CHAIN-096 — Cosmos DB multi-region replication to wrong region

Summary

Severity: Medium · Likelihood: Low · Logic: ALL

Why this chain matters

Cosmos DB has a secondary replica in a region outside data-residency commitments. The replica is still ARM-addressable; a compromised principal targets the off-region endpoint which may have weaker VNet rules.

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_018	Trigger
zt_data_009	Trigger

Attack walkthrough

Step 1 — Enumerate Cosmos accounts; find the off-region writeable replica.

Actor: Attacker
MITRE ATT&CK: T1087
Enabled by: zt_data_018

Attacker gain: Replica endpoint with looser firewall.

Step 2 — Authenticate + read; same data as primary.

Actor: Attacker
MITRE ATT&CK: T1213
Enabled by: zt_data_009

Attacker gain: Read-path circumvention of the primary's hardening.

Blast radius

Initial access	Off-region endpoint exposure.
Max privilege	Cosmos read/write role.
Data at risk	Same content as primary
Services at risk	Cosmos DB

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.