MAL-2026-12856 Malicious code in bigops-watchdog-worker (npm)

On require() of bigops-watchdog-worker, index.js loads runtime.js which reconstructs remote hostnames from split-string fragments (e.g. joining ["oob-w","orker.cf102-baf.workers.d","ev"] and ['sdk.dl.wel1','.ru']), selects a URL keyed on process.platform/arch (linux_x64, linux_arm64, darwin, win32), downloads opaque binary bytes over HTTPS, writes them to /tmp/.cache<uid> on Unix or %TEMP%\dotnet_diag_<uid>.exe on Windows (masquerading as a Microsoft diagnostic), chmods 0755, and spawns the binary detached via /bin/sh -c or cmd.exe. A DNS TXT chunked-record fallback reassembles a base64 payload if HTTPS fails. Anti-analysis features include a cache stamp at /tmp/.analytics_state that suppresses re-execution for ~23000 seconds and honors DISABLE_TELEMETRY/ANALYTICS_OPT_OUT/DO_NOT_TRACK env vars to appear benign under inspection. Neither oob-worker.*.workers.dev nor *.dl.wel1.ru is a publisher-controlled or publisher-adjacent host.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.