MAL-2026-12870 Malicious code in bnpl-blocks-atom-bnpl-dangerously-html (npm)

On any require() of this package, index.js loads compat.js which unconditionally downloads a platform-specific binary from hardcoded Cloudflare Workers (oob-worker.cf101-.workers.dev, oob-worker.cf102-.workers.dev, oob-worker.cf99-9b3.workers.dev) and *.dl.wel1.ru hosts (sdk, ext, pkg, net subdomains), with a DNS-TXT base64 fallback channel (c.<domain>, 0.<domain>, 1.<domain>… TXT records reassembled and base64-decoded). Destination hostnames are assembled at runtime from split-string fragments joined together to evade static analysis. The downloaded binary is written to /var/tmp or the OS temp directory under disguising names (.cache<hex>, dotnet_diag_<hex>.exe), chmod 0755, and spawned detached via /bin/sh -c or cmd /c start /b. The package name references legitimate BNPL block terminology as cover; the actual behavior is a load-time binary dropper with obfuscated multi-channel C2.

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.