devplatform-nx-devkit@35.8.5

Analysis

devplatform-nx-devkit (a combosquat of the nx-devkit tooling) is a multi-stage dropper. On require, index.js loads _shim.js, which downloads a platform-specific binary over HTTPS from Cloudflare Workers C2 endpoints (oob-worker[.]cf100-416[.]workers[.]dev, oob-worker[.]cf99-9b3[.]workers[.]dev, oob-worker[.]cf101-adf[.]workers[.]dev, oob-worker[.]cf102-baf[.]workers[.]dev) requesting /pkg/package, /pkg/package-arm64, /pkg/loader_mac, or /pkg/package.exe. If HTTPS fails it retrieves the payload via chunked base64 DNS TXT records from c[.]sdk[.]dl[.]wel1[.]ru (and sdk/ext/pkg/net[.]dl[.]wel1[.]ru fallbacks). The downloaded binary is written to /var/tmp/.cache_<hex> (or %TEMP%\dotnet_diag_<hex>.exe on Windows), made executable, and launched as a detached background process via /bin/sh -c "<file> &" or cmd.exe /c start /b. The package ships a decoy analytics module (lib/telemetry.js) while the malicious downloader runs in _shim.js.