Users being added in my non admin account in admin group

i feel like NTAUTHORITY was a thing in XP maybe 7 but they stopped it because it was a way to hack. I know its to do with system level stuff but there is not much information online i can wrap my head around tbh.

I could be just thinking this but i don't think its common to see the user name or it might of got renamed in later versions of windows. The web searches are kind of suggesting that it is not common else you would be able to find the right information or even someone else talking along the same lines.

Malneb said:

-Local user as in the account you are signed into
-SYSTEM
-LOCAL SERVICE
-NETWORK SERVICE
-ANONYMOUS USER
-DWM1
-UMFD-0

These are the only users that are running stuff on my computer atm.

How do i check that i cant figure out how to "in task manager and see if there is any applications running under the NTAUTHORITY user"

Details tab.

Say NTAUTHORITY\System would be the old way to what we call SYSTEM user now i think not certain and SYSTEM is already defined it has no need to be in the Administrators group and i think it is on par or has slightly higher perms than Administrators but basically full control there is a chart but can't recall where it is.

Regardless i don't think NTAUTHORITY\Whatever should be inside Administrators group. I don't know this for certain and that image you linked is saying that those other sub users of NTAUTHORITY should not be elevated like that.

There is another guy asking this and the one answering have never seen this happen before.

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Malneb said:

Say NTAUTHORITY\System would be the old way to what we call SYSTEM user now i think not certain and SYSTEM is already defined it has no need to be in the Administrators group and i think it is on par or has slightly higher perms than Administrators but basically full control there is a chart but can't recall where it is.

Regardless i don't think NTAUTHORITY\Whatever should be inside Administrators group. I don't know this for certain and that image you linked is saying that those other sub users of NTAUTHORITY should not be elevated like that.

Exactly! Something is adding it when i log in automatically. I need to pinpoint what is adding it, is there a way to pinpoint it in event viewer? Where should i search in event viewer to find out?

Securuity auditing in event viewer will show audits on groups and users.

Windows Log > Security.

That still does not explain why they are having these users in their admin group, its irrelevant i mentioned try disabling the DefaultAccount forgetting that it is disabled by default its not even relevant anyway its about multi user applications so like Xbox games and stuff like this would make use of that sort of feature but it means multil user parameters hence why i was on the line of thinking make sure its disabled.

Yes like look through those logs and see if you can work out the pattern that is happening you should be able to tell what those user accounts in question are doing at least in a vague sense.
Like example this one here i am reading on my computer is telling me that SYSTEM logged on and started the services.exe which looks like a normal sort of outcome.

Code:

An account was successfully logged on.

Subject:
	Security ID:		SYSTEM
	Account Name:		BEN-PC$
	Account Domain:		WORKGROUP
	Logon ID:		0x3E7

Logon Information:
	Logon Type:		5
	Restricted Admin Mode:	-
	Virtual Account:		No
	Elevated Token:		Yes

Impersonation Level:		Impersonation

New Logon:
	Security ID:		SYSTEM
	Account Name:		SYSTEM
	Account Domain:		NT AUTHORITY
	Logon ID:		0x3E7
	Linked Logon ID:		0x0
	Network Account Name:	-
	Network Account Domain:	-
	Logon GUID:		{00000000-0000-0000-0000-000000000000}

Process Information:
	Process ID:		0x3ec
	Process Name:		C:\Windows\System32\services.exe

Network Information:
	Workstation Name:	-
	Source Network Address:	-
	Source Port:		-

Detailed Authentication Information:
	Logon Process:		Advapi  
	Authentication Package:	Negotiate
	Transited Services:	-
	Package Name (NTLM only):	-
	Key Length:		0

This event is generated when a logon session is created. It is generated on the computer that was accessed.

The subject fields indicate the account on the local system which requested the logon. This is most commonly a service such as the Server service, or a local process such as Winlogon.exe or Services.exe.

The logon type field indicates the kind of logon that occurred. The most common types are 2 (interactive) and 3 (network).

The New Logon fields indicate the account for whom the new logon was created, i.e. the account that was logged on.

The network fields indicate where a remote logon request originated. Workstation name is not always available and may be left blank in some cases.

The impersonation level field indicates the extent to which a process in the logon session can impersonate.

The authentication information fields provide detailed information about this specific logon request.
	- Logon GUID is a unique identifier that can be used to correlate this event with a KDC event.
	- Transited services indicate which intermediate services have participated in this logon request.
	- Package name indicates which sub-protocol was used among the NTLM protocols.
	- Key length indicates the length of the generated session key. This will be 0 if no session key was requested.