MAL-2026-12850 Malicious code in bigops-ui-kit-styles (npm)

On require() of bigops-ui-kit-styles, index.js loads compat.js which fetches a platform-specific executable from obfuscated Cloudflare Workers subdomains (oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev) with a DNS TXT fallback under *.dl.wel1.ru. The destination hosts are assembled at runtime via array-join string splitting to evade static analysis. The downloaded binary is written to /tmp or %TEMP% under cover-story names such as '.cache<hex>' and 'dotnet_diag_<hex>.exe', chmod'd 0755, and spawned detached via /bin/sh -c or cmd.exe with.unref(). The exported BigopsUiKitStyles class in index.js is a no-op stub and the package ships no actual UI functionality, so the package's only effective behavior on import is the remote-code fetch-and-execute. Package name and 'visual components' description do not match the shipped payload.

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.