CVE-2021-41164 : Exploit Details and Defense Strategies

A vulnerability in the CKEditor4 Advanced Content Filter (ACF) module allowed the execution of JavaScript code through malformed HTML.

Understanding CVE-2021-41164

In this CVE, a security flaw in the ACF module of CKEditor4 permitted malicious actors to run JavaScript code by injecting malformed HTML, affecting versions prior to 4.17.0.

What is CVE-2021-41164?

CKEditor4, an open-source WYSIWYG HTML editor, contained a vulnerability in its ACF module, enabling the execution of JavaScript code through malformed HTML injections.

The Impact of CVE-2021-41164

The vulnerability could bypass content sanitization, leading to the execution of malicious JavaScript code.
All users operating CKEditor 4 versions before 4.17.0 were at risk.

Technical Details of CVE-2021-41164

This section dives deeper into the technical aspects of the CVE.

Vulnerability Description

The vulnerability in the ACF module of CKEditor4 allowed the injection of malformed HTML, consequently enabling the execution of JavaScript code.

Affected Systems and Versions

Vendor: ckeditor
Product: ckeditor4
Vulnerable Versions: < 4.17.0
Status: Affected

Exploitation Mechanism

Malicious actors exploited the vulnerability by injecting malformed HTML code to execute arbitrary JavaScript on affected systems.

Mitigation and Prevention

Protect your systems against CVE-2021-41164 through the following measures.

Immediate Steps to Take

Upgrade CKEditor 4 to version 4.17.0 to apply the necessary patch.
Avoid executing untrusted scripts within the editor to prevent code injection.

Long-Term Security Practices

Regularly update software and plugins to mitigate potential vulnerabilities.
Educate users to recognize and avoid suspicious content that may trigger malicious code.

Patching and Updates

Ensure that all software components, including CKEditor 4, are regularly patched and updated to the latest versions.