CVE-2016-9681 in Serendipity
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Serendipity before 2.0.5 allow remote authenticated users to inject arbitrary web script or HTML via a category or directory name.
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Analysis
by VulDB Data Team • 10/12/2022
The vulnerability identified as CVE-2016-9681 represents a critical cross-site scripting flaw affecting the Serendipity content management system prior to version 2.0.5. This vulnerability exists within the application's handling of user-supplied input in category and directory name fields, creating a persistent security risk that can be exploited by authenticated attackers. The flaw allows malicious users with valid accounts to inject arbitrary web script or HTML code that gets executed in the context of other users' browsers when they view affected pages.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the Serendipity application's category and directory management components. When administrators or regular users create or modify categories and directories, the system fails to properly sanitize the input data before storing and rendering it in web pages. This failure creates an XSS vector where malicious payloads can be embedded in the name fields and subsequently executed whenever the affected content is displayed to other users. The vulnerability affects both authenticated users and the broader user base who interact with the content management system, making it particularly dangerous in multi-user environments where administrative privileges may be compromised.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, and redirection to malicious websites. An attacker with access to the system can craft specially formatted category or directory names that contain JavaScript payloads, which then execute in the browsers of other users who view the affected pages. This could lead to unauthorized access to sensitive data, modification of content, or even complete compromise of user sessions. The vulnerability is particularly concerning because it requires minimal privileges to exploit, as authenticated users can leverage their existing access to inject malicious code.
This vulnerability maps to CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') and aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript. The attack surface is broadened by the fact that the vulnerability affects multiple areas of the application where user input is processed and displayed without proper sanitization. Organizations using Serendipity versions prior to 2.0.5 face significant risk of persistent XSS attacks that can compromise user sessions and data integrity. The vulnerability demonstrates a fundamental flaw in the application's security architecture where input validation is not consistently applied across all user-facing data entry points.
Mitigation strategies should focus on immediate patching to version 2.0.5 or later, which includes proper input sanitization and output encoding mechanisms. Additionally, administrators should implement proper input validation at multiple levels including client-side and server-side filtering, and ensure that all user-supplied data is properly encoded before rendering in web contexts. Network-based security controls such as web application firewalls can provide additional protection layers, though they should not replace proper application-level fixes. Regular security audits and input validation testing should be implemented to prevent similar vulnerabilities from emerging in the future, as this type of flaw represents a common pattern in web application security that requires consistent attention to proper data handling practices.