BYOSI (Bring-Your-Own-Script-Interpreter) is a technique that allows attackers to deliver a malicious script interpreter and source code to a target system, which can then be executed by the trusted script interpreter. PolyDrop is a tool that leverages 13 scripting languages to perform this attack. Many antivirus vendors, including MS-Defender, fail to detect malicious scripts in languages such as tcl, php, crystal, and julia. These languages are often ignored by AV vendors, allowing attackers to execute malicious code undetected. PolyDrop is currently undetectable by most mainstream Endpoint-Detection & Response vendors. Many vendors are unable to scan or process PHP file types, and even more are unable to accurately identify malicious PHP scripts. The maintainers of PolyDrop claim that their tool is for legitimate penetration testing and educational purposes only and are not responsible for its misuse. The tool is modular and designed to be updated with new features in the future. Users are advised to use the tool responsibly and in accordance with applicable laws. PolyDrop is available for download.