fix(deps): update dependency astro to v4.16.17 [security] #521

renovate-bot · 2024-10-14T22:09:17Z

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
astro (source)	`4.4.15` -> `4.16.17`

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GitHub Vulnerability Alerts

CVE-2024-47885

Summary

A DOM Clobbering gadget has been discoverd in Astro's client-side router. It can lead to cross-site scripting (XSS) in websites enables Astro's client-side routing and has stored attacker-controlled scriptless HTML elements (i.e., iframe tags with unsanitized name attributes) on the destination pages.

Details

Backgrounds

DOM Clobbering is a type of code-reuse attack where the attacker first embeds a piece of non-script, seemingly benign HTML markups in the webpage (e.g. through a post or comment) and leverages the gadgets (pieces of js code) living in the existing javascript code to transform it into executable code. More for information about DOM Clobbering, here are some references:

[1] https://scnps.co/papers/sp23_domclob.pdf
[2] https://research.securitum.com/xss-in-amp4email-dom-clobbering/

Gadgets found in Astro

We identified a DOM Clobbering gadget in Astro's client-side routing module, specifically in the <ViewTransitions /> component. When integrated, this component introduces the following vulnerable code, which is executed during page transitions (e.g., clicking an <a> link):

https://github.com/withastro/astro/blob/7814a6cad15f06931f963580176d9b38aa7819f2/packages/astro/src/transitions/router.ts#L135-L156

However, this implementation is vulnerable to a DOM Clobbering attack. The document.scripts lookup can be shadowed by an attacker injected non-script HTML elements (e.g., <img name="scripts"><img name="scripts">) via the browser's named DOM access mechanism. This manipulation allows an attacker to replace the intended script elements with an array of attacker-controlled scriptless HTML elements.

The condition script.dataset.astroExec === '' on line 138 can be bypassed because the attacker-controlled element does not have a data-astroExec attribute. Similarly, the check on line 134 can be bypassed as the element does not require a type attribute.

Finally, the innerHTML of an attacker-injected non-script HTML elements, which is plain text content before, will be set to the .innerHTML of an script element that leads to XSS.

PoC

Consider a web application using Astro as the framework with client-side routing enabled and allowing users to embed certain scriptless HTML elements (e.g., form or iframe). This can be done through a bunch of website's feature that allows users to embed certain script-less HTML (e.g., markdown renderers, web email clients, forums) or via an HTML injection vulnerability in third-party JavaScript loaded on the page.

For PoC website, please refer to: https://stackblitz.com/edit/github-4xgj2d. Clicking the "about" button in the menu will trigger an alert(1) from an attacker-injected form element.

---
import Header from "../components/Header.astro";
import Footer from "../components/Footer.astro";
import { ViewTransitions } from "astro:transitions";
import "../styles/global.css";
const { pageTitle } = Astro.props;
---
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
    <meta name="viewport" content="width=device-width" />
    <meta name="generator" content={Astro.generator} />
    <title>{pageTitle}</title>
    <ViewTransitions />
  </head>
  <body>
    <!--USER INPUT-->
    <iframe name="scripts">alert(1)</iframe>
    <iframe name="scripts">alert(1)</iframe>
    <!--USER INPUT-->
    
    <Header />
    <h1>{pageTitle}</h1>
    <slot />
    <Footer />
    <script>
      import "../scripts/menu.js";
    </script>
  </body>
</html>

Impact

This vulnerability can result in cross-site scripting (XSS) attacks on websites that built with Astro that enable the client-side routing with ViewTransitions and store the user-inserted scriptless HTML tags without properly sanitizing the name attributes on the page.

Patch

We recommend replacing document.scripts with document.getElementsByTagName('script') for referring to script elements. This will mitigate the possibility of DOM Clobbering attacks leveraging the name attribute.

Reference

Similar issues for reference:

Webpack (CVE-2024-43788)
Vite (CVE-2024-45812)
layui (CVE-2024-47075)

CVE-2024-56140

Summary

A bug in Astro’s CSRF-protection middleware allows requests to bypass CSRF checks.

Details

When the security.checkOrigin configuration option is set to true, Astro middleware will perform a CSRF check. (Source code: https://github.com/withastro/astro/blob/6031962ab5f56457de986eb82bd24807e926ba1b/packages/astro/src/core/app/middlewares.ts)

For example, with the following Astro configuration:

// astro.config.mjs
import { defineConfig } from 'astro/config';
import node from '@&#8203;astrojs/node';

export default defineConfig({
	output: 'server',
	security: { checkOrigin: true },
	adapter: node({ mode: 'standalone' }),
});

A request like the following would be blocked if made from a different origin:

// fetch API or <form action="https://test.example.com/" method="POST">
fetch('https://test.example.com/', {
	method: 'POST',
	credentials: 'include',
	body: 'a=b',
	headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
});
// => Cross-site POST form submissions are forbidden

However, a vulnerability exists that can bypass this security.

Pattern 1: Requests with a semicolon after the `Content-Type`

A semicolon-delimited parameter is allowed after the type in Content-Type.

Web browsers will treat a Content-Type such as application/x-www-form-urlencoded; abc as a simple request and will not perform preflight validation. In this case, CSRF is not blocked as expected.

fetch('https://test.example.com', {
	method: 'POST',
	credentials: 'include',
	body: 'test',
	headers: { 'Content-Type': 'application/x-www-form-urlencoded; abc' },
});
// => Server-side functions are executed (Response Code 200).

Pattern 2: Request without `Content-Type` header

The Content-Type header is not required for a request. The following examples are sent without a Content-Type header, resulting in CSRF.

// Pattern 2.1 Request without body
fetch('http://test.example.com', { method: 'POST', credentials: 'include' });

// Pattern 2.2 Blob object without type
fetch('https://test.example.com', {
	method: 'POST',
	credentials: 'include',
	body: new Blob(['a=b'], {}),
});

Impact

Bypass CSRF protection implemented with CSRF middleware.

Note

Even with credentials: 'include', browsers may not send cookies due to third-party cookie blocking. This feature depends on the browser version and settings, and is for privacy protection, not as a CSRF measure.

Release Notes

withastro/astro (astro)

fix(deps): update dependency astro to v4.16.17 [security] #521

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fix(deps): update dependency astro to v4.16.17 [security] #521

Conversation

renovate-bot commented Oct 14, 2024 • edited Loading

GitHub Vulnerability Alerts

Summary

Details

Backgrounds

Gadgets found in Astro

PoC

Impact

Patch

Reference

Summary

Details

Pattern 1: Requests with a semicolon after the Content-Type

Pattern 2: Request without Content-Type header

Impact

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Configuration

renovate-bot commented Oct 14, 2024 •

edited

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Pattern 1: Requests with a semicolon after the `Content-Type`

Pattern 2: Request without `Content-Type` header