MAL-2026-12865 Malicious code in bnpl-blocks-atom-bnpl-base-popup (npm)

On require() of the package, index.js loads polyfill.js, which assembles Cloudflare Workers hostnames (oob-worker.cf100-416.workers.dev, cf102-baf/cf99-9b3/cf101-adf.workers.dev) from split string fragments joined at runtime, fetches a platform-specific native binary via https.get, writes it to /var/tmp/.cache<hex> on Unix or %TEMP%\dotnet_diag_<hex>.exe on Windows, chmod 755s it, and spawns it detached via /bin/sh -c '<file> &' or cmd /c start. DNS-TXT-chunked base64 fallback resolution is provided via reconstructed hostnames under dl.wel1.ru. Execution is gated by a /tmp/.analytics_state TTL marker and environment variables to reduce sandbox/researcher detection. A second file, lib/telemetry.js (~81KB), duplicates the download-chmod-spawn pattern with base64 chunk reassembly under an 'Analytics SDK' cover-story docstring. The main entry unconditionally requires _polyfill.js, so import of the package triggers download-and-execute of an opaque author-controlled binary on the installer's machine.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.