CVE-2012-6509 in Car Portal
Summary
by MITRE
Unrestricted file upload vulnerability in NetArt Media Car Portal 3.0 allows remote attackers to execute arbitrary PHP code by uploading a file a double extension, as demonstrated by .php%00.jpg.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability identified as CVE-2012-6509 represents a critical unrestricted file upload flaw within NetArt Media Car Portal version 3.0, which enables remote attackers to execute arbitrary PHP code on the target system. This vulnerability stems from inadequate input validation and sanitization mechanisms within the file upload functionality, creating a pathway for malicious actors to bypass security controls and deploy malicious payloads. The specific exploitation technique involves uploading files with double extensions, where the filename contains both a legitimate extension and a malicious PHP extension separated by a null byte character, exemplified by the payload .php%00.jpg.
The technical implementation of this vulnerability occurs at the application layer where the system fails to properly validate file extensions and content types during the upload process. When a user uploads a file with a double extension such as .php%00.jpg, the application processes the file based on the first extension (.jpg) while ignoring the malicious PHP component that follows the null byte. This behavior exploits a common weakness in file validation systems where applications do not properly handle null byte characters or perform insufficient checks on file content. The vulnerability aligns with CWE-434 which specifically addresses the issue of unrestricted file upload, and it demonstrates how improper input validation can lead to code execution. The null byte handling issue also relates to CWE-174 which deals with weaknesses in input validation, particularly around improper handling of special characters in file names.
From an operational perspective, this vulnerability presents a severe risk to the confidentiality, integrity, and availability of the affected system. An attacker who successfully exploits this vulnerability can achieve remote code execution, allowing them to upload and execute malicious scripts that can compromise the entire web server. The impact extends beyond simple file upload manipulation as it can lead to complete system compromise, data theft, and potential lateral movement within the network. The vulnerability affects not only the immediate application but also poses risks to the underlying infrastructure, as successful exploitation can result in persistent backdoors, data exfiltration, and potential use as a launchpad for further attacks. The attack surface is particularly concerning given that this vulnerability can be exploited remotely without authentication, making it accessible to any internet-connected attacker.
The mitigation strategies for CVE-2012-6509 require a multi-layered approach focusing on both immediate remediation and long-term security hardening. Organizations should implement strict file validation mechanisms that reject files with double extensions or special characters including null bytes, while also validating file content rather than relying solely on extensions. The application should employ proper file type checking, content analysis, and sanitization processes that ensure uploaded files conform to expected formats and do not contain executable code. Additionally, implementing proper file storage practices such as storing uploaded files outside the web root directory and using randomized file names can significantly reduce the impact of successful exploitation attempts. Security controls should also include regular security assessments and penetration testing to identify similar vulnerabilities in the application. This vulnerability exemplifies the importance of following the principle of least privilege and implementing defense-in-depth strategies as outlined in the MITRE ATT&CK framework, where the exploitation of such vulnerabilities can lead to initial access and privilege escalation within the target environment. Organizations should also ensure that the affected application is updated to the latest version or patched according to vendor advisories to prevent exploitation of this known vulnerability.