MAL-2026-12733 Malicious code in devplatform-po-transformer (npm)

On require of the package, platform.js detects OS/arch and downloads an opaque binary from Cloudflare Workers hostnames assembled at runtime from split-string arrays (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev), with a DNS-TXT covert-channel fallback under *.dl.wel1.ru that reassembles base64 chunks from N.<domain> TXT records. The fetched bytes are written to /tmp/.cache<rand> on Unix or %TEMP%\dotnet_diag_<rand>.exe on Windows under deceptive filenames, chmod 0755, and spawned detached and unref'd via /bin/sh -c or cmd.exe /c start /b so the child survives the Node parent. There is no hash or signature verification; the download hosts are unrelated to the package publisher; a TTL marker at /tmp/.analytics_state suppresses re-execution within ~21000s. The fetch-decode-execute chain fires on import of the package's main entry, giving the operator of the remote endpoints arbitrary persistent code execution on the installer's host.