SAC 025 | Fast Flux Hosting and DNS
[PDF, 166 KB]
"Fast flux hosting" refers to the automated, rapid modification of IP addresses assigned to hosts in the DNS to hide the location of web sites supporting malicious, illegal, or criminal activities. This SSAC Advisory explains how fast flux hosting exploits domain name and name registration services to frustrate detection and prolong the lifetime of illegal web sites. It examines current and possible methods of detecting and mitigating fast flux hosting at various points in the Internet by private network operators, ISPs, domain name registrars and TLD registries; for example, the identification and removal of malicious code installed on compromised computers and IP address isolation. In the process, the Advisory explains why fast flux hosting defies many such "traditional" mitigation techniques.
The Advisory also considers measures that certain registrars and registries implement today: monitoring changes to DNS records that are indicative of fast flux hosting, restricting DNS change frequencies and value ranges, and monitoring registrant account access to prevent automation. It further considers how registrars can use apply such measures to expedite illegal web site and domain name suspension processes. The Advisory recommends that ICANN, registries and registrars to consider these practices, establish best practices to mitigate fast flux hosting, and consider whether such practices should be addressed in future agreements.