Possible Firewall Rule Manipulation via netsh advfirewall by FishMonger

ATT&CK techniques

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

What it detects

This rule detects use of netsh to add advanced firewall rules, an action used by the FishMonger group to weaken host defenses and allow SprySOCKS communication. The technique modifies the Windows firewall configuration to permit inbound or outbound traffic for attacker tooling. Detecting this command is useful because unexpected firewall changes on endpoints can indicate defense evasion, though it also occurs during legitimate administration.

Reporting behind it

Related detections9 linkedT1686 — drag to rearrange

Suspicious netsh Firewall Rule Masquerading as SSTP HTTP

Suspicious Disabling of WinRM Service via sc config

Inbound C2 Firewall Rule Added via Netsh for TCP 5984

Suspicious Disabling or Flushing of the Linux Host Firewall (via process_creation)

Malicious Firewall Deactivation - PowerShell (via powershell)

Malicious Firewall Deactivation - Firewall (via firewall-as)

Suspicious Outbound Firewall Block Rule Added via Netsh Advfirewall

Malicious Windows Firewall Disable via Netsh

OpenSSH Server Firewall Configuration on Windows - Firewall (via firewall-as)

Possible Firewall Rule Manipulation via netsh advfirewall by FishMonger

Pivot detection · T1686 · 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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