Ensure you are running the latest stable version of VSFTPD maintained by your Linux distribution's package manager. Modern versions have completely excised compromised code and support secure FTPS configurations.
You do not always need a complex script from GitHub to verify this vulnerability in a safe, isolated lab environment (like Metasploitable 2). You can test it manually using netcat: vsftpd 2.0.8 exploit github
Most exploits found on GitHub for VSFTPD 2.0.8 target rather than flaws in the source code itself. If the server incorrectly configures write permissions for anonymous users, attackers can upload malicious scripts (like PHP web shells) to the web root directory. Anatomy of a VSFTPD Exploitation (GitHub PoC Style) Ensure you are running the latest stable version