CVE-2018-12995 in OneFileCMS
Summary
by MITRE
onefilecms.php in OneFileCMS through 2012-04-14 might allow attackers to execute arbitrary PHP code via a .php filename on the Upload screen.
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Analysis
by VulDB Data Team • 02/23/2020
The vulnerability identified as CVE-2018-12995 affects OneFileCMS versions up to and including the 2012-04-14 release, presenting a critical security flaw in the file upload functionality. This issue resides within the onefilecms.php component which handles file uploads through the web interface. The vulnerability stems from inadequate input validation and sanitization of filenames during the upload process, creating an avenue for remote code execution attacks. Attackers can exploit this weakness by uploading malicious files with .php extensions, effectively bypassing intended security restrictions that should prevent execution of PHP code within the upload directory.
The technical flaw manifests as a lack of proper filename validation and sanitization mechanisms. When users attempt to upload files through the CMS interface, the application fails to properly verify or sanitize the file extensions provided in the upload request. This weakness allows attackers to submit filenames ending with .php extensions, which are then processed and stored on the server without adequate security checks. The vulnerability directly maps to CWE-434 which describes insecure file upload handling, where applications accept files from untrusted sources without proper validation of file type, content, or extension. The flaw represents a classic case of insufficient input sanitization and inadequate access controls in web applications.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with complete remote code execution capabilities on the affected system. Once successfully exploited, attackers can execute arbitrary PHP code with the privileges of the web server process, potentially leading to full system compromise. This vulnerability enables attackers to upload backdoor scripts, web shells, or other malicious payloads that can be executed at will, allowing for persistent access, data exfiltration, and further network exploitation. The attack surface is particularly dangerous because it operates within the legitimate CMS upload functionality, making it difficult to detect through standard network monitoring. The vulnerability also aligns with ATT&CK technique T1190 which describes exploiting vulnerabilities in web applications to establish persistence and execute commands.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The most effective immediate solution involves applying the vendor-provided patch or upgrading to a version that resolves this issue, as no official patch was available for this specific vulnerability at the time of reporting. Organizations should implement strict file type validation by rejecting uploads with .php extensions or other potentially dangerous file extensions such as .phtml, .php3, .php4, .php5, .php7, .phar, .cgi, .pl, .sh, .asp, .aspx, and .jsp. Additionally, uploaded files should be stored outside the web root directory and renamed using a secure, random naming scheme to prevent direct access. The implementation of Content Security Policy headers and proper file permission settings can further reduce the risk. Organizations should also conduct regular security audits of their CMS installations, implement web application firewalls, and establish monitoring for suspicious upload activities. These measures align with security best practices outlined in the OWASP Top Ten and NIST cybersecurity frameworks, particularly addressing the critical need for secure file upload handling and input validation.