CVE-2013-5353 in Sharetronix
Summary
by MITRE
Unrestricted file upload vulnerability in system/controllers/ajax/attachments.php in Sharetronix 3.1.1.3, 3.1.1, and earlier allows remote attackers to execute arbitrary code by uploading a file with an executable extension, then accessing it via a direct request to the file in an unspecified directory.
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Analysis
by VulDB Data Team • 03/10/2019
The vulnerability identified as CVE-2013-5353 represents a critical unrestricted file upload flaw within the Sharetronix content management system version 3.1.1.3 and earlier releases. This vulnerability exists in the file system/controllers/ajax/attachments.php component which handles file upload operations through ajax requests. The flaw allows remote attackers to bypass normal file validation mechanisms and upload malicious files with executable extensions such as .php, .asp, or .jsp directly to the web server. The vulnerability stems from inadequate input validation and sanitization of file uploads, creating a path for attackers to place malicious code on the target system.
The technical exploitation of this vulnerability involves uploading a specially crafted file containing malicious code with an extension that will be interpreted by the web server as executable. Once uploaded, the attacker can access the file directly through a web request to the file location in an unspecified directory, enabling arbitrary code execution on the target system. This type of vulnerability falls under CWE-434 which specifically addresses Unrestricted Upload of File with Dangerous Type, and represents a fundamental flaw in the application's security architecture where file upload validation is insufficient to prevent the execution of malicious payloads. The vulnerability creates a persistent backdoor that can be leveraged for further attacks and system compromise.
The operational impact of this vulnerability is severe and far-reaching for any organization running affected Sharetronix installations. Remote code execution capabilities allow attackers to gain full control over the affected web server, potentially leading to complete system compromise, data exfiltration, and establishment of persistent access points. The vulnerability can be exploited without authentication, making it particularly dangerous as it can be targeted by automated scanning tools and malicious actors seeking to compromise web applications. This vulnerability aligns with ATT&CK technique T1190 which describes the use of exploits for code execution, and T1078 which covers legitimate credentials usage for persistence.
Mitigation strategies for CVE-2013-5353 require immediate remediation through patching the affected Sharetronix versions to the latest releases that address the file upload validation issues. Organizations should implement strict file type validation that rejects executable extensions and enforces proper file content checking rather than relying solely on extension-based filtering. Additional defensive measures include implementing secure file upload practices such as storing uploaded files outside the web root directory, using random file names, and implementing proper access controls. The vulnerability demonstrates the critical importance of input validation and the principle of least privilege in web application security, as recommended by OWASP Top Ten and NIST cybersecurity frameworks. Regular security assessments and web application firewalls should be deployed to monitor and prevent exploitation attempts.