CVE-2020-4049 : Exploit Details and Defense Strategies

In affected versions of WordPress, a vulnerability exists when uploading themes, allowing crafted theme folder names to execute JavaScript in /wp-admin. This self-XSS issue requires admin privileges and has a low severity level. The vulnerability has been patched in version 5.4.2 and previous affected versions.

Understanding CVE-2020-4049

This CVE involves an authenticated self-XSS vulnerability in WordPress related to theme uploads.

What is CVE-2020-4049?

In affected versions of WordPress, a flaw allows malicious theme folder names to trigger JavaScript execution in /wp-admin, requiring admin interaction and resulting in low severity self-XSS.

The Impact of CVE-2020-4049

The vulnerability poses a low severity risk, requiring admin privileges for exploitation, and has been addressed in version 5.4.2 and prior affected versions.

Technical Details of CVE-2020-4049

This section provides detailed technical information about the CVE.

Vulnerability Description

The vulnerability in WordPress allows for JavaScript execution in /wp-admin when uploading themes with specially crafted folder names.

Affected Systems and Versions

WordPress versions >= 5.4.0, < 5.4.2
WordPress versions >= 5.3.0, < 5.3.4
WordPress versions >= 5.2.0, < 5.2.7
WordPress versions >= 5.1.0, < 5.1.6
WordPress versions >= 5.0.0, < 5.0.10
WordPress versions >= 4.9.0, < 4.9.15
WordPress versions >= 4.8.0, < 4.8.14
WordPress versions >= 4.7.0, < 4.7.18
WordPress versions >= 4.6.0, < 4.6.19
WordPress versions >= 4.5.0, < 4.5.22
WordPress versions >= 4.4.0, < 4.4.23
WordPress versions >= 4.3.0, < 4.3.24
WordPress versions >= 4.2.0, < 4.2.28
WordPress versions >= 4.1.0, < 4.1.31
WordPress versions >= 4.0.0, < 4.0.31
WordPress versions >= 3.9.0, < 3.9.32
WordPress versions >= 3.8.0, < 3.8.34
WordPress versions >= 3.7.0, < 3.7.34

Exploitation Mechanism

The vulnerability requires an authenticated admin to upload a theme with a malicious folder name to trigger JavaScript execution.

Mitigation and Prevention

Protect your systems from CVE-2020-4049 with the following measures:

Immediate Steps to Take

Update WordPress to version 5.4.2 or the latest release.
Avoid uploading themes from untrusted sources.
Monitor for any suspicious activities in /wp-admin.

Long-Term Security Practices

Regularly update WordPress and plugins to the latest versions.
Educate users on safe theme and plugin installation practices.

Patching and Updates

Ensure timely installation of security patches and updates provided by WordPress.