CVE-2024-3564 in Content Blocks Plugin
Summary
by MITRE • 06/01/2024
The Content Blocks (Custom Post Widget) plugin for WordPress is vulnerable to Local File Inclusion in all versions up to, and including, 3.3.0 via the plugin's 'content_block' shortcode. This makes it possible for authenticated attackers, with contributor-level access and above, to include and execute arbitrary files on the server, allowing the execution of any PHP code in those files. This can be used to bypass access controls, obtain sensitive data, or achieve code execution in cases where images and other “safe” file types can be uploaded and included.
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Analysis
by VulDB Data Team • 06/03/2024
The vulnerability identified as CVE-2024-3564 affects the Content Blocks plugin for WordPress, specifically targeting versions up to and including 3.3.0. This represents a critical security flaw that exploits a local file inclusion vulnerability through the plugin's content_block shortcode functionality. The vulnerability is particularly concerning because it requires only contributor-level access or higher, making it accessible to users who should normally have limited privileges within a WordPress environment. The flaw stems from insufficient input validation and sanitization within the shortcode implementation, allowing malicious actors to manipulate file inclusion parameters and execute arbitrary PHP code on the affected server.
The technical exploitation of this vulnerability occurs through the content_block shortcode which fails to properly validate user-supplied input when processing file paths. Attackers can leverage this weakness by crafting malicious shortcode parameters that reference local files on the server, potentially including files that have been uploaded by the attacker or are part of the WordPress installation itself. This vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. The vulnerability also maps to ATT&CK technique T1059.007, which covers the execution of code through PHP, as attackers can execute arbitrary PHP code through the file inclusion mechanism.
The operational impact of this vulnerability is severe and multifaceted, as it enables authenticated attackers to bypass normal access controls and execute malicious code with the privileges of the web server. This can lead to complete compromise of the WordPress installation, allowing attackers to access sensitive data, modify content, install backdoors, or use the compromised system as a pivot point for attacking other systems within the network. The vulnerability is particularly dangerous because it can be exploited even when attackers only have contributor-level access, which is often granted to trusted users who contribute content to a website. The ability to include and execute arbitrary files means that attackers can potentially upload and execute malicious PHP files, creating persistent backdoors or performing data exfiltration operations.
Organizations should immediately update to the latest version of the Content Blocks plugin to remediate this vulnerability, as no official patches were available for versions prior to 3.3.1. The recommended mitigation strategy involves implementing strict input validation and sanitization for all user-supplied data, particularly in shortcode implementations and file inclusion mechanisms. Security administrators should also consider implementing web application firewalls to detect and block suspicious file inclusion patterns, and conduct thorough access control reviews to ensure that only authorized users have contributor-level privileges or higher. Additionally, monitoring for unusual file inclusion patterns and unauthorized file uploads should be implemented as part of ongoing security operations, as this vulnerability can be used to establish persistent access to compromised systems. The vulnerability demonstrates the critical importance of validating all user input and implementing proper access controls even for seemingly benign functionality within web applications.