MAL-2026-12826 Malicious code in beaver-ui-storybook-addon-code-description (npm)

On require() of the package main, loader.js selects an OS-specific endpoint, downloads a binary via https.get from one of several hardcoded Cloudflare Workers hosts (oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev), writes it to /tmp/.cache<hex> or %TEMP%\dotnet_diag_<hex>.exe, chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start /b. If HTTPS retrieval fails, the loader falls back to a DNS-TXT covert channel: it queries TXT records under *.dl.wel1.ru subdomains (sdk/ext/pkg/net.dl.wel1.ru), concatenates base64 chunks across sequentially-numbered records, decodes, writes, and executes the payload. No hash or signature verification is performed. C2 hostnames are assembled at runtime via array.join("") splits to evade static string matching, and the code is framed with cover-story names (analytics_state, dotnet_diag_, DISABLE_TELEMETRY opt-out) unrelated to the package's declared Storybook-addon purpose. Fetched destinations are unrelated to the publisher's stated purpose, and the payload is attacker-controlled arbitrary code executed on the installer's machine at package load time.

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.