The npm package @years19/n8n-nodes-utils-helper-u version 1.0.0 contains malicious code that executes during installation and when the package is required. It writes and runs a Python script that launches a UDP/TCP flood attack against a hardcoded IP address for 600 seconds, effectively turning the host into a DDoS source. The code also collects host identifiers, encodes them, and sends them to a remote server without verifying the TLS certificate.