CVE CyberSecurity Database News

CVE-2024-27306: aiohttp XSS Vulnerability on Index Pages and Its Remediation

Poster -

As our online world continues to advance, the need for fast and efficient web applications is always on the rise. One such example is the aiohttp framework, which provides an asynchronous HTTP client/server for asyncio and Python. Recently, a Cross-Site Scripting (XSS) vulnerability was discovered in the index pages of the aiohttp static file handling. This post will delve into the details surrounding the vulnerability, (CVE-2024-27306), and offer solutions, including upgrading to aiohttp 3.9.4.

Vulnerability Details

The XSS vulnerability lies in the index pages that are generated automatically by aiohttp for serving static files. If an attacker is able to create a malicious file with a specially crafted name, the default index page will include that file name, and when it's viewed in a browser, the malicious JavaScript code will be executed.

Here's a code snippet that demonstrates the issue. Let's assume that an attacker has uploaded a file with the name test<script>alert('XSS')</script>.html. When the aiohttp server generates an index page for the static files, it will include this file name, along with the embedded JavaScript:

<!DOCTYPE html>
<html>
<head>
    <title>Index of ./static/</title>
</head>
<body>
    <h1>Index of ./static/</h1>
    <table>
        <tr><td>Name</td><td>Last modified</td></tr>
        <tr>
            <td><a href="test<script>alert('XSS')</script>.html">test<script>alert('XSS')</script>.html</a></td>
            <td>2024-01-01 12:34:56</td>
        </tr>
    </table>
</body>
</html>

Any user who views this index page would now have the malicious JavaScript code executed in their browser, potentially compromising their security.

Affected Versions

aiohttp versions prior to v3.9.4 are affected by this XSS vulnerability.

Original References

The vulnerability was initially reported on aiohttp GitHub Repository, where discussions regarding the issue and its resolution took place.

Remediation and Recommendations

It is strongly recommended to upgrade to aiohttp v3.9.4, where the vulnerability is fixed. Users can upgrade by running the following command:

pip install aiohttp==3.9.4

As a recommended practice, aiohttp's documentation has always advised using a reverse proxy server (e.g. nginx) for serving static files. Users who have followed this recommendation are thus unaffected by the CVE-2024-27306 vulnerability.

For those unable to upgrade, disabling the show_index feature for aiohttp can help mitigate this vulnerability. The show_index feature is enabled by default, and disabling it requires modifying the code that sets up the static file handling, as follows:

file_handler = aiohttp.web.FileResponse("./static", show_index=False)
app.router.add_route("*", "/static/{path:.*}", file_handler)

In conclusion, aiohttp’s recent XSS vulnerability on index pages for static file handling (CVE-2024-27306) demands immediate attention. The best course of action is to upgrade to aiohttp v3.9.4 or follow recommended practices by using a reverse proxy server to serve static files. Alternatively, disabling the show_index feature can also help mitigate the vulnerability for those unable to upgrade. By keeping security practices in check, developers can continue to create fast and efficient web applications using aiohttp while ensuring the safety of their users.

Timeline

Published on: 04/18/2024 15:15:29 UTC
Last modified on: 06/20/2024 13:35:26 UTC