**Service category:** Entra Connect
**Product capability:** Access Control
As part of ongoing security hardening, Microsoft has implemented new safeguards to block account takeover attempts via hard match abuse in Microsoft Entra Connect (known as SyncJacking). Enforcement of this change begins in March 2026.Â
What’s Changing:Â
- Enforcement logic now checks OnPremisesObjectIdentifier to detect and block remapping attempts.Â
- Audit logs have been enhanced to capture changes to OnPremisesObjectIdentifier and DirSyncEnabled.Â
- Admin capability added to clear OnPremisesObjectIdentifier for legitimate recovery scenarios.Â
Customer Action Required:Â
- Upgrade to the latest Microsoft Entra Connect version.Â
- Review updated hardening guidance and enable recommended flags:Â Â
- Disable [hard match takeover](/powershell/module/microsoft.entra.directorymanagement/set-entradirsyncfeature?view=entra-powershell&preserve-view=true)Â
**Service category:** Entra Connect
**Product capability:** Access Control
When Microsoft Entra Connect adds new objects from Active Directory, the Microsoft Entra ID service tries to match the incoming object with an Entra object by looking up the incoming object’s [sourceAnchor value against the OnPremisesImmutableId attribute](../identity/hybrid/connect/how-to-connect-install-existing-tenant?source=recommendations.md#hard-match-vs-soft-match) of existing cloud managed objects in Microsoft Entra ID. If there's a match, Microsoft Entra Connect Sync takes over the source or authority (SoA) of that object and updates it with the properties of the incoming Active Directory object in what is known as "hard-match."
As part of ongoing security hardening, Microsoft is going to introduce enforcement changes in Microsoft Entra Connect to mitigate the risk of account takeover via hard match abuse. Enforcement of this change will begin on **July 1, 2026**.
**What’s Changing:**
- Microsoft Entra will block attempts by Entra Connect to modify the OnPremisesObjectIdentifier attribute after it has already been set on a synced user object. This prevents re‑mapping an existing Entra ID user to a different on‑premises identity.
- [Audit logs](../identity/monitoring-health/reference-audit-activities.md#core-directory) have been enhanced to capture changes to OnPremisesObjectIdentifier and DirSyncEnabled, enabling better visibility into synchronization behavior.
- To support [legitimate](../identity/hybrid/connect/how-to-connect-migrate-groups.md) scenarios where an existing hard match must be corrected, Microsoft has introduced a Microsoft Graph API that allows controlled recovery actions, without re‑enabling hard‑match abuse or unauthorized re‑mapping.
**What's Not Changing:**
- This enforcement applies only to scenarios where OnPremisesObjectIdentifier is being modified after it has already been set. Hard match functionality using [onPremisesImmutableId](../identity/hybrid/connect/plan-connect-design-concepts.md#sourceanchor) remains supported and unchanged. Customers can continue to perform initial hard matches as before.
**Customer Action Required:**Â