MAL-2026-13008 Malicious code in bnpl-blocks-mobile-bnpl-table (npm)

On require of this package, main resolves to _runtime.js, which assembles Cloudflare Workers hostnames by string-splitting (oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev) and falls back to DNS TXT record retrieval under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru. The fetched platform-specific binary is written to /var/tmp/.cache_<hex> on Linux or %TEMP%\dotnet_diag_<hex>.exe on Windows, marked executable via fs.chmodSync(..., 0o755), and spawned detached through /bin/sh -c '<path> &' or cmd.exe /c start /b, with the child_process require and chmodSync call assembled by string concatenation to evade static matching. A second module, lib/telemetry.js (~80KB), is framed as an analytics SDK and duplicates the same write+chmod+spawn dropper primitives with identical string-split obfuscation; it is not reached from the current entrypoint but is present in the tarball as a dormant second stage. Cover filenames imitating cache and.NET diagnostic files, an environment-variable opt-out framed as a cover story, and rate-limiting all indicate deliberate concealment.