Previewed in 1999 and released in the spring of 2000, Active Directory turned 25 last year. And yet in a lot of enterprises, AD is still the identity backbone for employee users, Windows machines, legacy apps and critical on-prem infrastructure. Which means the “legacy” story is not really about AD itself. It’s about what still runs on top of it: service accounts as on-prem non-human identities. They power business-critical services, tend to stick around for years and multiply into a messy sprawl.
In this blog, we’ll break down what the on-prem NHI problem looks like in practice, what discovery and control should mean for AD service accounts, and how Entro integrates with AD to discover and classify service accounts, visualize access paths and permissions, and drive security for on-prem AD service accounts.
Enterprise Security for AI Agents & Non-Human Identities
AD Service Accounts: What They Are and Why They Still Matter
In Active Directory Domain Services (AD DS), service accounts are usually domain identities or “user objects” that Windows services, scheduled tasks, PowerShell scripts, and applications use to run with a consistent security context. Microsoft defines it simply: “A service account is a user account that’s created explicitly to provide a security context for services that are running on Windows Server operating systems”.
In many organizations, these on-prem non-human identities are provisioned as regular Active Directory user accounts, created and managed much like human user objects. They’re just assigned to a service and not a person. Some orgs use group managed service accounts or gMSAs instead, which are also domain identities but with password management handled by AD.
They still matter because they don’t behave like employees or being managed like ones, but they often carry elevated access. In practice, AD service accounts become a quiet on-prem control layer for workloads, integrations, and automation, and that layer rarely gets the same visibility or governance as human identities.
Where Active Directory NHIs Become a Problem
Post-breach, AD service accounts are often the identities attackers go after first, because they’re a clean path to persistence, lateral movement, and privilege escalation. The frustrating part is that the risk is rarely “one bad account”. It’s a few repeatable AD patterns that quietly pile up over time.
They outlive their purpose (and their creators)
Service accounts tend to stay enabled for years, long after the original app, project, or owner has moved on. Over time, they drift into more privileged territory and accumulate access through Organizational Unit (OU) scope, delegation, and Group Policy-driven local group assignments. In hybrid environments they can be also synced through Entra ID and have cloud permissions to cloud resources.
Critical access gets buried in nested groups
On paper, a service account might look “low risk”. In practice, it inherits powerful access rights through multi-level group membership, and the real effective permissions are several hops away.
Permissions sprawl across OUs and access controls
Delegated access, granular permissions, and inherited permissions sprawl across OUs and object ACLs/ACEs (an ACL is a list of ACEs, each ACE defines what a user/group/service account is allowed, denied, or audited to do on an object). That’s how “normal” directory changes quietly turn into unexpected access paths.
Humans and service accounts start swapping behaviors
AD security posture risks go both ways: humans get configured for programmatic use, while service accounts get used interactively as if they were human users. When you see service accounts touching RDP, console logons or showing up on unusual hosts, governance is already slipping.
No clear owner means slow remediation
Even when security spots the risk, teams hesitate: rotate, right-size, or disable the wrong account and you can break production. Without ownership and context, remediation turns into a game of chicken nobody wants to play.
Entro for On-Prem AD: From “Objects” to Governed NHIs
Working with our enterprise customers in AD-heavy environments, we kept seeing the same pains: it’s not that teams don’t know service accounts exist. It’s that they don’t have a clean, reliable way to handle and secure AD service accounts as NHIs, with clear visibility into effective access and a safe path to remediation.
That’s why we built this integration.
Entro’s platform connects to on-prem Active Directory and ingests AD objects, users and ACLs to map effective access (nested groups, OUs, ACEs, hybrid cloud roles) and highlight potential exposure paths. Then we tie those findings to ownership, anomaly and threat detection and remediation workflows so security and IAM teams can act without guesswork.
What this gives security and IAM teams, in practice:
- Bring service accounts into your NHI Security program: Stop treating on-prem AD as a “legacy exception.” Pull AD service accounts into the same inventory, posture and governance motion you apply to the rest of your cloud and SaaS NHIs.
- See effective access, not just direct membership: Expand nested groups and interpret OU scope plus ACL/ACE permissions so you can understand what a service account can actually touch, end to end.
- Visualize access paths and blast radius: Map how an identity reaches resources through groups, permissions, and inheritance, so investigations don’t start with guesswork.
- Add ownership so remediation becomes possible: Attribute service accounts to a responsible human or team, so rotation, right-sizing, and decommissioning can happen without “who’s going to break prod?” standoffs.
- Detect misuse and posture risks: Monitor service accounts behaving like humans (interactive logons) or humans behaving like service accounts, and flag anomalous patterns early.
- Remediate through playbooks and automation, not spreadsheets: Route findings into your existing processes and integrations, so fixing AD service account sprawl becomes operational, not heroic.
Deployment: Pick the Right Fit for Your AD Architecture
Entro lets you choose the deployment method that fits your environment. Options can be used independently or combined for richer context.
- Entra ID ingestion (synced on-prem): Ingest AD-related identity objects synchronized to Entra ID to accelerate baseline visibility in hybrid deployments.
- CrowdStrike (EDR context): Add domain controller + device context and identity activity signals to enrich service account behavior and usage analysis.
- Entro on-Prem Outpost: Connect directly to on-prem AD DS to ingest AD objects and ACLs/ACEs for deep permissions, effective access, and attack-path analysis.
Deployment is non-disruptive: Entro uses a dedicated read-only LDAP bind account and does not make changes to AD.
Ready to secure your “legacy” NHIs?Read our datasheet to learn more about Entro X AD integration or schedule a personalized demo with our experts to assess your on-prem Active Directory service account exposure, risks, and remediation paths.
