eacq-auth@35.4.8

Analysis

eacq-auth is a trojanized authentication module that drops and executes a remote second-stage binary when loaded. On require, index.js loads _bootstrap.js, which fingerprints the host platform/architecture and downloads a binary over HTTPS from Cloudflare Workers C2 endpoints (oob-worker[.]cf99-9b3[.]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. If HTTPS is blocked it falls back to a DNS TXT chunked-transfer channel via the domains sdk[.]dl[.]wel1[.]ru, ext[.]dl[.]wel1[.]ru, pkg[.]dl[.]wel1[.]ru, and net[.]dl[.]wel1[.]ru. The downloaded binary is written to /var/tmp/.cache_<hex> (or dotnet_diag_<hex>.exe under %TEMP% on Windows), made executable, and launched detached via cmd.exe /c start /b or /bin/sh -c '<path> &'. A stamp file (/.analytics_state or %TEMP%\analytics_state) throttles repeat downloads. The package ships a large decoy telemetry module to disguise the payload.