CHAIN-120 — Function App with over-privileged Graph permission

Summary

Severity: High · Likelihood: Medium · Logic: ALL

Why this chain matters

A Function App is granted Directory.ReadWrite.All via its managed identity — the developer couldn't figure out the least-privilege scope. Any prompt-injection / template-injection / upstream-library-compromise against the function gives attackers tenant-wide directory write.

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_wl_002	Trigger
zt_id_011	Trigger

Attack walkthrough

Step 1 — Exploit injection vuln in function HTTP handler.

Actor: Attacker
MITRE ATT&CK: T1190
Enabled by: zt_wl_002

Attacker gain: Code execution with function MI.

Step 2 — Use MI's Directory.ReadWrite.All to create admin users.

Actor: Attacker
MITRE ATT&CK: T1098
Enabled by: zt_id_011

Attacker gain: Tenant admin persistence.

Blast radius

Initial access	Function-app vuln.
Max privilege	Tenant directory write.
Data at risk	All directory objects
Services at risk	Entra ID

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.