CVE-2021-36851 Explained : Impact and Mitigation

This CVE-2021-36851 involves an Authenticated Cross-Site Scripting (XSS) vulnerability in the Testimonial Slider - Free Testimonials Slider Plugin for WordPress versions less than or equal to 3.5.8.3. The vulnerability was discovered by Ngo Van Thien from Patchstack Alliance.

Understanding CVE-2021-36851

CVE-2021-36851 is a medium severity vulnerability affecting the Web-Settler Testimonial Slider - Free Testimonials Slider Plugin for WordPress versions 3.5.8.3 and below.

What is CVE-2021-36851?

The CVE-2021-36851 vulnerability is an Authenticated Cross-Site Scripting (XSS) security flaw identified in the Web-Settler Testimonial Slider - Free Testimonials Slider Plugin for WordPress. It allows attackers with higher user privileges (editor or above) to inject malicious scripts through specific parameters, posing a risk of unauthorized script execution.

The Impact of CVE-2021-36851

The impact of this vulnerability lies in its potential to manipulate content and compromise the security and integrity of the affected WordPress websites. Attackers exploiting this vulnerability can conduct various malicious activities, including unauthorized data access and potential website defacement.

Technical Details of CVE-2021-36851

The technical details of CVE-2021-36851 are as follows:

Vulnerability Description

The vulnerability allows authenticated attackers with editor or higher user roles to perform Cross-Site Scripting (XSS) attacks by injecting malicious scripts through specific parameters.

Affected Systems and Versions

Web-Settler Testimonial Slider - Free Testimonials Slider Plugin for WordPress versions less than or equal to 3.5.8.3 are affected by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by utilizing parameters such as mpsp_posts_bg_color, mpsp_posts_description_color, and mpsp_slide_nav_button_color to inject malicious scripts.

Mitigation and Prevention

To address CVE-2021-36851 and enhance the security of your WordPress website, consider the following mitigation strategies:

Immediate Steps to Take

Update the Web-Settler Testimonial Slider plugin to a secure version that addresses the XSS vulnerability.
Monitor user roles and permissions to restrict editor or higher privileges unless necessary.

Long-Term Security Practices

Regularly update plugins and themes to patch known vulnerabilities and enhance security.
Implement web application firewalls (WAFs) and security plugins to detect and prevent XSS attacks.

Patching and Updates

Stay informed about security updates released by Web-Settler for the Testimonial Slider plugin and apply patches promptly to mitigate the risk of XSS attacks.