Operation Friday Harvest npm Postinstall Shell Spawn with Temp File Drop

Ibrahim Saud@tektrix

•updated Jun 24, 2026•0•0•1

This rule detects potential supply chain attacks where a Node.js process (npm, npx, node) triggers an unauthorized shell, scripting interpreter, or network utility (such as curl, wget, powershell, or bash) to execute commands. This behavior, when followed by file creation in temporary directories (e.g., /tmp, AppData\Local\Temp) within a 5-minute window, is indicative of malicious npm postinstall hooks, commonly seen in supply chain compromise campaigns.