Suspicious Fscan Internal Network Scanner Execution (via process_creation)

PremiumReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
HuntRule
Published
2026-09-05
Updated
2026-09-05

ATT&CK techniques

Discovery
  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Lateral Movement

  10. Collection

  11. C2

  12. Exfiltration

  13. Impact

What it detects

This rule detects execution of the fscan network scanner with host file and silent output options as observed in the MeshAgent and SuperShell intrusion. Fscan is used by the actor to enumerate internal hosts and open ports for lateral movement.

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Suspicious Nmap Scanner Probe URIs in HTTP Requests (via webserver)
Suspicious Internet Scanning for Docker and Kubelet Ports via masscan
Possible Network Service Scanning via Nmap or Masscan (via process_creation)
Malicious Anonymous Login - Domain Specified (via security)
Suspicious Network Scanning Tool Execution
Malicious RDP Discovery Performed on Multiple Hosts (via rdp)
Suspicious Fscan Internal Network Scanner Execution (via process_creation)
Pivot detection · T1046 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.