CVE-2007-4057 in Seditio
Summary
by MITRE
Unrestricted file upload vulnerability in pfs.php in Neocrome Seditio 121 and earlier allows remote authenticated users to upload arbitrary PHP code via a filename ending with (1) .php.gif, (2) .php.jpg, or (3) .php.png.
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Analysis
by VulDB Data Team • 09/29/2024
The vulnerability identified as CVE-2007-4057 represents a critical unrestricted file upload flaw in the pfs.php component of Neocrome Seditio versions 121 and earlier. This vulnerability occurs within the file upload functionality that fails to properly validate file extensions and content, creating a pathway for malicious actors to bypass security measures and execute arbitrary code on the affected system. The flaw specifically targets the validation logic that should prevent execution of PHP code through file uploads, allowing attackers to exploit this weakness by using file names with specific extensions that can be interpreted as images but contain executable PHP code.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the file upload process. Attackers can leverage this weakness by uploading files with extensions such as .php.gif, .php.jpg, or .php.png which, while appearing to be image files, actually contain PHP code that can be executed by the web server. This technique exploits the way certain web servers handle file extensions and MIME type detection, where files with these specific extensions may be processed as images but still retain their executable PHP capabilities. The vulnerability is particularly dangerous because it allows authenticated users to perform this attack, meaning the malicious actor has already established some level of access to the system, reducing the attack surface complexity.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with persistent access to the compromised system. Once the malicious PHP code is uploaded and executed, it can be used to establish backdoors, perform further reconnaissance, escalate privileges, or create additional attack vectors within the network. The vulnerability affects the core file management functionality of Seditio, which typically handles user-generated content, making it a critical component for attackers seeking to maintain persistent access. According to CWE standards, this maps to CWE-434 which describes "Unrestricted Upload of File with Dangerous Type," a well-documented weakness that has been repeatedly exploited in various web applications throughout the years.
The exploitation of this vulnerability aligns with several techniques documented in the MITRE ATT&CK framework, particularly in the execution and persistence phases. Attackers can leverage this vulnerability to achieve code execution through the uploaded PHP files, which can then be used to maintain persistence on the compromised system. The vulnerability also supports privilege escalation attacks where the uploaded code can be used to gain higher-level access within the application or system. The authentication requirement for exploitation means that attackers must first obtain valid credentials, but this is often achievable through social engineering, credential theft, or other initial compromise techniques that are well-documented in the threat landscape.
Mitigation strategies for this vulnerability should focus on implementing comprehensive file validation and sanitization measures within the application. The most effective approach involves implementing strict file type validation that rejects any file with extensions that could potentially contain executable code, regardless of the file content. Organizations should also implement proper file name sanitization to prevent the use of potentially dangerous extensions in uploaded files. Additionally, the system should employ proper file handling mechanisms that separate uploaded files from executable code, ensuring that even if a malicious file is uploaded, it cannot be directly executed by the web server. The implementation of Content Security Policies and proper web server configuration can further reduce the risk of exploitation. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other parts of the application, as this type of flaw is commonly found in legacy web applications and represents a classic example of inadequate input validation that can be addressed through proper security development practices.