CVE-2013-4949 in Machform
Summary
by MITRE
Unrestricted file upload vulnerability in view.php in Machform 2 allows remote attackers to execute arbitrary PHP code by uploading a PHP file, then accessing it via a direct request to the file in the upload form s directory in data/.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/20/2025
The CVE-2013-4949 vulnerability represents a critical unrestricted file upload flaw in Machform 2's view.php component that enables remote attackers to achieve arbitrary code execution through a straightforward exploitation technique. This vulnerability resides within the file upload handling mechanism of the web application, specifically targeting the data/ directory where uploaded files are stored. The flaw stems from inadequate input validation and sanitization processes that fail to properly verify the file types being uploaded, allowing malicious actors to bypass security controls and deploy malicious PHP scripts directly into the application's file system.
The technical exploitation of this vulnerability follows a well-defined attack pattern that aligns with common web application security weaknesses categorized under CWE-434. Attackers can upload a PHP shell or malicious script file through the vulnerable upload form, which then gets stored in the data/ directory. Once the file is successfully uploaded, the attacker can directly access it by making a request to the file's location within the upload directory, thereby executing arbitrary PHP code on the target server. This represents a classic case of insufficient file type validation and improper file handling that allows attackers to escalate privileges and gain control over the affected system.
The operational impact of this vulnerability extends far beyond simple code execution, as it provides attackers with complete control over the affected web server and potentially the underlying infrastructure. The vulnerability allows for persistent access through uploaded malware, which can be used to establish backdoors, exfiltrate sensitive data, or use the compromised server as a launching point for further attacks within the network. The attack vector is particularly dangerous because it requires minimal privileges to exploit and can be automated, making it attractive to both automated malware and sophisticated attackers. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1190 (Exploit Public-Facing Application) and T1059 (Command and Scripting Interpreter) categories.
Organizations using Machform 2 are particularly vulnerable to this attack due to the lack of proper file extension validation and content type checking in the upload process. The vulnerability demonstrates a fundamental flaw in the application's security architecture where the system trusts user input without proper sanitization, creating an attack surface that can be leveraged for privilege escalation and persistent access. Mitigation strategies should include implementing strict file type validation, using random or non-predictable filenames for uploads, storing uploaded files outside the web root, and implementing proper access controls on the upload directory. Additionally, regular security audits and input validation mechanisms should be enforced to prevent similar vulnerabilities from occurring in other components of the application stack. The vulnerability also highlights the importance of following secure coding practices and implementing proper defense-in-depth strategies to prevent attackers from exploiting common web application flaws that have been well-documented in security literature and frameworks.