CVE-2020-35239 in CakePHP
Summary
by MITRE • 01/26/2021
A vulnerability exists in CakePHP versions 4.0.x through 4.1.3. The CsrfProtectionMiddleware component allows method override parameters to bypass CSRF checks by changing the HTTP request method to an arbitrary string that is not in the list of request methods that CakePHP checks. Additionally, the route middleware does not verify that this overriden method (which can be an arbitrary string) is actually an HTTP method.
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Analysis
by VulDB Data Team • 05/04/2025
The vulnerability identified as CVE-2020-35239 resides within the CakePHP web application framework, specifically affecting versions 4.0.x through 4.1.3. This security flaw impacts the CsrfProtectionMiddleware component which is designed to prevent cross-site request forgery attacks by validating request authenticity. The vulnerability stems from insufficient validation of HTTP method override parameters, creating a pathway for attackers to bypass critical security controls that protect against unauthorized actions. The issue manifests when the framework allows method override parameters to change the HTTP request method to arbitrary strings that fall outside the standard list of HTTP methods that CakePHP validates, effectively circumventing the intended protection mechanisms.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP method override functionality within the framework's routing system. When an attacker submits a request with a method override parameter containing an arbitrary string that is not recognized as a standard HTTP method, the CsrfProtectionMiddleware fails to properly validate this input. This flaw exists because the route middleware does not perform adequate verification to ensure that overridden methods are actually valid HTTP methods, allowing malicious inputs to pass through without proper scrutiny. The vulnerability specifically targets the framework's security model where method overrides are expected to be constrained to recognized HTTP methods such as GET, POST, PUT, DELETE, and others.
The operational impact of CVE-2020-35239 represents a significant security risk for applications relying on CakePHP's CSRF protection mechanisms. Attackers can leverage this vulnerability to bypass CSRF protections and execute unauthorized actions against vulnerable applications, potentially leading to data manipulation, unauthorized user actions, or privilege escalation within the affected systems. The flaw essentially allows attackers to forge requests that appear legitimate to the application's security controls while bypassing the fundamental CSRF protection that should prevent such unauthorized operations. This vulnerability directly violates the principle of least privilege and can enable attackers to perform actions they should not be authorized to execute.
This vulnerability maps to CWE-346 known as "Missing Verification of Data Authenticity", which addresses the failure to verify that data received from untrusted sources has not been tampered with or manipulated. The flaw also aligns with ATT&CK technique T1213.002 for Data from Information Repositories, as it allows unauthorized access to application resources through manipulation of request parameters. Additionally, the vulnerability relates to T1078.004 for Valid Accounts, as successful exploitation may enable attackers to perform actions using legitimate application accounts through bypassed security controls. Organizations using affected CakePHP versions should immediately implement mitigations including upgrading to patched versions, implementing additional input validation layers, and monitoring for suspicious request patterns that may indicate exploitation attempts.
The recommended mitigations for CVE-2020-35239 include upgrading to CakePHP versions that contain the appropriate security fixes, typically version 4.1.4 or later. Administrators should also implement additional validation controls that explicitly check method override parameters against a whitelist of recognized HTTP methods before processing requests. Network monitoring solutions should be configured to detect unusual method override patterns, and application firewalls should be deployed to filter out suspicious parameter values. Regular security audits of application configurations should verify that CSRF protection mechanisms are properly enforced and that method override functionality is appropriately constrained to prevent arbitrary string inputs from bypassing security controls. The vulnerability serves as a reminder of the importance of proper input validation and the necessity of maintaining up-to-date security patches in web application frameworks to prevent exploitation of known security flaws.