The Active Directory user you create for a service account must be enabled for authentication to work. However, enabling this new user account does present some potential risks to your environment. For example, on UNIX computers, creating the new user may have added a password for a service account that did not previously have one. If the new password is known to more than one person, the account may be considered a shared account and result in an audit finding.
Also, because the new account is a valid Active Directory user principal, anyone with the password can potentially log on to any Windows computer in the forest. By giving the service account a valid password and enabling the account, you have granted access to the Windows network for an account that previously had no access to Windows computers.
If you disable the account, you prevent that account from accessing all Windows and UNIX computers, running jobs, or executing required tasks. If you leave the account enabled and the password is compromised, both Windows and UNIX computers are vulnerable to attack. Even if the password is not compromised, failed password attempts could trigger an account lockout policy, rendering the service unusable.
Mapping service accounts to Active Directory users is a simple technique for managing access and password complexity for service accounts. If you have strong passwords and carefully control access to the account and its password, you can mitigate the risks. This strategy is also best suited to service accounts that already use a password. However, if granting the service account access to the Windows network presents too great of a risk, you should consider alternatives.