CVE-2009-3538 in Clear Content
Summary
by MITRE
Directory traversal vulnerability in thumb.php in Clear Content 1.1 allows remote attackers to read arbitrary files via a .. (dot dot) in the url parameter. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.
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Analysis
by VulDB Data Team • 08/28/2017
The vulnerability identified as CVE-2009-3538 represents a critical directory traversal flaw in the Clear Content 1.1 web application's thumb.php script. This vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied URL parameters before processing file operations. The flaw specifically manifests when the application accepts a url parameter containing directory traversal sequences such as .. (dot dot) which allows malicious actors to navigate outside the intended directory structure and access arbitrary files on the server filesystem. The vulnerability is classified under CWE-22 as Improper Limitation of a Pathname to a Restricted Directory, which is a fundamental security weakness that enables attackers to bypass normal access controls and retrieve sensitive information from the web server.
The technical exploitation of this vulnerability occurs through the manipulation of the url parameter in the thumb.php script, where attackers can append directory traversal sequences to access files that should remain protected within the application's designated directories. This type of vulnerability falls under the ATT&CK technique T1083 - File and Directory Discovery, as it enables adversaries to enumerate and access files that are not intended to be publicly accessible. The impact extends beyond simple information disclosure, as attackers can potentially access configuration files, database credentials, application source code, and other sensitive data that may lead to further compromise of the system. The vulnerability is particularly dangerous because it allows remote code execution capabilities when combined with other exploitation techniques, as attackers can read files that may contain database connection strings, API keys, or other credentials that could be leveraged for deeper system access.
From an operational standpoint, this vulnerability creates significant risk for organizations using Clear Content 1.1 as it provides attackers with an easy method to gain unauthorized access to sensitive server files without requiring authentication or specialized privileges. The vulnerability exists in the application's file handling mechanism where input validation is insufficient to prevent malicious path manipulation attempts. The exploitation process requires minimal technical skill and can be automated, making it particularly attractive to threat actors. Organizations may face regulatory compliance violations if sensitive data is accessed through this vulnerability, as it directly impacts data confidentiality and integrity. The vulnerability also demonstrates poor security practices in input validation and access control implementation, which are fundamental requirements for secure web application development as outlined in OWASP Top 10 and ISO/IEC 27001 standards.
Mitigation strategies for CVE-2009-3538 should focus on implementing robust input validation and sanitization measures that prevent directory traversal sequences from being processed by the application. The recommended approach involves implementing a whitelist-based validation system that only accepts predetermined, safe file paths and rejects any input containing traversal sequences such as .. or %2e%2e. Organizations should also implement proper access controls and file permissions that limit the web server's ability to access sensitive directories even if traversal attempts are successful. Additionally, the application should be updated to a patched version that properly handles file path validation and implements proper input sanitization techniques. Security monitoring should be enhanced to detect suspicious file access patterns and directory traversal attempts, while regular security assessments should be conducted to identify similar vulnerabilities in other web applications. The vulnerability serves as a reminder of the critical importance of implementing secure coding practices and proper input validation to prevent attackers from exploiting fundamental flaws in web application architectures.