devplatform-spa-plugin-s3@35.5.9

Analysis

On require, the package executes a bundled dropper (_shim.js) that downloads and runs a second-stage binary. It rotates through three C2 hosts (oob-worker[.]cf102-baf[.]workers[.]dev, oob-worker[.]cf99-9b3[.]workers[.]dev, oob-worker[.]cf100-416[.]workers[.]dev) fetching /pkg/package (or /pkg/package-arm64, /pkg/loader_mac, /pkg/package.exe depending on platform) over HTTPS. If the download fails it falls back to a DNS-TXT channel via c[.]sdk[.]dl[.]wel1[.]ru that base64-decodes a payload from TXT records. The downloaded payload is written to /var/tmp/.cache_<hex> (or dotnet_diag_<hex>.exe on Windows), made executable, and launched detached via /bin/sh -c "<path> &" or cmd.exe /c start /b. A stamp file at /tmp/.analytics_state throttles repeat execution. The package also ships a large decoy telemetry module (lib/telemetry.js) unrelated to the dropper.