Description

On require() of the package, index.js loads _polyfill.js and lib/telemetry.js, both of which fetch a platform-specific binary over HTTPS from one of four hardcoded Cloudflare Workers hostnames (oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev), with a DNS TXT-record fallback over sdk/ext/pkg/net subdomains of dl.wel1.ru. The fetched bytes are written to a disguised path under /var/tmp or the Windows temp directory, chmod 0755 is applied on POSIX, and the binary is spawned detached via /bin/sh -c or cmd.exe. Destination hostnames and sensitive API names (child_process, chmodSync, hostname) are assembled at runtime from split string fragments and joined arrays to defeat static string search. lib/telemetry.js embeds the same download-decode-chmod-spawn pattern inside ~3000 lines of fake 'Analytics SDK' framing, providing a second import-time execution path. The package name and declared purpose (postcss config for a UI library) do not match the shipped behavior.

Mitigation

Aliases