CVE-2005-1898 in phpThumb
Summary
by MITRE
The passthrough functionality in phpThumb.php in phpThumb() before 1.5.4 allows remote attackers to read files that are not images.
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Analysis
by VulDB Data Team • 07/09/2018
The vulnerability identified as CVE-2005-1898 represents a critical security flaw in the phpThumb() library that affected versions prior to 1.5.4. This vulnerability resides within the passthrough functionality of the phpThumb.php script, which is designed to handle image processing and manipulation tasks. The issue stems from inadequate input validation and access control mechanisms that permit unauthorized file access through the image processing pipeline. The vulnerability is classified under CWE-22 as "Improper Limiting of a Pathname to a Known Good Path" and falls within the broader category of path traversal attacks that have been consistently documented in cybersecurity literature.
The technical flaw manifests when the passthrough functionality processes image requests without properly sanitizing the input parameters that specify which files should be processed or accessed. Attackers can exploit this weakness by crafting malicious requests that bypass normal image processing restrictions and gain access to arbitrary files on the server. The vulnerability specifically allows remote attackers to read non-image files, potentially including configuration files, source code, database credentials, and other sensitive data that should remain protected from public access. This occurs because the application fails to properly validate or restrict the file paths that can be accessed through the image processing interface, creating a direct pathway to the file system that should be protected by proper access controls.
The operational impact of this vulnerability is severe and far-reaching for any web application utilizing the affected version of phpThumb(). Organizations running vulnerable versions face significant risk of data exposure, as attackers can potentially extract sensitive information such as database connection strings, application configuration files, and other proprietary data stored on the same server. The remote nature of the attack means that threat actors do not require local access or authentication credentials to exploit the vulnerability, making it particularly dangerous for web applications that process user-uploaded content or serve dynamic image requests. This vulnerability directly aligns with ATT&CK technique T1566.001 "Phishing: Spearphishing Attachment" and T1083 "File and Directory Discovery" when attackers leverage such flaws to enumerate and extract sensitive data from compromised systems.
The security implications extend beyond simple file access, as this vulnerability can serve as a stepping stone for more sophisticated attacks. Once an attacker gains access to sensitive files through this vulnerability, they can potentially escalate their privileges, extract additional credentials, or use the exposed information to launch further attacks against the internal network infrastructure. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in web application security design. Organizations should immediately implement mitigations including updating to phpThumb version 1.5.4 or later, implementing proper input sanitization, and configuring access controls that prevent direct file system access through image processing interfaces. Additionally, network monitoring should be enhanced to detect unusual patterns of file access requests that might indicate exploitation attempts, and regular security audits should verify that no other similar vulnerabilities exist in the application's codebase.