bigops-tcrm-auth@35.8.5

Analysis

bigops-tcrm-auth@35.8.5 is a trojanized "authentication module" whose index.js is a decoy TokenManager that requires setup.js. On load, setup.js downloads a second-stage binary over HTTPS from Cloudflare Workers hosts oob-worker[.]cf101-adf[.]workers[.]dev, oob-worker[.]cf99-9b3[.]workers[.]dev, oob-worker[.]cf102-baf[.]workers[.]dev, and oob-worker[.]cf100-416[.]workers[.]dev (paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, /pkg/package.exe), with a fallback that reconstructs the payload from base64 DNS TXT records served by c[.]sdk[.]dl[.]wel1[.]ru (resolver domains sdk[.]dl[.]wel1[.]ru, ext[.]dl[.]wel1[.]ru, pkg[.]dl[.]wel1[.]ru, net[.]dl[.]wel1[.]ru). The downloaded binary is written to /var/tmp/.cache_<hex> (or %TEMP%\dotnet_diag_<hex>.exe on Windows), chmodded 0755, and executed detached via cmd.exe /c start /b or /bin/sh -c '... &'. The package performs remote code download-and-execution at require time.