CVE-2023-49279 : Exploit Details and Defense Strategies
Learn about CVE-2023-49279 affecting Umbraco CMS versions prior to 7.15.11, 8.18.9, 10.7.0, 11.5.0, and 12.2.0. Find out the impact, technical details, and mitigation steps.
Umbraco CMS vulnerable to stored XSS via SVG File Upload
Understanding CVE-2023-49279
Umbraco CMS versions prior to 7.15.11, 8.18.9, 10.7.0, 11.5.0, and 12.2.0 are vulnerable to stored Cross-Site Scripting (XSS) via SVG file uploads.
What is CVE-2023-49279?
Umbraco, an ASP.NET content management system, allows users to upload SVG files that may contain scripts. If a user can persuade another user to load such media directly in a browser, the scripts can be executed, leading to a stored XSS vulnerability.
The Impact of CVE-2023-49279
The vulnerability in Umbraco CMS could allow an attacker to execute malicious scripts within the context of a user's session, potentially leading to unauthorized actions or data theft.
Technical Details of CVE-2023-49279
Vulnerability Description
The vulnerability (CVE-2023-49279) arises from improper neutralization of user input during web page generation, allowing for stored XSS attacks via SVG file uploads.
Affected Systems and Versions
Umbraco-CMS versions >= 7.0.0 and < 7.15.11, >= 8.0.0 and < 8.18.9, >= 9.0.0-rc001 and < 10.7.0, >= 11.0.0-rc1 and < 11.5.0, >= 12.0.0-rc1 and < 12.2.0 are impacted by this vulnerability.
Exploitation Mechanism
Users with access to the backoffice can upload SVG files containing scripts, subsequently tricking other users into loading the media directly in a browser to execute the scripts.
Mitigation and Prevention
Immediate Steps to Take
- Update Umbraco CMS to versions 7.15.11, 8.18.9, 10.7.0, 11.5.0, or 12.2.0 containing the patch for this vulnerability.
- Implement server-side file validation to prevent malicious uploads.
Long-Term Security Practices
- Regularly educate users on safe file upload practices to mitigate the risk of XSS vulnerabilities.
- Consider serving media from a different host (e.g., a CDN) to isolate content from potentially vulnerable systems.
Patching and Updates
Ensure timely patching and updates for Umbraco-CMS to address security vulnerabilities and protect against potential exploits.