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Fast Flux DNS

A technique used by cybercriminals to rapidly change IP addresses to evade detection.

Understanding Fast Flux DNS


Fast Flux is used by botnets, phishing campaigns, and malware distribution networks to make their infrastructure resilient against takedowns. By dynamically rotating IP addresses linked to malicious domains, attackers ensure their servers remain operational despite efforts to block them.

Types of Fast Flux


  1. Single Flux – Frequently changes A records (IP addresses) mapped to a domain.

  2. Double Flux – Rotates both A records and NS (Name Server) records for greater persistence.

Best Practices for Detecting and Preventing Fast Flux DNS


1. Monitor Unusual DNS Behavior

  • Security tools like Threat Intelligence Platforms and SIEM systems can detect suspicious domain resolution patterns.

2. Use Blacklists and Threat Feeds

  • Block known Fast Flux domains using security intelligence sources.

3. Implement DNS Sinkholing

  • Redirects malicious domain queries to a controlled environment for monitoring.

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