CHAIN-079 — Cosmos DB account key exposed in App Service config

Summary

Severity: High · Likelihood: High · Logic: ALL

Why this chain matters

Cosmos DB is accessed via master account key stored in App Service application settings. The key is readable by anyone with Website Contributor and grants root access to the entire Cosmos account. Managed identity would sandbox this; the developer chose the shortcut.

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_data_007	Trigger
zt_wl_017	Trigger

Attack walkthrough

Step 1 — Read app settings; find CosmosDBKey value.

Actor: Attacker with Website Contributor
MITRE ATT&CK: T1552.001
Enabled by: zt_wl_017

Attacker gain: Valid Cosmos master key.

Step 2 — Use key via Cosmos SDK; full read + delete on every container.

Actor: Attacker
MITRE ATT&CK: T1565.001
Enabled by: zt_data_007

Attacker gain: Unrestricted database access.

Blast radius

Initial access	App Service config read.
Max privilege	Cosmos DB root.
Data at risk	Every Cosmos container in the account
Services at risk	Cosmos DB, Dependent app state

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.