CVE-2006-3128 in easy-CMS
Summary
by MITRE
choose_file.php in easy-CMS 0.1.2, when mod_mime is installed, does not restrict uploads of filenames with multiple extensions, which allows remote attackers to execute arbitrary PHP code by uploading a PHP file with a GIF file extension, then directly accessing that file in the Repositories directory.
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Analysis
by VulDB Data Team • 07/29/2018
The vulnerability described in CVE-2006-3128 represents a critical file upload restriction flaw within the easy-CMS content management system version 0.1.2. This issue specifically affects systems where the mod_mime Apache module is enabled, creating a dangerous condition where the application fails to properly validate file extensions during the upload process. The vulnerability stems from the application's inability to effectively sanitize filenames that contain multiple extensions, allowing malicious actors to bypass security controls through clever file naming techniques.
The technical exploitation of this vulnerability relies on the specific behavior of mod_mime, which is an Apache module responsible for content negotiation and MIME type detection. When a PHP file is uploaded with a filename such as "malicious.php.gif" and the system processes this through mod_mime, the module may interpret the file as a GIF image rather than a PHP script due to the trailing .gif extension. This misinterpretation occurs because the web server's MIME type handling does not properly validate the actual file content against the claimed extension, creating a path traversal and code execution vulnerability.
The operational impact of this vulnerability is severe as it enables remote code execution without requiring authentication or privileged access. Attackers can upload malicious PHP scripts disguised as image files and then directly access these files through the Repositories directory, bypassing normal security controls. This allows for complete system compromise including data exfiltration, privilege escalation, and potential lateral movement within the network. The vulnerability is particularly dangerous because it exploits the trust relationship between the web server and file handling processes, making detection more challenging.
This vulnerability aligns with CWE-434, which describes "Unrestricted Upload of File with Dangerous Type," and represents a classic case of inadequate input validation and file extension handling. From an ATT&CK framework perspective, this corresponds to techniques involving T1190 - Exploit Public-Facing Application and T1059 - Command and Scripting Interpreter, as the vulnerability enables remote code execution through web application exploitation. The attack vector specifically maps to T1059.007 - PowerShell, but more accurately represents a general web-based code execution technique that bypasses traditional security controls.
Mitigation strategies for this vulnerability require multiple layers of defense including immediate patching of the easy-CMS application to version 0.1.3 or later, which should contain proper file extension validation and content type checking. Organizations should implement strict file type validation that checks both the file extension and actual file content using tools like file command or MIME type detection libraries. Additionally, the web server configuration should be modified to prevent execution of PHP files within upload directories, and proper file permissions should be enforced to restrict access to uploaded content. Network-based detection measures such as intrusion prevention systems should be configured to monitor for suspicious file upload patterns and direct access attempts to potentially malicious files in repository directories.