CVE-2011-4626 in TYPO3
Summary
by MITRE
Cross-site Scripting (XSS) in TYPO3 before 4.3.12, 4.4.x before 4.4.9, and 4.5.x before 4.5.4 allows remote attackers to inject arbitrary web script or HTML via the "JSwindow" property of the typolink function.
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Analysis
by VulDB Data Team • 11/07/2019
The vulnerability CVE-2011-4626 represents a critical cross-site scripting flaw in the TYPO3 content management system that affected multiple version branches including 4.3.12, 4.4.9, and 4.5.4. This vulnerability resides in the typolink function's JSwindow property handling mechanism, which is a core component used for creating hyperlinks within the TYPO3 framework. The flaw enables remote attackers to inject malicious JavaScript code or HTML content that gets executed in the context of other users' browsers when they visit pages containing the vulnerable links. This represents a classic XSS attack vector that can be exploited to compromise user sessions, steal sensitive information, or redirect users to malicious websites. The vulnerability is particularly concerning because it affects the core linking functionality that is extensively used throughout TYPO3 websites, making it a widespread potential attack surface.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the typolink function's JSwindow parameter processing. When developers or content editors use the typolink function with the JSwindow property, the system should properly sanitize and encode any user-supplied parameters before incorporating them into the generated HTML output. However, the vulnerability exists because the system fails to adequately escape special characters and script tags in the JSwindow parameter, allowing attackers to inject malicious payloads that are then executed by the victim's browser. This flaw aligns with CWE-79, which specifically addresses Cross-site Scripting vulnerabilities in web applications, and demonstrates a failure in proper input sanitization and output encoding practices. The vulnerability specifically impacts the application's ability to properly handle user-controllable data within its hyperlink generation system, creating a persistent security weakness that can be exploited across various TYPO3 installations.
The operational impact of CVE-2011-4626 extends beyond simple script injection, as it provides attackers with significant capabilities to manipulate user experiences and extract sensitive data from authenticated sessions. When exploited, this vulnerability can enable attackers to steal cookies, session tokens, and other sensitive information that users might have in their browsers. The attack can be particularly devastating in environments where TYPO3 is used for corporate or government websites, as it could allow unauthorized access to administrative interfaces or sensitive content management systems. Additionally, attackers can use this vulnerability to redirect users to phishing sites or to inject malicious advertisements into legitimate websites. The vulnerability's presence in multiple version branches means that a large number of TYPO3 installations were potentially exposed, creating a widespread security risk that required immediate attention and patching. According to ATT&CK framework, this vulnerability maps to T1059.007 for script injection techniques and T1566 for credential access through social engineering, as attackers could leverage the XSS to harvest user credentials.
Mitigation strategies for CVE-2011-4626 focus primarily on immediate patching and application hardening measures. Organizations should immediately upgrade to the patched versions of TYPO3 (4.3.12, 4.4.9, or 4.5.4) that contain proper input validation and output encoding for the JSwindow parameter. System administrators should also implement comprehensive input validation at multiple layers, including application-level sanitization and content security policy enforcement. The implementation of proper output encoding for all user-controllable parameters within the typolink function helps prevent malicious scripts from being executed. Additional defensive measures include monitoring web application logs for suspicious requests containing script tags or unusual parameter values, implementing web application firewalls with XSS detection capabilities, and conducting regular security assessments of TYPO3 installations. Security teams should also consider implementing CSP headers to limit the execution of inline scripts and restrict the sources from which scripts can be loaded. Organizations that cannot immediately patch should consider implementing temporary workarounds such as disabling the affected typolink functionality or implementing strict input filtering rules for the JSwindow parameter to prevent exploitation while maintaining system functionality.