to prevent zone transfer threats, zone content threats, dynamic update threats, and DNS NOTIFY misuse
  

• Securing recursive/forwarding services: Implementing encrypted DNS, restricting the use of public DNS providers, detecting data exfiltration through DNS tunneling, and enabling DNSSEC validation
  

• Securing stub resolvers: Protecting individual devices by securing their DNS resolvers

This NIST DNS security deployment guide provides essential strategies for IT professionals and cybersecurity teams to protect their network infrastructure from evolving DNS attacks and cyberthreats. Enterprises should review and implement:

• Protective DNS and advanced threat prevention
• DNS protocol security and encrypted communication 
• DNS infrastructure security
• Authoritative DNS protection
• Recursive DNS security
• Stub resolver security
• Information leakage prevention
• External domain integrity and advanced threat mitigation

Using protective DNS services, such as a DNS firewall with real-time threat intelligence, provides comprehensive network security by blocking malicious DNS queries, filtering unwanted content, and ensuring regulatory compliance.

These services provide valuable forensic data for incident response while integrating with existing security architectures like security information and event management (SIEM) systems and security operations centers (SOCs).

Protecting the DNS protocol requires implementing encrypted DNS technologies, including DoH, DoT, and DNSSEC validation to ensure communication integrity and prevent DNS hijacking, DNS spoofing attacks, and machine-in-the-middle exploits.

Securing DNS infrastructure involves deploying dedicated DNS servers with anycast implementation, automated failover mechanisms, and geographic distribution to ensure high availability and to mitigate DDoS attacks, including DNS amplification attacks.

Managing threats to authoritative services includes implementing access control lists for zone transfers, transaction signature (TSIG) authentication, dynamic update security with Generic Security Service Algorithm for Secret Key Transaction (GSS-TSIG) validation, and DNS NOTIFY protection to prevent zone-based attacks and unauthorized modifications.

Securing recursive/forwarding services involves encrypted DNS implementation, public DNS provider use restriction, DNS tunneling detection for data exfiltration prevention, and DNSSEC validation to protect internal clients while maintaining network performance.

Securing stub resolvers provides device-level DNS security through local resolver configuration, DNS cache poisoning prevention, and enterprise endpoint management using group policies and mobile device management integration for comprehensive DNS security across all devices.

Reducing the amount of information exposed in DNS records to limit potential reconnaissance by attackers minimizes information leakage. This includes sanitizing DNS responses, implementing split-horizon DNS configurations, carefully managing public-facing DNS record content, and protecting IP address information from unauthorized disclosure.

Preventing sophisticated attacks — including dangling CNAME exploitation, lame delegation exploitation, and look-alike domain exploitation — through proactive domain monitoring, certificate management, and DNS hygiene practices addresses external authoritative domain integrity.

Securing your DNS infrastructure is paramount in today’s threat landscape. NIST SP 800-81r3 provides a comprehensive guide to help enterprises strengthen their DNS security posture. 

By implementing the recommendations outlined in this guide, organizations can significantly reduce their risk of DNS-related attacks and improve their overall security resilience.