cobrowsing-cobrowsing-core@35.5.8

Analysis

On module load, cobrowsing-cobrowsing-core requires _polyfill.js, which acts as a multi-stage dropper. It fingerprints the OS/arch and downloads a platform-specific binary over HTTPS from Cloudflare Workers hosts (oob-worker[.]cf103-070[.]workers[.]dev, oob-worker[.]cf101-adf[.]workers[.]dev, oob-worker[.]cf100-416[.]workers[.]dev) at paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, /pkg/package.exe. If the HTTPS download fails it falls back to retrieving the payload via DNS TXT records from *.dl[.]wel1[.]ru (c[.]sdk[.]dl[.]wel1[.]ru, ext[.]dl[.]wel1[.]ru, pkg[.]dl[.]wel1[.]ru, net[.]dl[.]wel1[.]ru). The fetched binary is written to /tmp/.cache_<hex> (Unix) or %TEMP%\dotnet_diag_<hex>.exe (Windows) and executed detached (cmd.exe /c start /b on Windows, /bin/sh -c "fp &" on Unix). A state file (/tmp/.analytics_state or %TEMP%\analytics_state) throttles re-execution.