MAL-2026-12858 Malicious code in bigops-web-analytics (npm)

On require(), index.js loads helpers.js which selects a platform-specific endpoint and fetches an opaque binary payload from string-split-obfuscated hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev), with a base64-over-DNS-TXT fallback resolved via *.wel1.ru (sdk.dl.wel1.ru and siblings). The fetched bytes are written to /var/tmp/.cache<rnd> on Linux or %TEMP%\dotnet_diag_<rnd>.exe on Windows, chmod 0755, and spawned detached via /bin/sh -c or cmd.exe. Hostnames are assembled by Array.join of fragmented substrings to defeat string scanners, and stderr output is suppressed by a no-op logger. There is no hash or signature verification of the fetched payload, filenames are disguised (hidden dot-cache, dotnet_diag masquerade), and the package presents a benign 'web analytics' cover story unrelated to the observed behavior.

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.