CVE-2021-24556 Explained : Impact and Mitigation

A Stored Cross-Site Scripting (XSS) vulnerability has been discovered in the Email Subscriber WordPress plugin version 1.1 or below, allowing attackers to execute malicious scripts on vulnerable websites.

Understanding CVE-2021-24556

This CVE identifies a security issue in the Email Subscriber plugin that could be exploited by attackers to inject and execute arbitrary scripts on the target site.

What is CVE-2021-24556?

The vulnerability exists in the way the plugin handles input parameters, specifically 'subscribe_email' and 'subscribe_name', which are not properly sanitized before being stored in the database and displayed back to users. This can lead to a Stored XSS attack.

The Impact of CVE-2021-24556

Exploitation of this vulnerability can result in unauthorized access to sensitive data, defacement of websites, or the unauthorized execution of actions on behalf of the user, posing a significant security risk to affected websites.

Technical Details of CVE-2021-24556

This section provides more detailed information about the vulnerability.

Vulnerability Description

The issue lies in the 'kento_email_subscriber_ajax' action of the plugin, where input parameters are not properly sanitized, validated, and escaped before being processed, leading to the execution of malicious scripts.

Affected Systems and Versions

The vulnerability affects Email Subscriber plugin version 1.1 and prior.

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting malicious input values for 'subscribe_email' and 'subscribe_name' parameters, leading to the execution of unauthorized scripts.

Mitigation and Prevention

To address CVE-2021-24556 and enhance the security of your WordPress site, follow these guidelines:

Immediate Steps to Take

Update the Email Subscriber plugin to the latest version to patch the vulnerability.
Monitor the plugin vendor's website for any security advisories and apply patches promptly.

Long-Term Security Practices

Implement input validation and output encoding to prevent XSS attacks.
Regularly audit and review third-party plugins for security vulnerabilities.

Patching and Updates

Always keep your WordPress plugins, themes, and core files updated to mitigate known security risks.