CVE-2015-4726 in AudioShare
Summary
by MITRE
PHP remote file inclusion vulnerability in ajax/myajaxphp.php in AudioShare 2.0.2 allows remote attackers to execute arbitrary PHP code via a URL in the config['basedir'] parameter.
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Analysis
by VulDB Data Team • 04/14/2019
The CVE-2015-4726 vulnerability represents a critical remote file inclusion flaw in the AudioShare 2.0.2 web application that exposes a dangerous path traversal and code execution vector. This vulnerability exists within the ajax/myajaxphp.php component and specifically targets the config['basedir'] parameter, which is improperly validated and sanitized before being used in file inclusion operations. The flaw allows remote attackers to inject malicious URLs that are then processed by the application, enabling arbitrary PHP code execution on the target server. This type of vulnerability falls under the category of CWE-88, which describes improper neutralization of special elements used in an OS command, and more specifically aligns with CWE-94, representing inadequate control of generation of code, commonly known as code injection. The vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, as it enables attackers to execute arbitrary commands through PHP code injection.
The technical implementation of this vulnerability exploits the lack of proper input validation and sanitization in the application's parameter handling. When the config['basedir'] parameter receives a URL value, the application fails to properly validate or sanitize this input before using it in a file inclusion context. This allows attackers to supply malicious URLs that point to remote servers hosting attacker-controlled PHP code. The vulnerability is particularly dangerous because it enables attackers to bypass normal access controls and execute arbitrary code with the privileges of the web server process. The remote file inclusion nature of this flaw means that attackers do not need to have local access to the system or knowledge of the file structure to exploit it, making it highly attractive to threat actors seeking to compromise web applications. The attack chain typically involves crafting a malicious URL that includes PHP code and then passing this URL as the config['basedir'] parameter to trigger the remote code execution.
The operational impact of CVE-2015-4726 extends beyond simple code execution to potentially compromise entire web server infrastructures and underlying systems. Successful exploitation can lead to complete system compromise, allowing attackers to establish persistent backdoors, exfiltrate sensitive data, and use the compromised server as a launchpad for further attacks within the network. The vulnerability affects not just the AudioShare application but also potentially exposes the entire hosting environment to unauthorized access. Organizations running affected versions of AudioShare face significant risk of data breaches, service disruption, and regulatory compliance violations. The impact is particularly severe for applications that handle sensitive user data or financial information, as the vulnerability could enable attackers to access confidential databases, user credentials, and other critical assets. The vulnerability also demonstrates poor security practices in input validation and parameter handling, indicating that other components of the application may be similarly vulnerable to injection attacks.
Mitigation strategies for CVE-2015-4726 require immediate action to address the root cause of the vulnerability through proper input validation and parameter sanitization. The primary remediation involves implementing strict input validation on the config['basedir'] parameter to ensure that only legitimate local file paths are accepted, rejecting any URLs or remote references. Organizations should implement whitelisting mechanisms that restrict file inclusion to predefined safe directories and reject any input that contains remote URL schemes. The application should also employ proper sanitization techniques to remove or encode any potentially dangerous characters from user-supplied input before processing. Additionally, the use of PHP's disable_functions directive can help limit the potential impact of code execution by disabling dangerous functions like eval, exec, and system. Security updates and patches should be applied immediately to the AudioShare application, with organizations implementing comprehensive input validation across all user-supplied parameters. Network-level protections such as web application firewalls can provide additional defense-in-depth by monitoring for suspicious URL patterns and blocking known malicious payloads. Regular security assessments and code reviews should be conducted to identify and remediate similar vulnerabilities in other application components, ensuring that the application follows secure coding practices and adheres to industry standards such as OWASP Top Ten and NIST cybersecurity guidelines.