Neustar recently published research that detailed how Domain Name System Security Extensions (DNSSEC) can be subverted as an amplifier in Distributed-Denial-of-Service (DDoS) attacks.
In the research, “DNSSEC: How Savvy DDoS Attackers Are Using Our Defenses Against Us”, Neustar found that on average, DNSSEC reflection can transform an 80-byte query into a 2,313-byte response, an amplification factor of nearly 30 times, which can easily cause a network service outage during a DDoS attack, resulting in lost revenue and data breaches.
“DNSSEC emerged as a tool to combat DNS hijacking, but unfortunately, hackers have realized that the complexity of these signatures makes them ideal for overwhelming networks in a DDoS attack,” said Joe Loveless, Director Product Marketing, Security Services, Neustar. “If DNSSEC is not properly secured, it can be exploited, weaponized and ultimately used to create massive DDoS attacks.”
DNSSEC was designed to provide integrity and authentication to DNS, which it accomplishes with complex digital signatures and key exchanges. As a result, when a DNS record is transferred to DNSSEC, an extraordinary amount of additional information is created. Additionally, when issuing the DNS command, “ANY,” the amplified response from DNSSEC is exponentially larger than a normal DNS reply.
Key findings and recommendations from the research included:
- DNSSEC Vulnerabilities Are Prolific – Neustar examined one industry with 1,349 domains and determined 1,084 of them (80 percent) could be maliciously repurposed as a DDoS attack amplifier (they were signed with DNSSEC and responded to the “ANY” command).
- The Average DNSSEC Amplification Factor is 28.9 – Neustar tested DNSSEC vulnerabilities with an 80-byte query, which returned an average response of 2,313-bytes. The largest amplification response was 17,377-bytes, 217 times greater than the 80-byte query.
- The Anatomy of a DNSSEC Reflection Attack – Neustar illustrates the command and control servers required to run the botnets and scripts that target DNS nameservers to execute DNSSEC amplification attacks.
- Best Practices for Mitigation –For organizations that rely on DNSSEC, Neustar recommends ensuring that your DNS provider does not respond to “ANY” queries or has a mechanism in place to identify and prevent misuse.
“Neustar is focused on using connected sciences to connect people, places and things, which is why network security is so imperative,” said Loveless. “As more organizations adopt DNSSEC, it is critically important to understand how to secure it. The time to fix it is now.”
For more information about “DNSSEC: How Savvy DDoS Attackers Are Using Our Defenses Against Us” see: