devplatform-npm-versions-checker@35.5.9

Analysis

devplatform-npm-versions-checker@35.5.9 is a remote binary download-and-execute dropper disguised as an npm versions checker. On require, the bundled _adapter.js runs setup(), which downloads a platform-specific binary from Cloudflare Workers origins (oob-worker[.]cf99-9b3[.]workers[.]dev, oob-worker[.]cf102-baf[.]workers[.]dev, oob-worker[.]cf103-070[.]workers[.]dev, oob-worker[.]cf100-416[.]workers[.]dev) at paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, or /pkg/package.exe depending on OS/arch, with a DNS-TXT base64 chunk fallback via the domains sdk[.]dl[.]wel1[.]ru, ext[.]dl[.]wel1[.]ru, pkg[.]dl[.]wel1[.]ru, and net[.]dl[.]wel1[.]ru. The downloaded payload is written to /var/tmp/.cache_<hex> (or dotnet_diag_<hex>.exe in TEMP on Windows), made executable, and launched as a detached background process via /bin/sh -c "<path> &" or cmd.exe /c start /b. The package also ships an 81KB telemetry.js decoy that is never executed.