CVE-2021-24375 in Motor Theme
Summary
by MITRE • 07/06/2021
Lack of authentication or validation in motor_load_more, motor_gallery_load_more, motor_quick_view and motor_project_quick_view AJAX handlers of the Motor WordPress theme before 3.1.0 allows an unauthenticated attacker access to arbitrary files in the server file system, and to execute arbitrary php scripts found on the server file system. We found no vulnerability for uploading files with this theme, so any scripts to be executed must already be on the server file system.
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Analysis
by VulDB Data Team • 07/09/2021
The CVE-2021-24375 vulnerability represents a critical authentication and authorization flaw within the Motor WordPress theme affecting versions prior to 3.1.0. This vulnerability manifests through four specific AJAX handlers: motor_load_more, motor_gallery_load_more, motor_quick_view, and motor_project_quick_view. These handlers lack proper authentication mechanisms and input validation, creating a pathway for unauthenticated attackers to exploit the theme's functionality. The vulnerability stems from insufficient access controls that fail to verify user credentials or permissions before processing requests, directly violating fundamental security principles of least privilege and proper authentication.
The technical implementation of this vulnerability allows attackers to manipulate the AJAX handlers to access arbitrary files within the server's file system. This occurs because the theme's code does not validate the source or legitimacy of requests sent to these handlers, enabling malicious actors to craft requests that traverse the file system and retrieve sensitive data. The vulnerability also permits execution of arbitrary PHP scripts that already exist on the server, meaning attackers can leverage existing malicious code rather than requiring upload capabilities. This execution capability represents a severe compromise as it allows for remote code execution on the target server, potentially enabling full system compromise. The absence of file upload capabilities in this specific vulnerability means that attackers must already have PHP scripts present on the server to achieve execution, but this still represents a significant security risk as it allows for exploitation of existing malicious payloads.
The operational impact of CVE-2021-24375 extends beyond simple data exposure, as it creates a persistent threat vector that can be exploited repeatedly without requiring additional compromise steps. Attackers can leverage this vulnerability to enumerate server directories, access configuration files, database credentials, and other sensitive information stored in the file system. The ability to execute arbitrary PHP code transforms this vulnerability from a mere information disclosure issue into a full remote code execution threat. This capability aligns with ATT&CK technique T1059.007 for PHP, where adversaries leverage existing PHP scripts on compromised systems to execute malicious commands. The vulnerability also maps to CWE-285, which addresses improper authorization in software, and CWE-79, which covers cross-site scripting vulnerabilities that can be exploited to gain unauthorized access. Organizations using affected versions of the Motor theme face significant risk of data breaches, system compromise, and potential lateral movement within their networks.
Mitigation strategies for CVE-2021-24375 require immediate action to upgrade to Motor theme version 3.1.0 or later, which contains the necessary authentication and validation patches. System administrators should also implement additional protective measures including restricting access to AJAX endpoints through web application firewalls, implementing rate limiting to prevent automated exploitation attempts, and conducting comprehensive security audits of the WordPress installation. Network segmentation and monitoring solutions should be deployed to detect anomalous requests to these AJAX handlers. The vulnerability highlights the importance of proper input validation and authentication checks in web applications, aligning with security best practices outlined in OWASP Top Ten and NIST cybersecurity frameworks. Regular security updates and vulnerability assessments should be implemented as part of ongoing security operations to prevent similar issues from arising in other components of the WordPress ecosystem.