Suspicious Outbound Firewall Block Rule Added via Netsh Advfirewall

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 netsh advfirewall being used to add a rule that blocks outbound traffic, a technique observed in the ESXi intrusion to sever host communication with external security or management services. Attackers block outbound connections to prevent EDR telemetry and updates from reaching the network. An added block rule targeting outbound direction on a server is an atypical administrative action worth reviewing.

Reporting behind it

Related detections9 linkedT1686 — drag to rearrange

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Suspicious Outbound Firewall Block Rule Added via Netsh Advfirewall

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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