CVE-2018-16975 in Elefant
Summary
by MITRE
An issue was discovered in Elefant CMS before 2.0.7. There is a PHP Code Execution Vulnerability in /designer/add/stylesheet.php by using a .php extension in the New Stylesheet Name field in conjunction with <?php content, because of insufficient input validation in apps/designer/handlers/csspreview.php.
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Analysis
by VulDB Data Team • 05/16/2023
This vulnerability exists within Elefant CMS versions prior to 2.0.7 and represents a critical php code execution flaw that allows remote attackers to execute arbitrary code on the affected system. The vulnerability is specifically located in the stylesheet management functionality where users can create new stylesheets through the designer module. The flaw occurs when an attacker provides a malicious filename containing a .php extension in the New Stylesheet Name field during the creation process.
The technical implementation of this vulnerability stems from inadequate input validation within the apps/designer/handlers/csspreview.php file which processes the stylesheet creation request. When a stylesheet name includes a .php extension, the system fails to properly sanitize this input, allowing the malicious file to be created with executable php code. The vulnerability is particularly dangerous because it leverages the <?php content syntax that enables php code execution directly within the stylesheet file, bypassing normal security controls that would typically prevent such code injection.
The operational impact of this vulnerability is severe as it provides attackers with complete control over the affected CMS instance. An attacker can execute arbitrary php commands, potentially leading to full system compromise, data exfiltration, or deployment of additional malicious payloads. This vulnerability affects the core functionality of the designer module and can be exploited by unauthenticated users, making it particularly dangerous in publicly accessible environments. The attack vector is straightforward requiring only access to the stylesheet creation interface and proper input formatting to achieve code execution.
The vulnerability aligns with CWE-94, which describes improper validation of the input, and relates to the broader category of code injection attacks that have been consistently identified as critical security flaws in web applications. From an attack framework perspective, this vulnerability maps to the execution phase of the attack lifecycle and could potentially be used to establish persistent access or escalate privileges within the compromised system. The flaw demonstrates poor input sanitization practices and highlights the importance of implementing proper validation controls for user-supplied data in web applications.
Mitigation strategies should include immediate patching to version 2.0.7 or later where the input validation has been properly implemented. Organizations should also implement additional defensive measures such as restricting access to the designer module, implementing web application firewalls, and conducting regular security audits of user input handling mechanisms. The fix should enforce strict validation of stylesheet names to prevent the inclusion of executable extensions and ensure that all user-supplied data is properly sanitized before being processed or stored within the system.