MAL-2026-12703 Malicious code in devplatform-cli-plugin-test (npm)

On require(), runtime.js selects a platform-specific asset, downloads a binary over https.get from hardcoded Cloudflare Workers hosts (with a DNS TXT base64 fallback under dl.wel1.ru), writes it to /var/tmp or %TEMP% under names mimicking diagnostic tools (dotnet_diag.exe,.cache_,.analytics_state), chmods it 0o755, and spawns it detached via spawn('/bin/sh', ['-c', fp+' &'], {detached:true}) or cmd.exe /c start /b. C2 hostnames and fallback domains are reconstructed at runtime from split-string arrays to evade static scanners. No hash or signature verification. The destinations are non-publisher, mutable, and disguised, and the package advertises itself as test fixtures while performing this drop-and-execute on load.