CVE-2018-16820 in Monstra
Summary
by MITRE
admin/index.php in Monstra CMS 3.0.4 allows arbitrary directory listing via id=filesmanager&path=uploads/.......//./.......//./ requests.
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Analysis
by VulDB Data Team • 05/17/2023
The vulnerability identified as CVE-2018-16820 affects Monstra CMS version 3.0.4 and represents a critical directory traversal flaw in the admin/index.php file. This issue enables authenticated attackers to enumerate arbitrary directories on the web server through crafted path parameters, specifically leveraging the filesmanager functionality with malicious path constructs. The vulnerability stems from insufficient input validation and sanitization within the file management component, allowing attackers to bypass normal access controls and potentially discover sensitive files or directories that should remain protected.
The technical exploitation of this vulnerability occurs through the manipulation of the path parameter in the filesmanager module, where attackers can construct path traversal sequences using multiple forward slashes and dot-separator combinations. The specific attack pattern involves sequences like uploads/.......//./.......//./ which, when processed by the CMS, can traverse beyond the intended upload directory boundaries. This type of vulnerability falls under CWE-22 - Improper Limitation of a Pathname to a Restricted Directory, which is a well-documented weakness in web applications where file system access is not properly restricted. The flaw demonstrates inadequate path normalization and validation mechanisms that fail to properly sanitize user-supplied input before processing file system operations.
The operational impact of this vulnerability extends beyond simple directory enumeration as it provides attackers with potential access to sensitive system information, configuration files, and potentially other web application components that may contain credentials or other exploitable data. An authenticated attacker with access to the admin interface can leverage this flaw to discover additional attack vectors, including system files, backup archives, or other sensitive directories that may contain database credentials, application secrets, or other confidential information. This vulnerability represents a significant risk to organizations using Monstra CMS, as it can be exploited to gain unauthorized access to system resources that should remain protected from user access. The flaw particularly affects the principle of least privilege by allowing unauthorized directory access that violates the intended security boundaries of the application's file system access controls.
Security mitigations for this vulnerability should focus on implementing robust input validation and sanitization mechanisms within the file management components of Monstra CMS. Organizations should immediately apply the vendor-provided patch or upgrade to a patched version of the CMS to address this directory traversal vulnerability. Additionally, implementing proper path normalization techniques that strip or reject malicious path sequences before processing file system operations will significantly reduce the risk of exploitation. Network-level protections such as web application firewalls can provide additional defense-in-depth measures by detecting and blocking suspicious path traversal patterns. The remediation should also include restricting file system access permissions for the web application to ensure that even if exploitation occurs, the attacker's access is limited to only the necessary application directories. This vulnerability highlights the importance of following secure coding practices and adhering to the principle of least privilege in web application development, particularly when handling file system operations and user-supplied input. Organizations should also implement monitoring and logging of file system access patterns to detect potential exploitation attempts and maintain compliance with security standards such as those outlined in the OWASP Top Ten and NIST cybersecurity frameworks.