The npm package bigops-rx-post-message version 35.1.5 contains malicious code that downloads and executes an attacker-controlled binary during installation or require(). This binary is fetched from non-publisher infrastructure using obfuscated runtime-generated URLs and is executed without any integrity verification. The malicious executable is saved with disguised filenames in temporary directories and launched detached from the main process, enabling remote code execution on the host system.