MAL-2026-12046 Malicious code in statist-browser-typed-client-test.jumpwork.circuitbreaker (npm)

On require() of the package's main entry, _compat.js runs as a side effect: it selects a per-platform payload, fetches a native binary over HTTPS from one of several Cloudflare Workers hosts whose names are reconstructed at runtime by joining small string fragments (e.g. oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev), writes it to /tmp/.cache_<hex> on Unix or %TEMP%\dotnet_diag_<hex>.exe on Windows, chmods it 0755, and spawns it detached via /bin/sh -c "<file> &" or cmd /c start /b. A DNS-TXT covert channel provides a fallback delivery path against *.dl.well1.site (tin/tina/ldr/win subdomains), retrieving a count record at c.<domain> and then base64-encoded chunks from <i>.<domain> that are concatenated and executed. A second, larger duplicate of the same dropper (dynamic child_"+"process require, chmod-plus-detached-spawn, DNS discovery, base64 buffer assembly) is shipped as lib/telemetry.js in the tarball. Hostname string-array obfuscation and decoy filenames (dotfile cache, dotnet_diag_*.exe) indicate intentional evasion; installing or importing this package executes attacker-controlled native code on the developer's machine.

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.