CVE-2009-3633 in TYPO3
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the t3lib_div::quoteJSvalue API function in TYPO3 4.0.13 and earlier, 4.1.x before 4.1.13, 4.2.x before 4.2.10, and 4.3.x before 4.3beta2 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors related to the sanitizing algorithm.
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Analysis
by VulDB Data Team • 02/16/2025
The CVE-2009-3633 vulnerability represents a critical cross-site scripting flaw within the TYPO3 content management system that affects multiple version ranges including 4.0.13 and earlier, 4.1.x before 4.1.13, 4.2.x before 4.2.10, and 4.3.x before 4.3beta2. This vulnerability specifically targets the t3lib_div::quoteJSvalue API function which serves as a critical component for sanitizing JavaScript values in web applications. The flaw stems from an insufficient sanitization algorithm that fails to properly handle malicious input, creating an exploitable condition where attackers can inject arbitrary web scripts or HTML content. The vulnerability operates at the application layer and specifically impacts the JavaScript escaping mechanisms that TYPO3 employs to prevent XSS attacks, making it particularly dangerous for web applications that rely heavily on dynamic content generation and user input handling.
The technical exploitation of this vulnerability occurs through the improper handling of input data within the quoteJSvalue function, which is designed to escape JavaScript strings for safe inclusion in web pages. When users submit content or when the application processes data that gets rendered in JavaScript contexts, the flawed sanitization algorithm fails to adequately escape special characters and control sequences that could be interpreted as executable JavaScript code. This allows attackers to inject malicious payloads that execute in the context of other users' browsers when they view affected pages. The vulnerability is classified under CWE-79 as a Cross-Site Scripting flaw and aligns with ATT&CK technique T1189 which involves the exploitation of application vulnerabilities to execute malicious code in user browsers. The issue particularly affects the application's ability to properly sanitize data when it transitions from server-side processing to client-side execution, creating a persistent security gap in the data flow.
The operational impact of CVE-2009-3633 extends beyond simple script injection to potentially enable more sophisticated attacks including session hijacking, credential theft, and redirection to malicious sites. Attackers could leverage this vulnerability to establish persistent backdoors within affected web applications, particularly in environments where users have administrative privileges or where sensitive data is processed. The vulnerability affects the core functionality of TYPO3's security model and could compromise the integrity of entire web applications that depend on proper input sanitization. Organizations using affected TYPO3 versions face significant risk of data breaches and unauthorized access, as the vulnerability allows for arbitrary code execution in user browsers. The flaw particularly impacts web applications that process user-generated content or that rely on JavaScript for dynamic interface elements, making it a critical concern for content management systems and web applications in general. The vulnerability demonstrates the importance of robust input validation and proper escaping mechanisms in preventing client-side attacks.
Mitigation strategies for CVE-2009-3633 require immediate patching of affected TYPO3 installations to versions that contain the corrected sanitization algorithm. Organizations should implement comprehensive security updates and ensure that all instances of the affected software are upgraded to patched versions. Additionally, administrators should consider implementing additional security measures such as content security policies, input validation at multiple layers, and regular security assessments to identify potential vulnerabilities. The fix addresses the root cause by improving the sanitization algorithm within the quoteJSvalue function, ensuring that all special characters and control sequences are properly escaped before being rendered in JavaScript contexts. Security teams should also conduct thorough vulnerability assessments to identify any other potential XSS vulnerabilities in their web applications and ensure that proper security controls are in place. The remediation process should include comprehensive testing to verify that the patched version properly handles all input scenarios and that no regressions have been introduced in the application's functionality.