CISA Warns: Old DNS Trick 'Fast Flux' Is Still Thriving

The report summarizes a CISA advisory warning that threat actors—including ransomware groups, phishing criminals, and state-sponsored APTs—are abusing the decades-old fast flux DNS technique (and double flux variants) to rotate IPs/name servers rapidly and resist takedowns; it explains how fast flux works, the operational challenges defenders face, and includes expert pushback arguing the method is dated, relatively rare, and mitigated by modern protective DNS and domain-level detection.