CVE-2020-18445 in yunucms
Summary
by MITRE • 08/12/2021
Cross Site Scripting (XSS) vulnerability exists in YUNUCMS 1.1.9 via the upurl function in Page.php.
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Analysis
by VulDB Data Team • 08/17/2021
The vulnerability CVE-2020-18445 represents a cross site scripting flaw identified in YUNUCMS version 1.1.9, specifically within the upurl function of the Page.php file. This type of vulnerability falls under the CWE-79 category, which defines cross site scripting as a code injection attack that enables attackers to execute scripts in the victim's browser. The flaw manifests when the application fails to properly sanitize user input before processing it through the upurl function, creating an avenue for malicious code execution.
The technical implementation of this vulnerability occurs within the Page.php file where the upurl function handles URL processing without adequate input validation or output encoding. When users provide malicious input through URL parameters or form fields that are then processed by this function, the application fails to escape special characters that could be interpreted as HTML or JavaScript code. This weakness allows attackers to inject malicious scripts that execute in the context of other users' browsers, potentially leading to session hijacking, data theft, or unauthorized actions performed on behalf of victims.
The operational impact of this vulnerability extends beyond simple script execution as it can enable sophisticated attack chains within web applications. Attackers can leverage this XSS flaw to steal session cookies, redirect users to malicious sites, modify web page content, or even perform actions that appear to originate from legitimate users. The attack surface is particularly concerning given that CMS platforms like YUNUCMS often serve as central management interfaces for websites, making successful exploitation potentially devastating for organizations relying on these systems. According to ATT&CK framework, this vulnerability maps to T1059.007 for scripting and T1531 for credential access through web application attacks.
Mitigation strategies for CVE-2020-18445 require immediate implementation of proper input sanitization and output encoding mechanisms throughout the application. The primary fix involves ensuring that all user-supplied data passed to the upurl function undergoes strict validation and sanitization before being processed or displayed. This includes implementing proper HTML entity encoding for any data that will be rendered in web pages, as well as employing Content Security Policy headers to limit script execution. Organizations should also consider implementing a web application firewall to detect and block suspicious input patterns, while regular security audits and code reviews should be conducted to identify similar vulnerabilities in other application components. The remediation process must align with OWASP Top Ten security practices, particularly focusing on input validation and output encoding controls to prevent similar injection attacks across the entire application stack.