Матрица MITRE ATT&CK

Technique on mitre.org

T1568.001: Fast Flux DNS

Adversaries may use Fast Flux DNS to hide a command and control channel behind an array of rapidly changing IP addresses linked to a single domain resolution. This technique uses a fully qualified domain name, with multiple IP addresses assigned to it which are swapped with high frequency, using a combination of round robin IP addressing and short Time-To-Live (TTL) for a DNS resource record.

The simplest, "single-flux" method, involves registering and de-registering an addresses as part of the DNS A (address) record list for a single DNS name. These registrations have a five-minute average lifespan, resulting in a constant shuffle of IP address resolution.

In contrast, the "double-flux" method registers and de-registers an address as part of the DNS Name Server record list for the DNS zone, providing additional resilience for the connection. With double-flux additional hosts can act as a proxy to the C2 host, further insulating the true source of the C2 channel.

Detection

ID	DS0029	Data source and component	Network Traffic: Network Traffic Flow	Description	In general, detecting usage of fast flux DNS is difficult due to web traffic load balancing that services client requests quickly. In single flux cases only IP addresses change for static domain names. In double flux cases, nothing is static. Defenders such as domain registrars and service providers are likely in the best position for detection.

ID	DS0029	Data source and component	Network Traffic: Network Connection Creation	Description	Monitor for newly constructed network connections that may use Fast Flux DNS to hide a command and control channel behind an array of rapidly changing IP addresses linked to a single domain resolution.

ID	Data source and component	Description
DS0029	Network Traffic: Network Traffic Flow	In general, detecting usage of fast flux DNS is difficult due to web traffic load balancing that services client requests quickly. In single flux cases only IP addresses change for static domain names. In double flux cases, nothing is static. Defenders such as domain registrars and service providers are likely in the best position for detection.
DS0029	Network Traffic: Network Connection Creation	Monitor for newly constructed network connections that may use Fast Flux DNS to hide a command and control channel behind an array of rapidly changing IP addresses linked to a single domain resolution.