CVE-2025-32028 in CMS PHP
Summary
by MITRE • 04/08/2025
HAX CMS PHP allows you to manage your microsite universe with PHP backend. Multiple file upload functions within the HAX CMS PHP application call a ’save’ function in ’HAXCMSFile.php’. This save function uses a denylist to block specific file types from being uploaded to the server. This list is non-exhaustive and only blocks ’.php’, ’.sh’, ’.js’, and ’.css’ files. The existing logic causes the system to "fail open" rather than "fail closed." This vulnerability is fixed in 10.0.3.
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Analysis
by VulDB Data Team • 07/30/2025
The HAX CMS PHP application presents a critical security vulnerability through its file upload functionality that stems from inadequate input validation and flawed access control mechanisms. This vulnerability exists within the HAXCMSFile.php component where multiple file upload operations invoke a save function that employs a denylist approach to prevent malicious file uploads. The denylist methodology, while seemingly logical, proves insufficient due to its non-exhaustive nature and failure to implement proper security boundaries. The system's design choice to "fail open" rather than "fail closed" creates a fundamental security flaw where the absence of explicit file type restrictions allows potentially dangerous files to be uploaded and executed on the server. This approach directly contravenes security best practices outlined in the OWASP Top Ten and aligns with CWE-434 which addresses insecure file upload vulnerabilities. The vulnerability specifically targets the denylist implementation in the save function, where only four file extensions are explicitly blocked: .php, .sh, .js, and .css. This limited blocking mechanism fails to account for numerous other potentially harmful file types that could be exploited for code execution or system compromise, including but not limited to .phtml, .php3, .php4, .php5, .php7, .phar, .pl, .cgi, .asp, .aspx, and various binary formats that might be misinterpreted by the web server.
The operational impact of this vulnerability extends far beyond simple file upload capabilities, creating a potential attack surface that could enable remote code execution and complete system compromise. When attackers exploit this flaw, they can upload malicious files that bypass the inadequate denylist protection, potentially leading to persistent backdoors, data exfiltration, or service disruption. The vulnerability's classification as a "fail open" design pattern places the system at significant risk since the default behavior allows all file types to be processed unless explicitly forbidden, rather than explicitly allowing only known safe types. This security misconfiguration creates a dangerous environment where attackers can leverage the system's trust in the denylist approach to bypass protections entirely. The vulnerability's persistence across versions prior to 10.0.3 indicates a long-standing design flaw that could have been exploited for extended periods, potentially allowing attackers to establish footholds and escalate privileges within the affected environments. Organizations using HAX CMS PHP versions before the patched release face substantial risk of unauthorized access and system compromise, as the vulnerability enables attackers to upload and execute arbitrary code on the web server.
The mitigation strategy for this vulnerability requires immediate implementation of comprehensive security measures that address both the immediate flaw and prevent similar issues in the future. The most direct solution involves upgrading to version 10.0.3 where the vulnerability has been patched, but organizations should also implement additional protective measures such as implementing allowlists for file types rather than denylists, enforcing strict file content validation, and configuring proper file permissions and execution controls. The fix should incorporate proper input sanitization and validation techniques that align with the principle of least privilege and fail-closed security models. Organizations should also consider implementing web application firewalls to monitor and block suspicious file upload attempts, conducting regular security audits of file handling mechanisms, and establishing proper logging and monitoring for file upload activities. The vulnerability's resolution demonstrates the importance of proper security architecture decisions where denylist approaches should never be the sole mechanism for preventing malicious file uploads, as they inherently suffer from the problem of unknown unknowns in threat landscapes. This vulnerability reinforces the ATT&CK framework's relevance in understanding how file upload vulnerabilities can be leveraged for initial access and privilege escalation, particularly through techniques such as web shell deployment and code injection attacks. The remediation process should include comprehensive testing of file upload functionality to ensure that the new security measures properly validate file types and content, and that the system correctly rejects potentially dangerous uploads while maintaining legitimate functionality for authorized users.