Malicious Reverse Tunnel Agent Execution with Hidden Server Flags

ATT&CK techniques

C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1572Protocol Tunneling
Exfiltration
Impact

What it detects

This rule detects execution of agent.exe with -server and -hide command-line flags, the reverse tunnel implant used in a Huntress-investigated Nightmare-Eclipse intrusion that connected to staybud.dpdns.org over port 443. The -hide flag conceals the agent window while -server points to the attacker relay, establishing a yamux-based reverse tunnel. This flag combination reflects covert command-and-control tunneling.

Reporting behind it

Related detections9 linkedT1572 — drag to rearrange

Suspicious DNS Query to Dynamic DNS and Tunneling Providers Abused by RATs

Suspicious SSH Reverse Tunnel Over DNS Port

Suspicious Reverse SSH Tunnel Exposing Local SSH via process_creation

Suspicious OpenSSH Reverse Tunnel Creation via Process Creation

Suspicious OpenSSH Reverse Tunnel Establishment via process_creation

Suspicious LocalToNet Tunneling Tool Execution

Malicious RDP Tunneling via ngrok (via process_creation)

Suspicious UUID Named Pipe Created Consistent with Mythic SMB Agent

Malicious Chisel Reverse Tunnel Execution for Protocol Tunneling

Malicious Reverse Tunnel Agent Execution with Hidden Server Flags

Pivot detection · T1572 · 9 related

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

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