chore(deps): update dependency astro to v4.16.18 [security] #40

renovate · 2024-10-14T20:20:05Z

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
astro (source)	`4.3.1` -> `4.16.18`

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.

CVE-2024-56159

Summary

A bug in the build process allows any unauthenticated user to read parts of the server source code.

Details

During build, along with client assets such as css and font files, the sourcemap files for the server code are moved to a publicly-accessible folder.
https://github.com/withastro/astro/blob/176fe9f113fd912f9b61e848b00bbcfecd6d5c2c/packages/astro/src/core/build/static-build.ts#L139

Any outside party can read them with an unauthorized HTTP GET request to the same server hosting the rest of the website.

While some server files are hashed, making their access obscure, the files corresponding to the file system router (those in src/pages) are predictably named. For example. the sourcemap file for src/pages/index.astro gets named dist/client/pages/index.astro.mjs.map.

PoC

Here is one example of an affected open-source website:
https://creatorsgarten.org/pages/index.astro.mjs.map

The file can be saved and opened using https://evanw.github.io/source-map-visualization/ to reconstruct the source code.

The above accurately mirrors the source code as seen in the repository: https://github.com/creatorsgarten/creatorsgarten.org/blob/main/src/pages/index.astro

The above was found as the 4th result (and the first one on Astro 5.0+) when making the following search query on GitHub.com (search results link):

path:astro.config.mjs @&#8203;sentry/astro

This vulnerability is the root cause of https://github.com/withastro/astro/issues/12703, which links to a simple stackblitz project demonstrating the vulnerability. Upon build, notice the contents of the dist/client (referred to as config.build.client in astro code) folder. All astro servers make the folder in question accessible to the public internet without any authentication. It contains .map files corresponding to the code that runs on the server.

Impact

All server-output (SSR) projects on Astro 5 versions v5.0.3 through v5.0.6 (inclusive), that have sourcemaps enabled, either directly or through an add-on such as sentry, are affected. The fix for server-output projects was released in [email protected].

Additionally, all static-output (SSG) projects built using Astro 4 versions 4.16.17 or older, or Astro 5 versions 5.0.7 or older, that have sourcemaps enabled are also affected. The fix for static-output projects was released in [email protected], and backported to Astro v4 in [email protected].

The immediate impact is limited to source code. Any secrets or environment variables are not exposed unless they are present verbatim in the source code.

There is no immediate loss of integrity within the the vulnerable server. However, it is possible to subsequently discover another vulnerability via the revealed source code .

There is no immediate impact to availability of the vulnerable server. However, the presence of an unsafe regular expression, for example, can quickly be exploited to subsequently compromise the availability.

Network attack vector.
Low attack complexity.
No privileges required.
No interaction required from an authorized user.
Scope is limited to first party. Although the source code of closed-source third-party software may also be exposed.

Remediation

The fix for server-output projects was released in [email protected], and the fix for static-output projects was released in [email protected] and backported to Astro v4 in [email protected]. Users are advised to update immediately if they are using sourcemaps or an integration that enables sourcemaps.

Release Notes

withastro/astro (astro)

chore(deps): update dependency astro to v4.16.18 [security] #40

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chore(deps): update dependency astro to v4.16.18 [security] #40

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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Details

PoC

Impact

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Configuration

cloudflare-workers-and-pages bot commented Oct 14, 2024 • edited Loading

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renovate bot commented Oct 14, 2024 •

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

Pattern 2: Request without `Content-Type` header

cloudflare-workers-and-pages bot commented Oct 14, 2024 •

edited

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