CVE-2021-24134 : Exploit Details and Defense Strategies

Constant Contact Forms plugin for WordPress before version 1.8.8 is vulnerable to multiple Stored Cross-Site Scripting (XSS) attacks, enabling high-privileged users to inject malicious scripts or HTML into posts.

Understanding CVE-2021-24134

This CVE identifies the security issue in the Constant Contact Forms WordPress plugin that allows attackers to execute Stored XSS attacks.

What is CVE-2021-24134?

The CVE-2021-24134 vulnerability arises from unvalidated input and lack of output encoding in the Constant Contact Forms plugin, versions prior to 1.8.8. It permits authenticated users with high privileges to insert arbitrary JavaScript code or HTML into posts containing the compromised form.

The Impact of CVE-2021-24134

Exploitation of this vulnerability can result in unauthorized JavaScript execution within the context of a victim's session, potentially leading to data theft, privilege escalation, or site defacement.

Technical Details of CVE-2021-24134

This section outlines specific details related to the vulnerability.

Vulnerability Description

The issue is attributed to unsanitized data inputs in the Constant Contact Forms plugin, allowing attackers to embed harmful scripts within posts.

Affected Systems and Versions

Constant Contact Forms plugin versions prior to 1.8.8 are vulnerable to this exploit.

Exploitation Mechanism

Attackers with Editor+ privileges can abuse the lack of input validation to insert malicious scripts or HTML code into posts, which can be triggered when the infected form is viewed.

Mitigation and Prevention

Protecting your WordPress site from CVE-2021-24134 involves immediate actions and long-term security measures.

Immediate Steps to Take

Update the Constant Contact Forms plugin to version 1.8.8 or later.
Audit posts and remove any suspicious content injected through forms.

Long-Term Security Practices

Implement secure coding practices to validate and sanitize user inputs.
Regularly update plugins and WordPress core to patch vulnerabilities.

Patching and Updates

Stay informed about security updates for plugins and WordPress to promptly address any known vulnerabilities.