T1078.001

Author: Stefan Waldvogel

LimaCharlie vs. External Remote Services

Overview:
Description from ATT&CK
Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Default accounts are those that are built-into an OS, such as the Guest or Administrator accounts on Windows systems. Default accounts also include default factory/provider set accounts on other types of systems, software, or devices, including the root user account in AWS and the default service account in Kubernetes.(Citation: Microsoft Local Accounts Feb 2019)(Citation: AWS Root User)(Citation: Threat Matrix for Kubernetes)
Default accounts are not limited to client machines, rather also include accounts that are preset for equipment such as network devices and computer applications whether they are internal, open source, or commercial. Appliances that come preset with a username and password combination pose a serious threat to organizations that do not change it post installation, as they are easy targets for an adversary. Similarly, adversaries may also utilize publicly disclosed or stolen Private Keys or credential materials to legitimately connect to remote environments via Remote Services.(Citation: Metasploit SSH Module)
source: github.com/redcanaryco/atomic-red-team/tree/master/atomics

Commands:
Invoke-AtomicTest T1078.001 -ShowDetailsBrief
Invoke-AtomicTest T1078.001 -CheckPrereqs
Invoke-AtomicTest T1078.001 -GetPrereqs
Invoke-AtomicTest T1078.001

Invoke-AtomicTest T1566.001 -Cleanup

Changes:
-nothing necessary-

Commands:
net user #{guest_user} /active:yes
net user #{guest_user} #{guest_password}
net localgroup administrators #{guest_user} /add
net localgroup "Remote Desktop Users" #{guest_user} /add
reg add "hklm\system\CurrentControlSet\Control\Terminal Server" /v fDenyTSConnections /t REG_DWORD /d 0 /f
reg add "hklm\system\CurrentControlSet\Control\Terminal Server" /v "AllowTSConnections" /t REG_DWORD /d 0x1 /f

Limitations:
-none-

Result:

Clearly visible in the event logs.

Additional info:
Command to enable logging on Win 10 Pro.
auditpol /set /subcategory:"computer account management" /Success:Enable /Failure:Enable

Next: T1078.003