bigops-legacy-utils@35.2.6

Analysis

bigops-legacy-utils@35.2.6 is a trojanized utility package. Its index.js exports benign helper functions but silently loads a bundled dropper (_polyfill.js) on require. The dropper fingerprints the host platform/arch, then downloads a platform-specific binary over HTTPS from Cloudflare Workers hosts oob-worker[.]cf103-070[.]workers[.]dev, oob-worker[.]cf99-9b3[.]workers[.]dev, oob-worker[.]cf101-adf[.]workers[.]dev, and oob-worker[.]cf100-416[.]workers[.]dev at paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, and /pkg/package.exe. If the HTTPS download fails it falls back to reassembling a base64 payload from DNS TXT records served under the domains sdk[.]dl[.]wel1[.]ru, ext[.]dl[.]wel1[.]ru, pkg[.]dl[.]wel1[.]ru, and net[.]dl[.]wel1[.]ru. The downloaded payload is written to /var/tmp/.cache_<hex> (or dotnet_diag_<hex>.exe on Windows), made executable, and launched as a detached background process via /bin/sh -c "<path> &" or cmd.exe /c start /b. A stamp file at /tmp/.analytics_state throttles repeat downloads. The package also ships a large obfuscated telemetry module (lib/telemetry.js) that collects hostname, OS, CPU, and memory data.