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 Host Firewall Flush via iptables (via process_creation)

Suspicious Firewall Port Opening via Netsh

Suspicious Host Firewall Disable via Iptables and UFW (via process_creation)

Suspicious Windows Firewall Rule Creation Masquerading as Network Discovery (via process_creation)

Suspicious Firewall Flush via iptables in Kinsing Intrusion

Suspicious Firewall Rule Allowing SSH via New-NetFirewallRule During Ransomware

Suspicious iptables Port Redirect Rule via GRIMBOLT

Suspicious Firewall Allow Rule for TightVNC Server via netsh (via process_creation)

Suspicious Firewall Rule Added to Open RDP Port 3389 via netsh

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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