CVE-2018-20476 in S-Cms
Summary
by MITRE
An issue was discovered in S-CMS 3.0. It allows XSS via the admin/demo.php T_id parameter.
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Analysis
by VulDB Data Team • 04/24/2020
The vulnerability identified as CVE-2018-20476 represents a cross-site scripting flaw within S-CMS version 3.0, specifically affecting the admin/demo.php component. This issue arises from insufficient input validation and output sanitization mechanisms that fail to properly handle user-supplied data. The vulnerability manifests through the T_id parameter which is processed without adequate security controls, creating an avenue for malicious actors to inject arbitrary script code into the application's response. Such flaws typically occur when applications fail to properly escape or encode data before rendering it in web pages, allowing attackers to execute scripts in the context of other users' browsers.
The technical exploitation of this vulnerability follows standard XSS attack patterns where an attacker crafts malicious input containing script code within the T_id parameter of the demo.php endpoint. When the vulnerable application processes this parameter and displays it without proper sanitization, the injected scripts execute in the victim's browser context. This can lead to session hijacking, credential theft, or redirection to malicious sites. The vulnerability aligns with CWE-79 which categorizes cross-site scripting as a critical weakness in web applications, specifically addressing the failure to sanitize user inputs that are subsequently reflected in web pages.
From an operational perspective, this vulnerability poses significant risks to administrative systems and can be leveraged to gain unauthorized access to sensitive administrative functions. The impact extends beyond simple script execution as attackers can potentially escalate privileges, manipulate data, or establish persistent access through session manipulation techniques. The vulnerability affects the core administrative functionality of S-CMS, making it particularly dangerous as it can be exploited by both authenticated and unauthenticated attackers depending on the application's configuration. This weakness can be classified under ATT&CK technique T1059.007 for scripting and T1566 for phishing, as it enables attackers to deliver malicious payloads through web-based interfaces.
The recommended mitigation strategies include implementing comprehensive input validation and output encoding mechanisms throughout the application. All user-supplied inputs must be properly sanitized and validated before processing, with special attention to parameters like T_id in this case. The application should employ context-appropriate output encoding for all dynamic content, particularly when rendering data within HTML contexts. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against XSS attacks by restricting script execution. Regular security testing including dynamic application security testing and manual penetration testing should be conducted to identify similar vulnerabilities. The fix should involve proper parameter validation and sanitization as outlined in OWASP Top 10 security guidelines, specifically addressing the prevention of cross-site scripting vulnerabilities through secure coding practices and input validation controls.