MAL-2026-12748 Malicious code in devplatform-s3-resources (npm)

On load, index.js unconditionally requires./compat.js, which selects a platform-specific binary URL from string-split-obfuscated Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, cf103-070.workers.dev, cf102-baf.workers.dev), downloads the binary over HTTPS with a DNS-TXT covert-channel fallback that reassembles base64 chunks from TXT records under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, writes it to /var/tmp or %TEMP% under masquerading names (.cache<hex> on Unix, dotnet_diag_<hex>.exe on Windows), chmods it 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start /b with stdio ignored and windowsHide set. A stamp file at /tmp/.analytics_state (or %TEMP%\analytics_state) with a ~5.9h MAX_AGE dedupes re-executions across sessions. Endpoint hostnames are constructed by joining split string literals to evade static scanners, and CI opt-out checks are present to reduce detection in build environments. The package name resembles legitimate S3 tooling but the shipped code is a second-stage loader, not an S3 resource library.