CISA, in collaboration with the National Security Agency, Federal Bureau of Investigation, Australian Signals Directorate, Canadian Centre for Cyber Security, and the National Cyber Security Centre of New Zealand, issued a joint advisory on the growing cybersecurity threat of “Fast Flux.” This malicious technique allows cybercriminals and nation-state actors to evade detection by rapidly changing Domain Name System (DNS) records, such as IP addresses, linked to a single domain. By constantly altering these records, fast flux creates a dynamic, resilient infrastructure that conceals malicious activities and makes it harder for defenders to track or block the attackers’ operations. The technique is used to support command-and-control (C2) communications, enabling attackers to maintain persistent, undetected connections with compromised systems.
The advisory highlights that many organizations and service providers have gaps in their defenses against this technique, which poses a significant threat to national security. To mitigate this risk, the advisory encourages service providers, particularly Protective DNS (PDNS) providers, to develop more effective fast flux detection and blocking capabilities. It also stresses the importance of a multi-layered defense strategy, combining DNS analysis, network monitoring, and threat intelligence, to better identify and respond to fast flux activities. The agencies urge government bodies, service providers, and cybersecurity professionals to work together to close these defense gaps and improve overall cybersecurity resilience against this evolving threat. For more detailed information, please refer to the advisory issued by CISA and its partners.