CVE-2015-2974 in PHP Gazou BBS Plus
Summary
by MITRE
LEMON-S PHP Gazou BBS plus before 2.36 allows remote attackers to upload arbitrary HTML documents via vectors involving a crafted image file.
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Analysis
by VulDB Data Team • 07/25/2017
The vulnerability identified as CVE-2015-2974 affects LEMON-S PHP Gazou BBS plus versions prior to 2.36, representing a critical security flaw that enables remote attackers to execute arbitrary code through malicious file uploads. This vulnerability stems from inadequate input validation and file type verification mechanisms within the application's upload functionality, creating a pathway for attackers to bypass security controls and deploy malicious content.
The technical implementation of this vulnerability involves a classic file upload vulnerability where attackers can manipulate the file extension and content of image files to include HTML or other executable code. The flaw occurs because the application fails to properly validate file types based on their actual content rather than relying solely on file extensions or MIME type headers. Attackers can craft image files that contain embedded HTML code, which gets processed and stored by the vulnerable application, potentially allowing for cross-site scripting attacks or server-side code execution. This weakness aligns with CWE-434, which specifically addresses the improper restriction of file uploads, and represents a common vector for web application attacks that can lead to full system compromise.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it provides attackers with persistent access to the target system through uploaded malicious content. Once successful, the vulnerability allows for ongoing exploitation through the uploaded HTML documents, which can be used to establish command and control channels, steal user credentials, or serve as a foothold for further network infiltration. The attack surface is particularly concerning because it affects web-based bulletin board systems that often store user-generated content, making the compromise of such systems a significant threat to organizations relying on these platforms for communication and collaboration.
Mitigation strategies for CVE-2015-2974 should prioritize immediate application patching to version 2.36 or later, which addresses the core file validation issues. Organizations should implement comprehensive file type validation that examines actual file content rather than relying on extensions or headers, using techniques such as file signature validation and content analysis. Additional defensive measures include restricting upload permissions, implementing proper file naming conventions, and deploying web application firewalls to monitor and filter suspicious upload activities. The vulnerability demonstrates the importance of adhering to security best practices outlined in the OWASP Top Ten, particularly the prevention of insecure file uploads and the implementation of proper input validation mechanisms. This weakness also aligns with ATT&CK technique T1190, which covers the exploitation of vulnerabilities in web applications through malicious file uploads, emphasizing the need for layered security approaches that include both application-level defenses and network monitoring capabilities to detect and prevent such attacks.