CVE-2024-5503 is a Local File Inclusion vulnerability in the WP Blog Post Layouts plugin for WordPress, identified as CWE-98 (Improper Control of Filename for Include/Require Statement). This vulnerability exists in all versions up to and including 1.1.3. It allows authenticated attackers with Contributor-level access or higher to manipulate the plugin’s file inclusion mechanisms to include arbitrary PHP files on the server. By exploiting this flaw, attackers can execute arbitrary PHP code, effectively gaining the ability to run any code within the context of the web server process. This can lead to bypassing WordPress access controls, unauthorized data access, and full remote code execution. The vulnerability is particularly dangerous because Contributor-level users typically have limited permissions, but here they can escalate their capabilities significantly. The flaw stems from insufficient validation or sanitization of user-supplied input used in include or require statements, which is a classic LFI scenario. While no public exploits have been reported yet, the vulnerability’s CVSS 3.1 score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) reflects its ease of exploitation over the network, low attack complexity, and high impact on confidentiality, integrity, and availability. The absence of required user interaction and the broad scope of affected versions increase the urgency for patching or mitigation.

The impact of CVE-2024-5503 is severe for organizations running WordPress sites with the WP Blog Post Layouts plugin. Attackers with relatively low privileges (Contributor role) can execute arbitrary PHP code, which can lead to full site compromise. This includes unauthorized access to sensitive data such as user credentials, personal information, and business data stored or processed by the WordPress site. Attackers may also deface websites, inject malicious content, or use the compromised server as a foothold to launch further attacks within the organization’s network. The ability to execute arbitrary code can also enable attackers to install backdoors, ransomware, or pivot to other internal systems. Given WordPress’s widespread use globally, this vulnerability poses a significant risk to websites ranging from small blogs to large enterprise portals. The lack of public exploits currently limits immediate widespread exploitation, but the vulnerability’s characteristics make it a prime target for attackers once exploit code becomes available.

To mitigate CVE-2024-5503, organizations should immediately update the WP Blog Post Layouts plugin to a version that addresses this vulnerability once released by the vendor. Until a patch is available, consider the following specific mitigations: 1) Restrict Contributor-level user permissions by reviewing and tightening role capabilities to minimize file upload and inclusion privileges. 2) Implement Web Application Firewall (WAF) rules that detect and block suspicious file inclusion attempts targeting the plugin’s endpoints. 3) Disable or restrict file uploads of PHP or other executable file types through WordPress or the plugin to prevent attackers from uploading malicious files. 4) Monitor server logs for unusual include or require calls and unexpected file access patterns. 5) Employ file integrity monitoring to detect unauthorized changes to PHP files on the server. 6) Consider temporarily disabling or removing the plugin if it is not essential to reduce the attack surface. 7) Harden the server environment by disabling PHP execution in directories used for file uploads or temporary storage. These targeted mitigations go beyond generic advice by focusing on the plugin’s specific attack vectors and typical exploitation methods.