CVE-2007-3429 in e107
Summary
by MITRE
Unrestricted file upload vulnerability in signup.php in e107 0.7.8 and earlier, when photograph upload is enabled, allows remote attackers to upload and execute arbitrary PHP code via a filename with a double extension such as .php.jpg.
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Analysis
by VulDB Data Team • 09/22/2024
The vulnerability identified as CVE-2007-3429 represents a critical unrestricted file upload flaw in the e107 content management system version 0.7.8 and earlier. This vulnerability specifically affects the signup.php script when photograph upload functionality is enabled, creating a pathway for remote attackers to bypass security measures and execute malicious code on the affected system. The flaw stems from inadequate input validation and sanitization of file upload parameters, allowing attackers to manipulate file extensions to circumvent security controls.
The technical implementation of this vulnerability exploits the predictable nature of file extension validation mechanisms within the e107 system. When photograph upload is enabled, the application fails to properly validate the file content and extension combination, permitting attackers to upload files with double extensions such as .php.jpg. This technique relies on the fact that many web servers and applications process file extensions from left to right, treating .jpg as the primary extension while ignoring the .php component. The vulnerability directly maps to CWE-434, which describes the weakness of unrestricted upload of executable files, and represents a classic example of improper input validation leading to code execution.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete control over the affected web server. Successful exploitation allows remote code execution, enabling attackers to upload backdoors, web shells, or other malicious payloads that can be used to maintain persistent access to the compromised system. This vulnerability can lead to full system compromise, data theft, service disruption, and potential lateral movement within network environments. The attack vector requires minimal privileges and can be executed remotely, making it particularly dangerous for web applications that handle user uploads.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The most effective immediate solution involves applying the official patch released by e107 developers, which corrects the file extension validation logic to properly sanitize and validate all uploaded files. Organizations should implement strict file type validation by checking both the file extension and MIME type, while also examining the actual file content to ensure it matches the claimed type. Additional protective measures include restricting file upload functionality to trusted users only, implementing proper file naming conventions that prevent double extensions, and configuring web servers to treat files with potentially dangerous extensions as non-executable. This vulnerability demonstrates the importance of following secure coding practices and implementing defense-in-depth strategies as outlined in the mitre attack framework, particularly focusing on preventing initial access through file upload vulnerabilities and maintaining proper input validation controls.