CVE-2017-14921 in Tine Community Edition
Summary
by MITRE
Stored XSS vulnerability via IMG element at "Filename" of Filemanager in Tine 2.0 Community Edition before 2017.08.4 allows an authenticated user to inject JavaScript, which is mishandled during rendering by the application administrator and other users.
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Analysis
by VulDB Data Team • 12/30/2022
The stored cross-site scripting vulnerability identified as CVE-2017-14921 affects the Tine 2.0 Community Edition file manager component prior to version 2017.08.4. This vulnerability resides within the handling of the "Filename" parameter when processing IMG elements, creating a persistent security flaw that can be exploited by authenticated users with access to the file management functionality. The vulnerability stems from inadequate input sanitization and output encoding mechanisms that fail to properly validate or escape user-supplied data before it is stored and subsequently rendered in the web interface. The flaw specifically manifests when users upload or modify file names containing malicious script code within the filename field, which then gets executed in the context of other users' browsers when they view or interact with the affected file entries.
The technical implementation of this vulnerability involves the manipulation of the filename parameter through an IMG element that is processed by the file manager's rendering engine. When an authenticated user creates or modifies a file entry with malicious JavaScript code embedded within the filename, the application stores this data without proper sanitization. Subsequently, when other users access the file manager interface and view the affected file entries, the stored malicious code executes within their browser context. This creates a persistent threat vector where attackers can establish a foothold within the application environment and potentially escalate privileges or extract sensitive information. The vulnerability directly maps to CWE-79 which describes Cross-site Scripting flaws, specifically the stored variant where malicious scripts are permanently stored on the target server and executed when accessed by other users.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, data exfiltration, and privilege escalation within the Tine 2.0 environment. Administrators who view the affected files in the file manager are particularly at risk since their elevated privileges make them prime targets for exploitation. The vulnerability can be leveraged to create backdoors, steal cookies, redirect users to malicious sites, or even execute arbitrary commands on the target system depending on the application's architecture and the attacker's level of access. Given that Tine 2.0 is a collaborative platform used for business applications, the compromise of a single authenticated user can potentially affect multiple users and departments within the organization. The attack vector is particularly dangerous because it requires minimal user interaction beyond normal file management operations, making detection and prevention more challenging.
Mitigation strategies for CVE-2017-14921 should focus on implementing robust input validation and output encoding mechanisms within the file manager component. Organizations should immediately upgrade to Tine 2.0 version 2017.08.4 or later, which includes patches addressing this vulnerability. Additionally, administrators should implement strict filename validation that rejects or sanitizes potentially malicious content including script tags, event handlers, and other XSS attack vectors. The application should enforce proper HTML escaping when rendering filenames in user interfaces, ensuring that any user-supplied content is treated as data rather than executable code. Network monitoring solutions should be configured to detect unusual file upload patterns or attempts to inject script code through filename fields. Implementing content security policies and using security headers can provide additional protection layers against exploitation attempts. Regular security audits of file management components and input validation mechanisms should be conducted to identify similar vulnerabilities in other parts of the application, as this flaw demonstrates the importance of proper sanitization throughout all user input handling processes. The vulnerability also highlights the need for comprehensive security training for developers working with web applications to prevent similar issues in future development cycles.