bigops-telephony-client@35.7.6

Analysis

bigops-telephony-client@35.7.6 is a trojanized SDK that, on require, downloads and executes a second-stage binary. It fetches a platform-specific payload over HTTPS from three Cloudflare Workers endpoints (oob-worker[.]cf100-416[.]workers[.]dev, oob-worker[.]cf102-baf[.]workers[.]dev, oob-worker[.]cf103-070[.]workers[.]dev) at paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, or /pkg/package.exe depending on OS/arch. If the HTTP fetch fails it falls back to a DNS-TXT covert channel using the *.dl[.]wel1[.]ru domain family (c[.]sdk[.]dl[.]wel1[.]ru, ext[.]dl[.]wel1[.]ru, pkg[.]dl[.]wel1[.]ru, net[.]dl[.]wel1[.]ru) to retrieve base64-encoded chunks. The downloaded binary is written to a hidden cache file (.cache_<hex> in /var/tmp, or dotnet_diag_<hex>.exe in the Windows TEMP dir) and launched detached via cmd.exe /c start /b on Windows or /bin/sh -c <path> & on Unix, so it runs in the background. The package ships a stub telephony-client class; its actual behaviour is remote binary download-and-execute.