CHAIN-104 — ExpressRoute without MACsec + carrier compromise

Summary

Severity: High · Likelihood: Low · Logic: ALL

Why this chain matters

ExpressRoute circuit does not enable MAC Layer Security. Traffic between corporate edge and Azure travels clear through the carrier's network. A carrier-level adversary (or compromised physical cross-connect) can sniff or inject.

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_023	Trigger
zt_net_002	Trigger

Attack walkthrough

Step 1 — Tap the ExpressRoute path at the MMR.

Actor: Carrier-level adversary
MITRE ATT&CK: T1040
Enabled by: zt_net_023

Attacker gain: Plaintext traffic stream.

Step 2 — Harvest session tokens; inject forged responses.

Actor: Adversary
MITRE ATT&CK: T1557
Enabled by: zt_net_002

Attacker gain: Full traffic compromise.

Blast radius

Initial access	Carrier-level access.
Max privilege	All ExpressRoute traffic.
Data at risk	All VNet-to-on-prem traffic
Services at risk	Everything traversing this circuit

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.