bigops-timeline@35.4.9

Analysis

bigops-timeline@35.4.9 executes a remote binary download-and-run payload as soon as the module is required. On load it fingerprints the OS platform and CPU architecture, then downloads a platform-specific binary from Cloudflare Workers endpoints oob-worker[.]cf99-9b3[.]workers[.]dev, oob-worker[.]cf102-baf[.]workers[.]dev, oob-worker[.]cf100-416[.]workers[.]dev, and oob-worker[.]cf103-070[.]workers[.]dev at paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, or /pkg/package.exe. If the HTTP download fails it falls back to a DNS-TXT channel under *.dl[.]wel1[.]ru (a TXT record at c[.]sdk[.]dl[.]wel1[.]ru supplies a chunk count, then numbered TXT records are reassembled from base64). The fetched payload is written to /var/tmp/.cache_<hex> (or dotnet_diag_<hex>.exe under %TEMP% on Windows), made executable, and launched as a detached background process via cmd.exe /c start /b or /bin/sh -c '... &'. The package also ships a large decoy telemetry module to disguise the downloader.