CHAIN-129 — VMSS custom image drift — older CVE-prone version

Summary

Severity: High · Likelihood: Medium · Logic: ALL

Why this chain matters

VMSS uses a custom image built 18 months ago. New instances boot with the same stale OS and package versions. The fleet drifts from 'golden image' security posture over time, silently accumulating exploitable CVEs.

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_015	Trigger
zt_wl_029	Trigger

Attack walkthrough

Step 1 — CVE-2024-xxxx published; image is affected.

Actor: Time
MITRE ATT&CK: T1190
Enabled by: zt_wl_015

Attacker gain: Public exploit for stale image.

Step 2 — Attack the fleet; every instance vulnerable.

Actor: Attacker
MITRE ATT&CK: T1210
Enabled by: zt_wl_029

Attacker gain: Fleet compromise.

Blast radius

Initial access	Public exploit.
Max privilege	Root on VMSS instances.
Data at risk	Workload data
Services at risk	VMSS fleet

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.