CVE-2017-11405 in CMS Made Simple
Summary
by MITRE
In CMS Made Simple (CMSMS) 2.2.2, remote authenticated administrators can upload a .php file via a CMSContentManager action to admin/moduleinterface.php, followed by a FilePicker action to admin/moduleinterface.php in which type=image is changed to type=file.
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Analysis
by VulDB Data Team • 10/26/2019
The vulnerability identified as CVE-2017-11405 represents a critical file upload flaw in CMS Made Simple version 2.2.2 that allows authenticated administrators to achieve arbitrary code execution through a carefully crafted sequence of administrative actions. This vulnerability falls under the CWE-434 category of Unrestricted Upload of File with Dangerous Type, which is a well-documented weakness that enables attackers to upload malicious files that can execute arbitrary code on the target system. The flaw specifically resides in the CMSContentManager module's handling of file uploads within the admin/moduleinterface.php endpoint, creating a pathway for privilege escalation and potential system compromise.
The technical exploitation of this vulnerability requires an authenticated administrator account, which significantly reduces the attack surface but does not eliminate the risk entirely. Attackers can initiate the malicious upload process by first utilizing the CMSContentManager action to navigate to the admin/moduleinterface.php endpoint, then executing a FilePicker action where the type parameter is manipulated from image to file. This parameter manipulation allows the system to accept and process PHP files as legitimate uploads, bypassing normal file type validation mechanisms that should prevent execution of potentially harmful code. The vulnerability is particularly dangerous because it leverages legitimate administrative functionality to achieve unauthorized code execution, making detection more challenging and the attack more convincing to security monitoring systems.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to establish persistent access to the compromised system. Once a malicious PHP file is successfully uploaded, it can be executed to create backdoors, establish command and control channels, or perform further reconnaissance activities within the network. The vulnerability affects the integrity and confidentiality of the entire CMS platform, potentially exposing sensitive user data, administrative credentials, and other critical information stored within the system. Organizations using CMS Made Simple 2.2.2 are at risk of complete system compromise, data breaches, and potential lateral movement within their network infrastructure. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically targeting PHP execution, and represents a significant threat to the overall security posture of affected systems.
The recommended mitigation strategies for this vulnerability include immediate patching of CMS Made Simple to version 2.2.3 or later, which contains the necessary fixes to prevent unauthorized file uploads. Organizations should also implement additional security controls such as restricting administrative access to trusted networks, implementing strict file type validation at multiple layers, and conducting regular security audits of administrative interfaces. Network segmentation and monitoring of administrative endpoints can help detect suspicious upload activities, while regular penetration testing and vulnerability scanning should be performed to identify similar issues within the application stack. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in administrative interfaces, as it highlights how legitimate administrative functionality can be abused when proper security controls are not in place to prevent unauthorized code execution.