Possible Ngrok RDP Tunnel Exposure via TCP 3389

PremiumReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
HuntRule
Published
2026-08-14
Updated
2026-08-28

ATT&CK techniques

Lateral Movement → C2
  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Collection

  11. Exfiltration

  12. Impact

What it detects

This rule detects command lines that tunnel TCP port 3389 which exposes internal Remote Desktop Protocol to the internet. The BlackJack group used ngrok tcp 3389 to reach RDP on compromised hosts, and such tunneling enables covert lateral movement and remote interactive access.

Related detections9 linkedT1021.001 — drag to rearrange
Obfuscated RDP Tunneling Configuration Enabled for Port Forwarding (via process_creation)
Malicious RDP Tunneling (via rdp)
Port Forwarding via SSH.EXE on Windows
Windows svchost.exe RDP (3389) Connections to HTTP/HTTPS Ports 80 or 443
Windows Plink Remote Port Forwarding via -R Command Line
Windows svchost RDP via Reverse SSH Loopback Tunnel to 127.0.0.0/8:3389
Suspicious Plink SSH Tunnel Execution (via process_creation)
Chisel Reverse Tunnel Tool Execution from Temporary Directory
Suspicious Remote Desktop Enabled via fDenyTSConnections Registry by Sandworm
Possible Ngrok RDP Tunnel Exposure via TCP 3389
Pivot detection · T1021.001 · 9 related

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