The National Security Agency released a cybersecurity product, “Adopting Encrypted DNS in Enterprise Environments,” Thursday explaining the benefits and risks of adopting the encrypted domain name system (DNS) protocol, DNS over HTTPs (DoH), in enterprise environments. The release provides solutions for secure implementation based on enterprise network needs.
DNS translates domain names in URLs into IP addresses, making the internet easier to navigate. However, it has become a popular attack vector for malicious cyber actors. DNS shares its requests and responses in plaintext, which can be easily viewed by unauthorized third parties. Encrypted DNS is increasingly being used to prevent eavesdropping and manipulation of DNS traffic. As encrypted DNS becomes more popular, enterprise network owners and administrators should fully understand how to properly adopt it on their own systems. Even if not formally adopted by the enterprise, newer browsers and other software may try to use encrypted DNS anyway and bypass the enterprise’s traditional DNS-based defenses.
DoH encrypts DNS requests, preventing eavesdropping and manipulation of DNS traffic. While good for ensuring privacy in home networks, DoH can present risks to enterprise networks if it isn’t appropriately implemented. The recommendations detailed will assist enterprise network owners and administrators in balancing DNS privacy and governance for their networks. It outlines the importance of configuring enterprise networks appropriately to add benefits to, and not hinder, their DNS security controls. These enterprise DNS controls can prevent numerous threat techniques used by cyber threat actors for initial access, command and control, and exfiltration.
NSA recommends that an enterprise network’s DNS traffic, encrypted or not, be sent only to the designated enterprise DNS resolver. This ensures proper use of essential enterprise security controls, facilitates access to local network resources, and protects internal network information. All other DNS resolvers should be disabled and blocked.
NSA seeks to regularly release unique, actionable, and timely cybersecurity guidance to secure the Department of Defense, National Security Systems, and the Defense Industrial Base. For more information or other cybersecurity products, visit NSA.gov/cybersecurity-guidance.