CVE-2020-25119 in vBulletin
Summary
by MITRE
The Admin CP in vBulletin 5.6.3 allows XSS via a Title of a Child Help Item in the Login/Logoff part of the User Manual.
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Analysis
by VulDB Data Team • 09/04/2020
The vulnerability identified as CVE-2020-25119 represents a cross-site scripting flaw within the administrative control panel of vBulletin version 5.6.3. This issue specifically affects the handling of user manual content where administrators can create help items with child elements. The vulnerability occurs when a malicious actor crafts a Title field for a child help item within the Login/Logoff section of the user manual, embedding malicious script code that executes in the context of other users' browsers. The flaw exists in the input sanitization and output encoding mechanisms of the administrative interface, particularly when processing user-provided content for display in the help system. This vulnerability falls under CWE-79 which categorizes cross-site scripting as a critical weakness in web applications. The attack vector is particularly concerning because it operates within the administrative control panel, potentially allowing attackers to escalate privileges or execute unauthorized actions against the vBulletin installation.
The technical implementation of this vulnerability stems from inadequate validation of user input within the help item creation functionality. When administrators create child help items in the Login/Logoff section of the user manual, the system fails to properly sanitize the Title field against malicious script content. The vulnerability specifically manifests when the application renders the help item titles without adequate HTML escaping or context-appropriate encoding. The XSS occurs because the application assumes that user input from the administrative interface is safe for direct output to web pages, without implementing proper input validation or output encoding measures. This flaw demonstrates poor application security practices and violates fundamental security principles for handling untrusted input. The vulnerability aligns with ATT&CK technique T1213 which covers data from information repositories, particularly when the attack involves manipulating administrative interfaces to gain unauthorized access or execute malicious code.
The operational impact of this vulnerability extends beyond simple script execution as it provides potential attackers with a pathway for more sophisticated attacks. An attacker who can successfully exploit this vulnerability could execute malicious scripts that steal session cookies, redirect users to phishing sites, or perform unauthorized administrative actions. The attack requires an authenticated administrative session to exploit, but once achieved, it could enable attackers to compromise the entire vBulletin installation. The vulnerability affects the integrity and confidentiality of the application, potentially allowing for data exfiltration, unauthorized modifications to help documentation, or even complete system compromise if combined with other vulnerabilities. Organizations using vBulletin 5.6.3 should consider this vulnerability as a critical security risk, particularly in environments where administrative access is not properly restricted or where multiple administrators have access to the system. The vulnerability also represents a significant risk to user trust and application integrity, as malicious scripts could be executed against legitimate users who access the help system.
Mitigation strategies for CVE-2020-25119 should include immediate patching of the vBulletin installation to version 5.6.4 or later, which contains the necessary security fixes. Organizations should also implement additional security measures such as input validation and output encoding for all user-provided content within administrative interfaces. The principle of least privilege should be enforced for administrative accounts, ensuring that only necessary personnel have access to the help system management features. Regular security audits of administrative interfaces should be conducted to identify similar input validation issues. Network monitoring and intrusion detection systems should be configured to detect suspicious activity related to help system modifications. Organizations should also consider implementing web application firewalls to provide additional protection against XSS attacks. The fix addresses the root cause by implementing proper HTML escaping and input sanitization for help item titles, preventing malicious scripts from being executed when help content is rendered. This vulnerability highlights the importance of comprehensive security testing and the need for robust input validation in all user-facing administrative interfaces, particularly those that allow content creation and modification.