What can be done to prevent Distributed Denial of Service (DDoS) attacks against the DNS infrastructure? What can individuals or organizations who operate DNS servers do to their own systems to help reduce the threat of DDoS attacks? ICANN’s Security and Stability Advisory Committee (SSAC) took on this issue recently and released a new report this week: “SAC065: SSAC Advisory on DDoS Attacks Leveraging DNS Infrastructure“. It is available as a free PDF download in English.

While the report is not about DNSSEC, per se, it is about the overall issue of “DNS security” and outlines steps that can be taken to reduce the potential of DNS-based DDoS attacks. This is critical if we are to get DNSSEC more widely deployed because there are some DNS server operators who have pushed back about DNSSEC citing concerns about the larger size of DNSSEC packets could help amplify DDoS attacks.

The recommendations for the industry include the following (with the report providing more detail on each):

Recommendation 2: All types of network operators should take immediate steps to prevent network address spoofing. Recommendation 3: Recursive DNS server operators should take immediate steps to secure open recursive DNS servers. Recommendation 4: Authoritative DNS server operators should investigate deploying authoritative response rate limiting. Recommendation 5: DNS operators should put in place operational processes to ensure that their DNS software is regularly updated and communicate with their software vendors to keep abreast of latest developments. Recommendation 6: Manufacturers and/or configurators of customer premise networking equipment, including home networking equipment, should take immediate steps to secure these devices and ensure that they are field upgradable when new software is available to fix security vulnerabilities, and aggressively replacing the installed base of non-upgradeable devices with upgradeable devices.

We agree with those recommendations and definitely encourage people to read the SSAC report and implement as many recommendations as possible.

Working together we can make the Internet more secure!