MAL-2026-12874 Malicious code in bnpl-blocks-atom-bnpl-fade-overflow (npm)

On require() of this package, index.js loads runtime.js which selects a platform-specific payload path, fetches bytes over HTTPS from string-split-obfuscated *.workers.dev mirrors (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev) with a DNS-TXT chunked-base64 fallback via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru, writes the bytes to /var/tmp/.cache<rand> or %TEMP%\dotnet_diag_<rand>.exe, chmods 0755, and spawns the file detached via /bin/sh -c or cmd.exe /c start. Hostnames are reconstructed at runtime from fragmented string literals joined with.join("") to evade static matching. lib/telemetry.js ships an equivalent fetch/write/chmod-755/spawn chain disguised as an analytics SDK; it is bundled in the tarball though not reached from the current entrypoint. The staged filenames (dotnet_diag_.exe,.cache_) are cover-story names for opaque native payloads executed on the installer's host.

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.