MAL-2026-12531 Malicious code in cardsmobile-data-utils (npm)

On require() of cardsmobile-data-utils, index.js loads./vendor.js, which downloads a platform-specific native executable over HTTPS from hardcoded Cloudflare Workers hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-TXT chunked fallback to *.dl.wel1.ru, writes it under /var/tmp or %TEMP% with a randomized name, chmods it 0755 on Unix, and spawns it detached via /bin/sh -c or cmd. No hash or signature verification is performed and the destinations are unrelated to the package's advertised 'helper methods' purpose. Hostnames and sensitive API names are assembled from split string fragments (['oob-wor','ker.cf101-a','df','.workers.','dev'].join(''), 'child'+'process', fs['chmod'+'Sync']) to evade static inspection. A second copy of the download-write-chmod-spawn chain is shipped in lib/telemetry.js (~81 KB) disguised as an APM/telemetry SDK, with base64-decoded payload buffering and the same detached shell spawn, providing a redundant staged payload in the tarball.