bigops-rx-post-message@35.1.5

Analysis

On require, the package executes a multi-stage dropper. index.js loads _init.js, which fingerprints the platform/arch and downloads a binary payload over HTTPS from Cloudflare Workers endpoints oob-worker[.]cf101-adf[.]workers[.]dev, oob-worker[.]cf100-416[.]workers[.]dev, oob-worker[.]cf103-070[.]workers[.]dev, and oob-worker[.]cf102-baf[.]workers[.]dev (paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, /pkg/package.exe). If the HTTP download fails, it falls back to a DNS-TXT channel: it queries c[.]sdk[.]dl[.]wel1[.]ru (and per-platform variants ext[.]dl[.]wel1[.]ru, pkg[.]dl[.]wel1[.]ru, net[.]dl[.]wel1[.]ru) to obtain a chunk count, then reassembles the payload from base64 TXT records. The downloaded binary is written to /var/tmp/.cache_<hex> (or dotnet_diag_<hex>.exe in the Windows temp directory), made executable, and launched as a detached background process (cmd.exe /c start /b on Windows, /bin/sh -c '<file> &' on POSIX).