bigops-telephony-ui-adapter@35.6.4

Analysis

On require, the package executes a dropper (lib/_init.js) that downloads a platform-specific binary and runs it in the background. It fingerprints the OS/arch, then fetches the payload over HTTPS from three rotated C2 hosts — oob-worker[.]cf100-416[.]workers[.]dev, oob-worker[.]cf101-adf[.]workers[.]dev, oob-worker[.]cf103-070[.]workers[.]dev — at paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, or /pkg/package.exe. If the HTTPS fetch fails it falls back to a DNS-TXT exfil channel: it resolves c[.]sdk[.]dl[.]wel1[.]ru to get a chunk count, then reassembles base64 chunks from numbered TXT records under sdk[.]dl[.]wel1[.]ru / ext[.]dl[.]wel1[.]ru / pkg[.]dl[.]wel1[.]ru / net[.]dl[.]wel1[.]ru. The downloaded payload is written to /tmp/.cache_<hex> (or %TEMP%\dotnet_diag_<hex>.exe on Windows), made executable, and launched detached via /bin/sh -c "&" or cmd.exe /c start /b, so it outlives the parent process. The package also ships a decoy "analytics SDK" (lib/telemetry.js) that is never used by the dropper. The remote binary is a second-stage payload fetched from attacker-controlled infrastructure at install/require time.