The most common way to exploit this is through the Metasploit Framework.
Because this vulnerability is a classic example of a backdoor, it is widely used in ethical hacking education, particularly in environments like Metasploitable. Several GitHub repositories exist to demonstrate this exploit: 1. Python Exploit Script vsftpd 208 exploit github link
If a user attempts to log in to an affected FTP server and provides a username that ends with the characters :) (a smiley face), the backdoor triggers. The most common way to exploit this is