Hi, Danny. I'll be glad to help you today.
NT authority accounts are related to Windows security and workgroup is a concept for environment where Active Directory is not necessary, All Windows computers by default belong to a workgroup called "workgroup".
By default, Windows keeps track of basic security operations. Impersonation does not represent in itself a security violation, since multiple processes in Windows perform this operation. It should be noted that this and other security methods in Windows can be used by an attacker.
It is always recommended, to be safe:
Avoid installing pirated applications
Do not install applications from unreliable manufacturers
Keep Windows up to date
Avoid visiting potentially risky internet sites
Please let me know if you need any further assistance.