CVE-2012-2902 in Joomla Content Editor
Summary
by MITRE
Unrestricted file upload vulnerability in editor/extensions/browser/file.php in the Joomla Content Editor (JCE) component before 2.1 for Joomla!, when chunking is set to greater than zero, allows remote authors to execute arbitrary PHP code by uploading a PHP file with a double extension as demonstrated by .jpg.pht.
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Analysis
by VulDB Data Team • 04/23/2025
The CVE-2012-2902 vulnerability represents a critical unrestricted file upload flaw in the Joomla Content Editor component that fundamentally undermines web application security. This vulnerability specifically affects JCE versions prior to 2.1 and exists within the file.php script located in the editor/extensions/browser/ directory. The flaw becomes particularly dangerous when the chunking functionality is enabled with values greater than zero, creating a pathway for malicious actors to bypass standard file validation mechanisms. The vulnerability operates through a sophisticated technique involving double extensions, where attackers can upload files with names like .jpg.pht that appear to be legitimate image files but actually contain executable PHP code. This vulnerability maps directly to CWE-434 which addresses insecure file upload vulnerabilities, where the system fails to properly validate file types and extensions.
The technical exploitation of this vulnerability relies on the component's inadequate input validation and file handling processes. When chunking is enabled, the upload process splits large files into smaller pieces for transmission, but this functionality introduces a critical gap in security checks. Attackers can leverage this by creating a file with a double extension such as image.jpg.pht where the system may accept the .jpg extension as legitimate while the .pht portion remains undetected during the upload validation process. The uploaded file then gets stored on the server with its original extension, allowing the web server to execute the PHP code contained within the file. This technique exploits the fundamental weakness in how the application processes file extensions and the lack of proper content type validation. The vulnerability aligns with ATT&CK technique T1505.003 which covers "Obfuscated Files or Information" and T1190 which addresses "Exploit Public-Facing Application".
The operational impact of CVE-2012-2902 is severe and far-reaching for affected Joomla installations. Successful exploitation allows remote attackers to execute arbitrary PHP code with the privileges of the web server process, potentially leading to complete system compromise. Attackers can upload backdoor files, web shells, or other malicious payloads that provide persistent access to the compromised system. The vulnerability enables attackers to perform actions such as data exfiltration, system enumeration, privilege escalation, and further network infiltration. Organizations using vulnerable JCE components face significant risk of data breaches, service disruption, and potential regulatory violations. The impact extends beyond immediate system compromise to include long-term security degradation of the entire web infrastructure. This vulnerability demonstrates the critical importance of proper input validation and file handling in web applications, particularly in content management systems where users have the ability to upload content.
Mitigation strategies for CVE-2012-2902 require immediate action to address the root cause. The primary and most effective solution involves upgrading to JCE version 2.1 or later, which includes proper file validation and content type checking mechanisms. Organizations should implement comprehensive file upload restrictions that reject files with double extensions or suspicious file types. The implementation of Content Security Policies and proper MIME type validation can provide additional layers of protection. Security measures should include disabling chunking functionality when it's not required, implementing strict file extension whitelisting, and conducting regular security audits of uploaded content. Network-based protections such as web application firewalls can help detect and block suspicious upload attempts. Additionally, organizations should establish proper access controls and monitoring for file upload operations, ensuring that only authorized users can perform these actions. The remediation process should also include comprehensive security training for administrators and developers to understand the importance of proper file handling and validation in web applications.