CVE-2014-3782 in Dotclear
Summary
by MITRE
Multiple incomplete blacklist vulnerabilities in the filemanager::isFileExclude method in the Media Manager in Dotclear before 2.6.3 allow remote authenticated users to execute arbitrary PHP code by uploading a file with a (1) double extension or (2) .php5, (3) .phtml, or some other PHP file extension.
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Analysis
by VulDB Data Team • 03/10/2019
The vulnerability identified as CVE-2014-3782 represents a critical security flaw in the Dotclear content management system affecting versions prior to 2.6.3. This issue resides within the Media Manager component's filemanager::isFileExclude method, which implements an incomplete blacklist approach for file validation. The flaw stems from insufficient input sanitization and validation mechanisms that fail to properly handle various PHP file extensions, creating a pathway for remote authenticated attackers to execute arbitrary code on the affected system. The vulnerability specifically targets the file upload functionality where the application attempts to prevent the upload of potentially malicious files through a filtering mechanism that proves inadequate against sophisticated attack vectors.
The technical implementation of this vulnerability exploits the incomplete blacklist approach by leveraging file extensions that bypass the validation checks. Attackers can successfully upload malicious PHP files by using double extensions such as .jpg.php or .php5, .phtml, and other PHP-related extensions that are not properly accounted for in the exclusion list. This weakness manifests because the blacklist validation does not consider the full range of PHP file extensions that could potentially be executed by the web server, nor does it properly handle cases where file extensions are obscured through double extensions. The vulnerability operates at the application layer and requires authentication to exploit, making it particularly dangerous as it allows authenticated users to escalate their privileges and gain unauthorized code execution capabilities.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to compromise the entire web application and potentially the underlying server infrastructure. Remote authenticated users can upload malicious PHP files that execute arbitrary commands, potentially leading to data breaches, server compromise, and complete system takeover. The vulnerability affects the core functionality of the Dotclear platform and could result in unauthorized access to sensitive data, modification of content, and establishment of persistent backdoors. Organizations using affected versions of Dotclear face significant risk of unauthorized code execution and potential data loss, particularly in environments where the application is exposed to untrusted users.
The vulnerability aligns with CWE-434, which describes "Unrestricted Upload of File with Dangerous Type," and represents a classic example of insecure file upload validation. From an ATT&CK framework perspective, this vulnerability maps to T1190 - Exploit Public-Facing Application, where attackers leverage application weaknesses to execute code, and T1059 - Command and Scripting Interpreter, as the uploaded PHP files can execute system commands. The incomplete blacklist approach violates security best practices by relying on a finite list of known malicious extensions rather than implementing proper whitelisting or comprehensive validation mechanisms. Organizations should implement immediate mitigations including upgrading to Dotclear version 2.6.3 or later, implementing robust file type validation, and deploying additional security controls such as web application firewalls to prevent exploitation of this vulnerability.