MAL-2026-12903 Malicious code in bnpl-blocks-atom-desktop-bnpl-text (npm)

On require(), index.js unconditionally loads _polyfill.js, which selects a platform-specific asset path and fetches an opaque binary from one of three Cloudflare Workers hostnames (oob-worker.cf102-baf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf103-070.workers.dev), with a DNS-TXT fallback resolving subdomains of wel1.ru. The C2 hostnames are assembled at runtime from split string fragments joined with.join('') to evade literal string matching. The fetched bytes are written to /var/tmp or %TEMP% under a disguised name (.cache_<hex> on POSIX, dotnet_diag_<hex>.exe on Windows) mimicking a.NET diagnostic tool, chmod'd to 0755, and spawned detached via /bin/sh -c '<path> &' or cmd. Execution is gated by a stamp file and environment opt-outs to reduce observability. The package advertises a trivial text-abstraction layer with no legitimate need for a native binary or platform-specific asset delivery.