CHAIN-065 — Overprivileged device registration lets attacker bypass CA

Summary

Severity: High · Likelihood: Medium · Logic: ALL

Why this chain matters

Device registration is not restricted — any user in the tenant can register a new device. An attacker registers their attacker-controlled laptop as a 'compliant' device, then uses device-bound refresh tokens to satisfy the 'compliant device' Conditional Access requirement.

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_id_020	Trigger
zt_id_007	Trigger

Attack walkthrough

Step 1 — Register their laptop as a tenant device.

Actor: Attacker with stolen creds
MITRE ATT&CK: T1098.005
Enabled by: zt_id_020

Attacker gain: Fake-compliant device object.

Step 2 — Obtain PRT; use it to bypass CA policies that require compliant device.

Actor: Attacker
MITRE ATT&CK: T1550.001
Enabled by: zt_id_007

Attacker gain: Full session access to protected apps.

Blast radius

Initial access	Stolen corporate creds.
Max privilege	User level + CA bypass.
Data at risk	User's protected-app data (Teams, SharePoint, Exchange)
Services at risk	Entra device trust

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.