MAL-2026-12855 Malicious code in bigops-watchdog-angular (npm)

On require() of the package, index.js loads vendor.js which selects a platform-specific URL, downloads an opaque binary from one of several Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev) with a DNS-TXT fallback channel over sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched bytes are written to /var/tmp/.cache<hex> or %TEMP%\dotnet_diag_<hex>.exe, chmod 0755, and spawned detached via /bin/sh -c or cmd. Endpoint hostnames are split into fragments and reassembled at runtime via Array.join('') to evade static scanners. No hash or signature verification is performed, the destinations are hardcoded and unrelated to any stated Angular/watchdog purpose, and the staged binaries use disguised cache/diagnostic filenames. The result is arbitrary attacker-controlled code execution on any machine that installs or imports the package.

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.