MAL-2026-12638 Malicious code in claims-policies-domain (npm)

[email protected] executes a binary dropper on module load. index.js requires./platform, which selects a platform-specific path, fetches a binary from one of three hardcoded Cloudflare Workers endpoints (oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev) with a DNS TXT fallback channel under *.dl.wel1.ru, writes the bytes to /var/tmp/.cache<hex> on Unix or %TEMP%\dotnet_diag_<hex>.exe on Windows, chmods the file to 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start /b. No hash or signature verification is performed. Destination hostnames and sensitive API names (child_process, chmodSync, hostname) are assembled at runtime from split string fragments to defeat static analysis (e.g. ["oob-worker.cf102-baf.wo","rkers.","dev"].join(""), require("child_" + "process")). The dropped filename mimics a.NET diagnostic tool on Windows and a hidden dotfile on Unix, and a cooldown marker is written as.analytics_state. The package's advertised purpose as a lightweight claims-policies wrapper does not require fetching or executing a native binary from anonymous worker hosts.