CVE-2009-3535 in Clear Content
Summary
by MITRE
Directory traversal vulnerability in image.php in Clear Content 1.1 allows remote attackers to read arbitrary files via a .. (dot dot) in the url parameter. NOTE: the researcher also suggests an analogous PHP remote file inclusion vulnerability, but this may be incorrect.
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Analysis
by VulDB Data Team • 03/12/2025
The vulnerability identified as CVE-2009-3535 resides within the Clear Content 1.1 web application, specifically in the image.php script that handles image processing functionality. This directory traversal flaw represents a critical security weakness that enables remote attackers to access arbitrary files on the affected system through manipulation of the url parameter. The vulnerability stems from inadequate input validation and sanitization mechanisms within the application's file handling routines, allowing malicious users to exploit the system's file system access controls through carefully crafted requests containing directory traversal sequences.
The technical exploitation of this vulnerability relies on the manipulation of the url parameter to include .. (dot dot) sequences that traverse up the directory hierarchy, thereby bypassing intended file access restrictions. When the image.php script processes such requests without proper validation, it fails to sanitize the input path, allowing attackers to navigate to arbitrary locations within the server's file system. This flaw operates at the application layer and demonstrates a classic path traversal vulnerability pattern that has been documented extensively in security literature and categorized under CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory. The vulnerability's impact extends beyond simple file reading, as it can potentially expose sensitive system files, configuration data, and other confidential information stored on the web server.
From an operational perspective, this vulnerability presents a significant risk to organizations deploying Clear Content 1.1, as it enables attackers to extract sensitive data without authentication or authorization. The implications include potential exposure of database credentials, application configuration files, user data, and system configuration information that could lead to further compromise of the affected environment. Security professionals should note that this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1083 - File and Directory Discovery tactic, as attackers can systematically enumerate and access files on the compromised system. The vulnerability's remote nature means that exploitation can occur from any location with internet access, making it particularly dangerous for publicly accessible web applications.
The remediation strategy for this vulnerability requires immediate implementation of proper input validation and sanitization measures within the image.php script. Organizations should implement strict path validation that ensures all file access requests are confined to predetermined directories and reject any input containing directory traversal sequences. The solution involves implementing a whitelist approach for valid file paths, where only explicitly allowed directories and file extensions are permitted for processing. Additionally, the application should employ proper access control mechanisms that prevent traversal beyond the intended file system boundaries. Security patches or code modifications should be implemented to sanitize all user-supplied input, particularly parameters used in file system operations. System administrators should also consider implementing web application firewalls and input validation rules to prevent such attacks at the network perimeter, while monitoring for anomalous file access patterns that may indicate exploitation attempts. The vulnerability's classification under CWE-22 and its operational impact make it a critical priority for immediate remediation across all affected systems.