CVE-2018-18745 in SEMCMS
Summary
by MITRE
An XSS issue was discovered in SEMCMS 3.4 via admin/SEMCMS_Menu.php?lgid=1 during editing.
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Analysis
by VulDB Data Team • 04/07/2020
The vulnerability identified as CVE-2018-18745 represents a cross-site scripting flaw within SEMCMS version 3.4 that specifically affects the administrative interface. This issue manifests in the SEMCMS_Menu.php script when processing the lgid parameter during content editing operations, creating a persistent security weakness that could be exploited by malicious actors to execute arbitrary code within the context of authenticated admin sessions. The vulnerability resides in the improper sanitization of user-supplied input that flows directly into the web application's output without adequate validation or encoding mechanisms.
This XSS vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is a critical security weakness that allows attackers to inject malicious scripts into web pages viewed by other users. The specific nature of this flaw in SEMCMS demonstrates how parameter manipulation can lead to unauthorized code execution, particularly within administrative interfaces where elevated privileges exist. The lgid parameter serves as the attack vector, where an attacker can inject malicious JavaScript code that will execute whenever the affected page is rendered to an administrator or authenticated user. The vulnerability is classified as a reflected XSS issue since the malicious payload is processed and reflected back to the user's browser through the application's response to the manipulated parameter.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the capability to escalate privileges and potentially gain complete control over the CMS administration interface. When an administrator views the affected page, their browser executes the injected JavaScript code, which could steal session cookies, redirect users to malicious sites, or perform unauthorized actions within the CMS. This type of vulnerability enables attackers to establish persistent access to the administrative environment, potentially leading to full system compromise. The attack surface is particularly concerning given that it targets the administrative editing functionality, which typically requires elevated privileges and contains sensitive configuration data.
Mitigation strategies for CVE-2018-18745 should focus on implementing robust input validation and output encoding mechanisms throughout the SEMCMS application. The most effective immediate solution involves sanitizing all user-supplied input parameters, particularly those used in dynamic content generation, through proper HTML escaping and validation routines. Organizations should implement Content Security Policy headers to prevent unauthorized script execution, while also ensuring that all user inputs undergo strict validation before being processed or stored. The vulnerability aligns with ATT&CK technique T1213 which involves data from information repositories, and represents a critical entry point for attackers seeking to establish persistent access to web applications. Regular security audits and input validation testing should be conducted to prevent similar vulnerabilities from emerging in other parts of the application. Additionally, implementing proper access controls and monitoring for unusual administrative activities can help detect exploitation attempts and limit potential damage from successful attacks.