CVE-2021-24253 : Security Advisory and Response

Classyfrieds WordPress plugin version 3.8 and below is vulnerable to an Authenticated Arbitrary File Upload leading to Remote Code Execution (RCE).

Understanding CVE-2021-24253

This CVE involves the Classyfrieds WordPress plugin that allows authenticated users to upload arbitrary PHP files leading to RCE.

What is CVE-2021-24253?

The Classyfrieds WordPress plugin through version 3.8 lacks proper validation on uploaded files, enabling authenticated users to upload malicious PHP files via the Add Listing feature, potentially leading to RCE.

The Impact of CVE-2021-24253

This vulnerability can be exploited by authenticated users to compromise the WordPress site hosting the vulnerable plugin, allowing unauthorized execution of arbitrary PHP code.

Technical Details of CVE-2021-24253

The technical details of this CVE include:

Vulnerability Description

The vulnerability arises from the plugin not adequately examining uploaded files, allowing authenticated users to upload PHP files.

Affected Systems and Versions

Classyfrieds plugin versions up to and including 3.8 are impacted by this vulnerability.

Exploitation Mechanism

By leveraging the Add Listing feature, authenticated users can manipulate the file upload process to insert malicious PHP files, potentially achieving RCE.

Mitigation and Prevention

To address CVE-2021-24253, consider the following steps:

Immediate Steps to Take

Disable the Classyfrieds plugin if not essential
Update the plugin to the latest secure version

Long-Term Security Practices

Ensure file upload validations are stringent for user inputs and regularly monitor for security updates and patches.

Patching and Updates

Regularly check for plugin updates and apply them promptly to safeguard against known vulnerabilities.