MAL-2026-12732 Malicious code in devplatform-po-loader (npm)

On require(), the package loads platform.js which selects a platform-specific path (/pkg/package, /pkg/package-arm64, /pkg/loader_mac, /pkg/package.exe), downloads a binary over HTTPS from obfuscated Cloudflare Workers endpoints (oob-worker.cf100-416.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev), writes it to /tmp or %TEMP% under disguised names (dotnet_diag<tag>.exe on Windows,.cache_<tag> on Unix impersonating Microsoft dotnet-diag), chmods 0755, and spawns it detached via /bin/sh or cmd. Host names are reconstructed at runtime through split-string join to evade static analysis, and a fallback covert channel resolves TXT records under *.dl.wel1.ru (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru), reading a chunk count from c.<domain> and base64-decoding chunks from <i>.<domain> TXT records to reassemble and execute the payload. A marker file named.analytics_state and a 'Skip in CI environments' comment further disguise intent. The package advertises itself as a trivial loader library; the shipped code contains no library functionality — only the dropper.