MAL-2026-13248 Malicious code in bigops-rx-post-message (npm)

On require() of bigops-rx-post-message, index.js executes init.js at module top level, which downloads a platform-specific binary from Cloudflare Workers hosts whose names are assembled at runtime from string-split arrays (e.g. oob-worker.cf10x-*.workers.dev) with a DNS-TXT base64 fallback across sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched bytes are written under /var/tmp or %TEMP% with a disguised name (.cache<hex> / dotnet_diag_<hex>.exe), chmodded 0755, and spawn-detached via /bin/sh -c or cmd.exe. No hash or signature verification is performed, the destinations are not the publisher's infrastructure, and lib/telemetry.js contains the same dropper primitives with child_process obtained via string concatenation (require("child_"+"process")) and fs["chmod"+"Sync"] indexed by string to evade static scanners. Installing or requiring this package causes an unpinned, attacker-controlled executable to run on the installer's host.