Threat Intelligence

Forgotten Service Accounts Leave Microsoft 365 Environments Exposed

Dark Reading · 24 Sept 2026

Key Takeaway Regularly audit all Microsoft 365 accounts, including service and automation accounts, to identify and disable any that are unused or unmonitored.

Security researchers have highlighted a case in Chile where attackers exploited forgotten or unmanaged service accounts within Microsoft 365 to access and steal organisational data. These "ghost" accounts are often created for automated tasks, integrations, or legacy systems and can be left active long after they're needed, with weak oversight and no ongoing monitoring.

The issue is that organisations frequently focus their security efforts on human user accounts, applying multi-factor authentication and password policies, while service accounts fall outside these controls. Attackers who discover these dormant credentials can quietly access sensitive systems and data, undermining even well-secured employee account setups.

This case is a reminder that a business's overall security posture is only as strong as its weakest, most overlooked access point.

Microsoft 365 service accounts data theft identity security cloud security

Summarised by CISO AI from Dark Reading. We link back to every original so you can read it yourself.