CVE-2020-5809 : Exploit Details and Defense Strategies

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current. An authenticated user can inject arbitrary JavaScript code into iframes when editing content using the TinyMCE rich-text editor.

Understanding CVE-2020-5809

What is CVE-2020-5809?

This CVE refers to a stored Cross-Site Scripting (XSS) vulnerability in Umbraco CMS versions <= 8.9.1 or current, allowing authenticated users to inject malicious JavaScript code into iframes.

The Impact of CVE-2020-5809

The vulnerability enables attackers to execute arbitrary code within the context of the affected site, potentially leading to unauthorized actions or data theft.

Technical Details of CVE-2020-5809

Vulnerability Description

Type: Stored Cross-Site Scripting (XSS)
Affected Product: Umbraco CMS
Affected Versions: <= 8.9.1 or current (unfixed)

Affected Systems and Versions

Umbraco CMS <= 8.9.1 or current (unfixed)

Exploitation Mechanism

Authenticated users can exploit the vulnerability by injecting malicious JavaScript code into iframes while using the TinyMCE rich-text editor in Umbraco CMS.

Mitigation and Prevention

Immediate Steps to Take

Upgrade Umbraco CMS to a fixed version beyond 8.9.1 to mitigate the vulnerability.
Regularly monitor and review user-generated content for suspicious code injections.

Long-Term Security Practices

Implement content security policies to restrict the execution of inline scripts.
Educate users on secure content creation practices to prevent XSS attacks.

Patching and Updates

Stay informed about security updates and promptly apply patches released by Umbraco CMS.