Possible FIN7 DGA Command and Control Behavior

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This rule detects a known command and control pattern in network events. The FIN7 threat group is known to use this command and control technique, while maintaining persistence in their target’s network.

Rule type: query

Rule indices:

  • packetbeat-*

Severity: high

Risk score: 73

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Network
  • Threat Detection
  • Command and Control

Version: 1

Added (Elastic Stack release): 7.10.0

Rule authors: Elastic

Rule license: Elastic License

Potential false positives

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This rule could identify benign domains that are formatted similarly to FIN7’s command and control algorithm. Alerts should be investigated by an analyst to assess the validity of the individual observations.

Investigation guide

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In the event this rule identifies benign domains in your environment, the destination.domain field in the rule can be modified to include those domains. Example: ...AND NOT destination.domain:(zoom.us OR benign.domain1 OR benign.domain2).

Rule query

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event.category:(network OR network_traffic) AND type:(tls OR http) AND
network.transport:tcp AND
destination.domain:/[a-zA-Z]{4,5}\.(pw|us|club|info|site|top)/ AND NOT
destination.domain:zoom.us

Threat mapping

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Framework: MITRE ATT&CKTM