CHAIN-169 — Event Grid Domain with wildcard subscription filter

Summary

Severity: Medium · Likelihood: Medium · Logic: ALL

Why this chain matters

An Event Grid Domain has a subscription filter using wildcard * matching. A new event with attacker-controlled fields reaches every subscriber. Combined with a subscriber that trusts field content blindly, this becomes an injection vector.

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_int_003	Trigger
zt_int_006	Trigger

Attack walkthrough

Step 1 — Publish event with crafted fields.

Actor: Event publisher
MITRE ATT&CK: T1565.001
Enabled by: zt_int_003

Attacker gain: Event reaches every subscriber.

Step 2 — Interprets attacker-controlled field as command parameter.

Actor: Unsafe subscriber
MITRE ATT&CK: T1059
Enabled by: zt_int_006

Attacker gain: Code execution in subscriber context.

Blast radius

Initial access	Publish-side compromise.
Max privilege	Subscriber-context RCE.
Data at risk	Subscriber app state
Services at risk	All subscribers

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.