CHAIN-134 — Spot VM + unhandled eviction exposes running data

Summary

Severity: Low · Likelihood: Medium · Logic: ALL

Why this chain matters

Spot VMs are evicted with 30-second notice; apps that don't checkpoint leave in-memory data in page files on the VHD. If disk encryption isn't enforced for ephemeral OS disks, a later attacker-controlled Spot allocation reuses the same hardware and can potentially recover residual data.

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_022	Trigger
zt_data_015	Trigger

Attack walkthrough

Step 1 — Evict spot VM; data written to disk not fully wiped.

Actor: Azure infrastructure
MITRE ATT&CK: T1486
Enabled by: zt_wl_022

Attacker gain: Residual data on ephemeral storage.

Step 2 — Lucky-allocation yields the same underlying storage; extract residual data.

Actor: Attacker with new spot
MITRE ATT&CK: T1005
Enabled by: zt_data_015

Attacker gain: Cross-tenant data recovery.

Blast radius

Initial access	Luck + spot allocation.
Max privilege	Historical data residual.
Data at risk	Previous workload memory state
Services at risk	Spot VM consumers

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.