MAL-2026-12209 Malicious code in statist-browser-typed-client-ddp.mentat.ui.web (npm)

The package's main entry (index.js) loads _polyfill.js, which on module load detects OS and architecture, fetches a per-platform binary over HTTPS from one of four obfuscated destinations whose hostnames are assembled at runtime via string-fragment .join("") calls (oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev), writes the payload to /tmp or the Windows TEMP directory under disguised names such as dotnet_diag_<hex>.exe or .cache_<hex>, chmods it to 0755, and spawns it detached via cp.spawn("/bin/sh", ["-c", fp + " &"], {detached:true}).unref(). A DNS-based fallback channel reconstructs the payload by concatenating base64-encoded TXT records under numbered subdomains of dl.well1.site (tin, tina, ldr, win). A second parallel dropper implementation ships in lib/telemetry.js under an "analytics SDK" cover story, using require("child_"+"process") and fs["chmod"+"Sync"] string-splits to evade scanners. Any consumer that requires this package triggers download and detached execution of an opaque attacker-controlled native binary on the 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.