What breaks when service accounts and inactive users are not identified during IAM projects?

Why This Matters for Security Teams

Missed service account and inactive users are not just cleanup defects. They create hidden access paths that survive migration, distort entitlement baselines, and make access reviews look cleaner than they are. In IAM projects, that means the target state can inherit stale privilege, unresolved ownership, and accounts no one is watching. NIST’s Security and Privacy Controls emphasise account management as a core control family, but execution fails when discovery is incomplete.

NHI Management Group research shows the scale of the problem is often underestimated: only 5.7% of organisations have full visibility into their service accounts, while 97% of NHIs carry excessive privileges. That gap helps explain why access governance can look compliant on paper and still leave exposed accounts in production. The same issue appears in incident research such as the 52 NHI Breaches Analysis, where overlooked identities repeatedly become durable attack paths. In practice, many security teams discover these accounts only after a migration has already copied them forward into the new environment.

How It Works in Practice

IAM projects usually break down when discovery is treated as a one-time inventory exercise instead of a lifecycle control. Service accounts often sit outside HR-linked identity processes, while inactive users can remain enabled because their entitlements are still attached to applications, shared mailbox workflows, or delegated admin functions. If the project only reconciles active directory objects, it misses the accounts that matter most to attackers and auditors.

A better approach is to classify identities before migration or remediation begins. That means separating human users, dormant users, service accounts, shared accounts, break-glass accounts, and orphaned technical identities. Each class needs different ownership, review cadence, and deprovisioning logic. For service accounts, teams should assign a business or application owner, document the purpose, and tie the account to a renewal or rotation cycle. For inactive users, the question is whether the account should be disabled, archived, or converted into a controlled exception.

• Use source system data, authentication logs, and directory metadata together to find accounts that have not logged in but still hold privilege.
• Map each account to an owner and a purpose before moving it into the target IAM model.
• Validate whether the account is still required by an application, scheduled job, API integration, or vendor workflow.
• Remove unnecessary privilege before migration so stale access is not normalised in the new design.

This matters because hidden technical accounts often become the shortest path to privilege escalation, especially when secrets are reused or never rotated. NHIMG’s Ultimate Guide to NHIs notes that only 20% of organisations have formal offboarding and revocation processes for API keys, which is why decommissioning cannot be left to the end of a project. These controls tend to break down when legacy applications depend on unmanaged shared credentials because ownership cannot be proved quickly enough to revoke access safely.

Common Variations and Edge Cases

Tighter access cleanup often increases project friction, requiring organisations to balance reduced attack surface against application downtime and business disruption. That tradeoff is real when identity records are incomplete, because disabling the wrong account can break batch jobs, integrations, or vendor-managed workflows.

Best practice is evolving, but current guidance suggests handling edge cases with documented exceptions rather than leaving questionable accounts permanently enabled. Shared accounts, inherited admin IDs, and dormant break-glass accounts should be time-bound, monitored, and reviewed separately from ordinary user populations. In cloud and DevOps environments, some inactive-looking accounts are actually automation principals, so a simple inactivity rule is not enough.

Where teams fail most often is not in identifying obvious users, but in recognising technical identities that never pass through the human joiner-mover-leaver process. That is why service account discovery should be paired with secret inventory, application dependency mapping, and post-cutover validation. NHIMG’s reporting on secrets exposure, including the JetBrains GitHub plugin token exposure, shows how quickly overlooked credentials can become active compromise paths. When environments rely on local scripts, embedded tokens, or distributed admin sprawl, even a strong cleanup process can miss accounts that are technically inactive but operationally still live.

Related resources from NHI Mgmt Group

• What breaks when identity data from service accounts, policies, and events is not normalised before analysis?
• What breaks when shared local administrator accounts are not tied to individual users?
• What problem does ownership attribution solve for service accounts and API keys?
• When do service accounts become a higher risk than ordinary user accounts?