CVE-2013-3631 in NAS4Free
Summary
by MITRE
NAS4Free 9.1.0.1.804 and earlier allows remote authenticated users to execute arbitrary PHP code via a request to exec.php, aka the "Advanced | Execute Command" feature. NOTE: this issue might not be a vulnerability, since it appears to be part of legitimate, intentionally-exposed functionality by the developer and is allowed within the intended security policy.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2013-3631 affects NAS4Free versions 9.1.0.1.804 and earlier, presenting a critical security risk through its Advanced | Execute Command feature. This flaw exists within the exec.php component of the network-attached storage operating system, which was designed to provide administrative functionality for executing system commands. The vulnerability arises from insufficient input validation and access control measures within the web interface, allowing authenticated users to inject and execute arbitrary PHP code on the underlying system.
The technical implementation of this vulnerability stems from improper sanitization of user-supplied input parameters within the exec.php script. When authenticated users access the Advanced | Execute Command interface, the application fails to properly validate or escape command-line arguments before incorporating them into system execution contexts. This creates a path for privilege escalation and code injection attacks where malicious input can be interpreted and executed as PHP code rather than being treated as simple command parameters. The vulnerability falls under CWE-94, which specifically addresses "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1059.006 for "Command and Scripting Interpreter: Python" within the execution phase of the attack lifecycle.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to gain elevated privileges and potentially compromise the entire network-attached storage infrastructure. An authenticated user can leverage this flaw to execute arbitrary system commands, access sensitive data, modify system configurations, or establish persistent access through backdoor installations. The vulnerability's severity is amplified by the fact that it requires only authentication credentials, which are often less protected than administrative passwords in many network environments. This creates a dangerous scenario where compromised user accounts can be leveraged to achieve system-level compromise, particularly in environments where NAS4Free serves as a central storage solution for critical data.
Security mitigations for this vulnerability should focus on immediate remediation through software updates to versions that address the input validation flaws in the exec.php component. Organizations should implement strict access controls and privilege separation, ensuring that only essential administrative users have access to command execution features. Network segmentation and monitoring of suspicious command execution patterns can help detect exploitation attempts. Additionally, implementing web application firewalls and input validation rules can provide defense-in-depth measures. The vulnerability's classification as potentially intentional functionality by the developer highlights the importance of security policy reviews and the need for organizations to understand the security implications of legitimate features within their systems. Regular security assessments and penetration testing should be conducted to identify similar issues in other components of the NAS4Free platform and similar network storage solutions.