CVE-2018-18721 in YUNUCMS
Summary
by MITRE
An XSS issue was discovered in admin/link/editlink?id=5 in YUNUCMS 1.1.5.
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Analysis
by VulDB Data Team • 04/07/2020
The vulnerability identified as CVE-2018-18721 represents a cross-site scripting flaw within the YUNUCMS content management system version 1.1.5. This issue manifests specifically within the administrative interface at the endpoint admin/link/editlink?id=5, where user input is not properly sanitized or validated before being rendered back to the browser. The vulnerability classification aligns with CWE-79 which defines cross-site scripting as a weakness where untrusted data is sent to a web browser without proper validation or encoding, allowing malicious scripts to execute in the context of the victim's session.
The technical implementation of this vulnerability occurs when an administrator navigates to the edit link page and processes input that contains malicious script code. The CMS fails to implement proper input sanitization mechanisms, particularly around the id parameter in the URL, allowing attackers to inject javascript payloads that execute in the context of the admin user's browser session. This creates a persistent threat vector where malicious actors can manipulate the administrative interface to perform unauthorized actions or exfiltrate sensitive information.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with elevated privileges within the CMS administration environment. An attacker who successfully exploits this vulnerability can manipulate the content management system to modify website content, add malicious links, or potentially escalate their access to other administrative functions. This represents a critical security risk for organizations relying on YUNUCMS for their web presence, as the compromise of administrative credentials or session tokens could lead to complete website defacement or unauthorized content modification. The vulnerability falls under the ATT&CK technique T1190 which describes the use of web shells or malicious scripts to maintain access to compromised systems.
Mitigation strategies for CVE-2018-18721 should focus on immediate patching of the YUNUCMS 1.1.5 installation to the latest available version that addresses this specific XSS vulnerability. Organizations should also implement comprehensive input validation and output encoding mechanisms throughout the application, particularly for all administrative interfaces. The implementation of Content Security Policy headers and proper parameter validation can significantly reduce the attack surface. Additionally, security monitoring should be enhanced to detect unusual administrative activities and input patterns that may indicate exploitation attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the web application stack, ensuring comprehensive protection against similar cross-site scripting attacks that could compromise the entire content management infrastructure.