CVE-2015-7571 in Yaeger
Summary
by MITRE
Unrestricted file upload vulnerability in Yeager CMS 1.2.1 allows remote attackers to execute arbitrary code by uploading a file with an executable extension.
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Analysis
by VulDB Data Team • 03/29/2025
The CVE-2015-7571 vulnerability represents a critical unrestricted file upload flaw in Yeager CMS version 1.2.1 that exposes systems to remote code execution attacks. This vulnerability falls under the broader category of insecure file upload mechanisms that have been consistently identified as high-risk security issues in web applications. The flaw enables remote attackers to bypass normal file validation controls by uploading malicious files with executable extensions, creating a direct pathway for arbitrary code execution on the target server. The vulnerability demonstrates a fundamental failure in input validation and file handling processes within the content management system, where the application does not properly verify or sanitize file uploads before storing them on the server filesystem.
The technical exploitation of this vulnerability occurs when an attacker uploads a file containing malicious code with an extension that the CMS accepts without proper validation. This typically involves uploading files with extensions such as .php, .asp, .jsp, or other server-side script extensions that can be executed by the web server. The vulnerability stems from inadequate server-side validation mechanisms that fail to properly inspect file content, MIME types, or file extensions against a comprehensive whitelist of allowed formats. Attackers can leverage this weakness to upload web shells, malicious scripts, or other executable payloads that persist on the server and provide ongoing access to compromised systems. This flaw directly maps to CWE-434 Unrestricted Upload of File with Dangerous Type, which is categorized under the CWE top 25 most dangerous software weaknesses and is frequently referenced in security frameworks such as the OWASP Top Ten.
The operational impact of CVE-2015-7571 extends far beyond simple code execution, as it provides attackers with persistent access to compromised servers and potentially allows for complete system takeover. Once an attacker successfully uploads a malicious file, they can execute commands with the privileges of the web server process, which typically runs with elevated permissions on the hosting environment. This vulnerability creates a persistent backdoor that can be used for data exfiltration, lateral movement within networks, and establishment of command and control channels. The attack surface is particularly concerning because it affects the core functionality of content management systems that are widely deployed across organizations, making this vulnerability a prime target for automated scanning and exploitation campaigns. The vulnerability also enables attackers to establish persistence by uploading files that can survive server restarts and maintain access to the compromised environment over extended periods.
Mitigation strategies for CVE-2015-7571 must address both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities from occurring in the future. Organizations should implement strict file type validation by maintaining comprehensive whitelists of allowed file extensions and MIME types, while rejecting all other uploads. Server-side validation should include content-based verification to ensure that uploaded files match their declared extensions, preventing attackers from exploiting the vulnerability through file name manipulation or content spoofing techniques. The system should separate uploaded files from executable code directories and implement proper file permissions that prevent uploaded files from being executed directly. Additionally, organizations should employ multiple layers of security including web application firewalls, regular security assessments, and monitoring systems to detect unauthorized file uploads. This vulnerability aligns with ATT&CK technique T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, demonstrating how such flaws enable attackers to achieve persistent access and execute malicious commands within compromised environments. Regular security updates and patch management processes are essential to prevent exploitation of known vulnerabilities in widely deployed content management systems, as this particular flaw has been documented and addressed in subsequent versions of the Yeager CMS platform.