MAL-2026-12945 Malicious code in bnpl-blocks-desktop-bnpl-title (npm)

The package's main entry (index.js) requires support.js on load. support.js selects a platform-specific path, then downloads a binary over HTTPS from Cloudflare Worker hostnames that are reconstructed at runtime by joining split string fragments (oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev). If HTTPS retrieval fails, a fallback channel uses DNS TXT queries against *.dl.wel1.ru (c.<domain> for chunk count, i.<domain> for base64-encoded chunks) to reassemble the payload out-of-band. The downloaded bytes are written to /var/tmp or %TEMP% under deceptive names such as dotnet_diag<rand>.exe and.cache<rand>, chmod'd 0755, and executed detached via /bin/sh -c "<path> &" or cmd.exe /c start. No hash or signature verification is performed. The advertised purpose ("bnpl title provider") has no relation to any of this behavior. A second file, lib/telemetry.js, is not currently required but contains structurally identical dropper primitives (base64 payload assembly, chmod 0755 via bracket-split property name, /bin/sh detached spawn of a downloaded file), staged for activation by a one-line require change.