CVE-2018-16836 in Rubedo
Summary
by MITRE
Rubedo through 3.4.0 contains a Directory Traversal vulnerability in the theme component, allowing unauthenticated attackers to read and execute arbitrary files outside of the service root path, as demonstrated by a /theme/default/img/%2e%2e/..//etc/passwd URI.
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Analysis
by VulDB Data Team • 12/24/2024
The vulnerability CVE-2018-16836 represents a critical directory traversal flaw within the Rubedo content management system version 3.4.0 and earlier. This security weakness resides in the theme component of the application, specifically in how it processes URI requests containing encoded directory traversal sequences. The vulnerability allows unauthenticated attackers to bypass normal access controls and retrieve arbitrary files from the underlying file system, potentially exposing sensitive system information and enabling further exploitation. The attack vector is demonstrated through a specific URI pattern that leverages double dot sequences encoded as %2e%2e/..// to navigate beyond the intended service root path and access protected system files such as /etc/passwd.
The technical implementation of this vulnerability stems from inadequate input validation and path sanitization within the theme component's file access mechanisms. When processing requests containing directory traversal sequences, the application fails to properly sanitize user-supplied URI parameters before using them to construct file paths. This allows attackers to inject malicious path components that bypass normal file system access controls. The vulnerability specifically affects the theme module's handling of image resources, where the application does not adequately validate or normalize file paths before attempting to serve requested theme assets. The flaw enables attackers to craft requests that exploit the relative path resolution behavior of the web server to access files outside the intended web root directory.
The operational impact of this vulnerability is severe and multifaceted. An unauthenticated attacker can leverage this weakness to extract sensitive system information including password files, configuration files, and potentially database credentials. Beyond information disclosure, the vulnerability enables arbitrary code execution capabilities when combined with other attack vectors, as attackers can potentially upload and execute malicious files within the application's directory structure. This weakness significantly undermines the application's security posture and can lead to complete system compromise. The vulnerability affects organizations using Rubedo versions up to 3.4.0, potentially exposing their entire infrastructure to unauthorized access and data breaches.
Organizations should immediately implement mitigations including upgrading to Rubedo version 3.4.1 or later, which contains patches addressing this directory traversal vulnerability. Network-level protections such as web application firewalls should be configured to detect and block requests containing suspicious path traversal sequences. Input validation mechanisms should be strengthened to properly sanitize all user-supplied URI parameters before processing them within the application. Security teams should conduct comprehensive vulnerability assessments to identify any potential exploitation attempts and monitor system logs for suspicious activity related to theme component access. Additionally, implementing principle of least privilege access controls and regular security audits can help reduce the overall risk exposure. This vulnerability aligns with CWE-22 Directory Traversal and maps to ATT&CK technique T1059 Command and Scripting Interpreter, representing a critical threat that requires immediate attention and remediation to prevent unauthorized system access and data compromise.