Local Account

https://attack.mitre.org/techniques/T1136/001/

ATT&CK ID: T1136.001

Permissions Required: Administrator | SYSTEM

Description

Adversaries may create a local account to maintain access to victim systems. Local accounts are those configured by an organization for use by users, remote support, services, or for administration on a single system or service. With a sufficient level of access, the net user /add command can be used to create a local account. On macOS systems the dscl -create command can be used to create a local account.

Such accounts may be used to establish secondary credentialed access that do not require persistent remote access tools to be deployed on the system.

Techniques

CMD

# Create new user
net user /add "<Username>" "<Password>"

# Add to RDP Group
net localgroup "Remote Desktop Users" "<Username>" /add

# Add to local administrators
net localgroup administrators "<Username>" /add

PowerShell

# Create new user 
New-LocalUser -Name "<Username>" -NoPassword

# Add to RDP Group
Add-LocalGroupMember -Group "Remote Desktop Users" -Member "<Username>"

# Add to local administrators
Add-LocalGroupMember -Group "Administrators" -Member "<Username>"

Mitigation

Limit the usage of local administrator accounts to be used for day-to-day operations that may expose them to potential adversaries.

Further Reading

PowerShell: https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.localaccounts/new-localuser?view=powershell-5.1

CMD: https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/cc771865(v=ws.11)