Unusual Network Destination Domain Name

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A machine learning job detected an unusual network destination domain name. This can be due to initial access, persistence, command-and-control, or exfiltration activity. For example, when a user clicks on a link in a phishing email or opens a malicious document, a request may be sent to download and run a payload from an uncommon web server name. When malware is already running, it may send requests to an uncommon DNS domain the malware uses for command-and-control communication.

Rule type: machine_learning

Machine learning job: packetbeat_rare_server_domain

Machine learning anomaly threshold: 50

Severity: low

Risk score: 21

Runs every: 15 minutes

Searches indices from: now-45m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Network
  • Threat Detection
  • ML

Version: 3 (version history)

Added (Elastic Stack release): 7.7.0

Last modified (Elastic Stack release): 7.10.0

Rule authors: Elastic

Rule license: Elastic License

Potential false positives

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Web activity that occurs rarely in small quantities can trigger this alert. Possible examples are browsing technical support or vendor URLs that are used very sparsely. A user who visits a new and unique web destination may trigger this alert when the activity is sparse. Web applications that generate URLs unique to a transaction may trigger this when they are used sparsely. Web domains can be excluded in cases such as these.

Rule version history

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Version 3 (7.10.0 release)
  • Formatting only
Version 2 (7.9.0 release)
  • Formatting only