Move Windows services from reusable passwords to managed service identities where supported

Source facts: a gMSA moves password management to the domain

Microsoft’s group Managed Service Account management guidance describes gMSAs as domain accounts usable by services on multiple domain-joined servers. The domain controller manages the password and authorized hosts retrieve it, removing ordinary administrator handling of a reusable service-account password. Microsoft also describes simplified service principal name management.

The gMSA overview explains the role of the Key Distribution Service and the use of one service principal across a server farm where mutual authentication is required. It lists operating-system and Active Directory prerequisites and distinguishes group managed, standalone managed, virtual, and ordinary user accounts.

A gMSA is not supported by every Windows service, installer, scheduled task, cluster, application, database, or third-party product. It does not automatically remove excessive privileges, insecure delegation, weak file permissions, exposed connection strings, or application secrets. Domain version, KDS configuration, product support, backup, and recovery must be verified for the environment.

DSE recommendation: migrate an identity as an application change

Build a service-identity register before creating accounts. For each current account, identify owner, services and tasks, hosts, SPNs, logon rights, local groups, file and registry access, shares, databases, certificates, APIs, scheduled jobs, dependent systems, password-change method, recovery process, and last verified use. Do not infer scope from the account name.

Confirm support. Obtain current vendor documentation for the exact application and version. Verify whether it accepts a gMSA, how the account is entered, whether a blank password is supported, and any limitations for clusters, services, tasks, application pools, installers, upgrades, or remote resources.

Prepare the domain. Have qualified Active Directory administrators verify forest and domain prerequisites, KDS root-key state, time and replication, naming, DNS, and supported management tools. Avoid recreating or manipulating KDS material merely to accelerate a deployment.

Limit retrieval. Authorize only the computer accounts or controlled group of hosts that must retrieve the gMSA password. Protect the membership and monitor changes. An attacker controlling an authorized host may be able to use the service identity.

Rebuild least privilege. Grant only required logon rights, local membership, file, registry, share, database, network, and application permissions. Register only required SPNs and review delegation. Do not clone all permissions from an overprivileged legacy account for convenience.

Pilot and exercise. Migrate a supported noncritical instance in a change window. Test start, stop, restart, reboot, patching, dependency access, Kerberos authentication, failover, backup, restore, monitoring, log collection, and vendor upgrade. Preserve a time-bounded rollback.

Retire the legacy secret. After verification, remove the old account from service configuration, scheduled tasks, scripts, vaults, documentation, and permissions. Rotate its password to invalidate undiscovered copies, monitor attempted use, then disable and delete only under the approved retention and rollback policy.

Monitor service starts, failed logons, SPN conflicts, host-retrieval authorization changes, group membership, privilege changes, and use from unexpected systems. Include the gMSA in tiering and disaster-recovery plans: a restored service must still have domain connectivity, correct authorization, and required dependencies.

Do not force migration where the vendor does not support it. A vault-managed, narrowly privileged account with automated rotation may be the safer interim design. Success is not the presence of a dollar sign in an account name; it is removal of human-managed reusable credentials without breaking support, containment, or recovery.

Maintain an explicit noncandidate list with the vendor limitation, current protective controls, credential owner, rotation evidence, and next review trigger. Stop a pilot on unsupported installer behavior, inability to restore service, unexpected host retrieval, SPN conflict, or a permission request broader than the documented dependency. Return to the prior identity under the change plan and correct the design before attempting another service.

Official references

Microsoft, Manage group Managed Service Accounts.

Microsoft, Group Managed Service Accounts overview.