Unauthorized accounts must not have the Replace a process level token user right.
Inappropriate granting of user rights can provide system, administrative, and other high-level capabilities.
The "Replace a process level token" user right allows one process or service to start another process or service with a different security access token. A user with this right could use this to impersonate another account.
How this relates to the STIG checklist: STIG vs SCAP benchmark.