CHAIN-105 — NAT gateway with outbound any + data exfil channel

Summary

Severity: Medium · Likelihood: Medium · Logic: ALL

Why this chain matters

NAT gateway allows outbound to any destination and the VNet has no egress monitoring. A compromised VM can exfiltrate to attacker DNS or HTTP servers without triggering any network alert.

Component rules

This chain fires when its trigger conditions are met by the following rules. Click any rule to see its detection logic and compliance mappings.

Rule ID	Role
zt_net_024	Trigger
zt_vis_001	Trigger

Attack walkthrough

Step 1 — DNS-tunnel data to attacker.com via NAT gateway.

Actor: Compromised VM
MITRE ATT&CK: T1048.003
Enabled by: zt_net_024

Attacker gain: Data leaving via unmonitored egress.

Step 2 — Reassemble tunnelled data at C2 server.

Actor: Attacker
MITRE ATT&CK: T1041
Enabled by: zt_vis_001

Attacker gain: Slow-drip exfiltration, undetected.

Blast radius

Initial access	Any VM compromise.
Max privilege	Covert exfil channel.
Data at risk	Anything reachable by VM
Services at risk	Any private resource the VM can read

How the logic works

The chain fires only when every rule above has at least one finding in the current scan. Missing any one rule breaks the chain — so remediating any single step disrupts the attack path.