CHAIN-064 — On-prem sync admin compromises cloud

Summary

Severity: Critical · Likelihood: Medium · Logic: ALL

Why this chain matters

Entra Connect server holds a synchronization account that can write to the directory. The server is domain-joined and shares local admins with other workstations. Compromise the workstation → dump LSASS → own the sync account → write to Entra directly.

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_017	Trigger
zt_id_018	Trigger

Attack walkthrough

Step 1 — Run Mimikatz to extract cached credentials of a shared local admin.

Actor: Attacker on workstation
MITRE ATT&CK: T1003.001
Enabled by: zt_id_017

Attacker gain: Sync-server local admin credential.

Step 2 — Impersonate sync account; write directly to Entra via MSOL account token.

Actor: Attacker on Connect server
MITRE ATT&CK: T1098
Enabled by: zt_id_018

Attacker gain: Directory write access bypassing Conditional Access.

Blast radius

Initial access	Compromised on-prem workstation.
Max privilege	Directory write — equivalent to tenant admin.
Data at risk	Entire hybrid directory
Services at risk	Entra Connect + Entra ID

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.