CVE-2011-5083 in Dotclear
Summary
by MITRE
Unrestricted file upload vulnerability in inc/swf/swfupload.swf in Dotclear 2.3.1 and 2.4.2 allows remote attackers to execute arbitrary code by uploading a file with an executable PHP extension, then accessing it via a direct request to the file in an unspecified directory.
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Analysis
by VulDB Data Team • 04/09/2025
The vulnerability identified as CVE-2011-5083 represents a critical unrestricted file upload flaw within the Dotclear content management system versions 2.3.1 and 2.4.2. This vulnerability resides in the swfupload.swf component located within the inc/swf/ directory structure, which is part of the application's file upload functionality. The flaw allows malicious actors to bypass normal file validation mechanisms and upload potentially harmful files to the target system. The vulnerability specifically affects the SWFUpload library implementation within Dotclear's web application framework, creating an attack vector that can be exploited without requiring authentication or specific user interaction beyond initial access to the vulnerable system.
The technical exploitation of this vulnerability occurs through the manipulation of file upload processes that do not properly validate file extensions or content types. Attackers can upload PHP files with executable extensions such as .php, .php3, .php4, or .php5, which are then stored on the web server in an unspecified directory. Once uploaded, these malicious files become accessible via direct HTTP requests to their locations, enabling remote code execution capabilities. The vulnerability stems from inadequate input validation and sanitization within the file upload handler, allowing attackers to circumvent security controls that should prevent the upload of executable scripts. This flaw aligns with CWE-434, which describes unrestricted upload of files with dangerous types that can lead to arbitrary code execution, and represents a classic example of insecure file handling in web applications.
The operational impact of CVE-2011-5083 is severe and multifaceted, potentially allowing attackers to gain complete control over affected web servers. Successful exploitation enables remote code execution, which can result in data theft, service disruption, system compromise, and lateral movement within network environments. The vulnerability can be leveraged to establish persistent backdoors, deploy additional malware, or use the compromised system as a launch point for attacks against other systems. Organizations running vulnerable Dotclear installations face significant risks including unauthorized access to sensitive data, potential regulatory compliance violations, and reputational damage. The attack surface is particularly concerning because it requires minimal privileges to exploit and can be automated, making it attractive to both opportunistic attackers and organized threat groups. According to ATT&CK framework, this vulnerability maps to T1190 (Exploit Public-Facing Application) and T1059 (Command and Scripting Interpreter) techniques, demonstrating how initial access can quickly escalate to full system compromise.
Mitigation strategies for CVE-2011-5083 should focus on immediate patching of affected Dotclear versions, as the vulnerability has been addressed in subsequent releases. Organizations must implement comprehensive file upload restrictions including strict file type validation, mandatory file extension filtering, and content-based verification. The recommended approach involves configuring web servers to reject executable file uploads and implementing proper directory permissions to prevent direct access to uploaded files. Additionally, organizations should deploy web application firewalls to monitor and block suspicious upload attempts, and establish robust monitoring procedures to detect unauthorized file uploads. Security measures should include regular vulnerability assessments, proper input validation at multiple layers, and implementation of least privilege principles for file upload functionality. The remediation process should also include reviewing and updating security configurations, implementing proper logging and alerting mechanisms, and conducting regular security training for administrators to prevent similar vulnerabilities in other applications.