CVE-2012-3530 in TYPO3
Summary
by MITRE
Incomplete blacklist vulnerability in the t3lib_div::quoteJSvalue API function in TYPO3 4.5.x before 4.5.19, 4.6.x before 4.6.12 and 4.7.x before 4.7.4 allows remote attackers to conduct cross-site scripting (XSS) attacks via certain HTML5 JavaScript events.
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Analysis
by VulDB Data Team • 12/13/2021
The CVE-2012-3530 vulnerability represents a critical security flaw in the TYPO3 content management system that emerged from an incomplete blacklist implementation within the t3lib_div::quoteJSvalue API function. This vulnerability affected multiple versions of TYPO3 including 4.5.x before 4.5.19, 4.6.x before 4.6.12, and 4.7.x before 4.7.4, creating a significant attack surface for malicious actors seeking to exploit cross-site scripting vulnerabilities. The flaw specifically targeted the JavaScript escaping mechanism that was supposed to prevent malicious code execution in web applications.
The technical root cause of this vulnerability lies in the insufficient filtering of JavaScript event handlers within the quoteJSvalue function. When TYPO3 processed user input for JavaScript contexts, the system failed to properly sanitize HTML5 JavaScript events such as onclick, onmouseover, onfocus, and other DOM event handlers. This incomplete blacklist approach meant that certain dangerous event attributes could still pass through the sanitization process, allowing attackers to inject malicious JavaScript code into web pages. The vulnerability operates at the application layer and specifically affects how the CMS handles dynamic content rendering in JavaScript contexts, making it particularly dangerous for web applications that rely heavily on user-generated content.
The operational impact of CVE-2012-3530 extends beyond simple XSS attacks, as it provides attackers with the capability to execute arbitrary JavaScript code in the context of victim browsers. This vulnerability enables attackers to perform session hijacking, deface websites, steal sensitive user data, and potentially escalate privileges within the application. The attack vector is particularly insidious because it leverages legitimate HTML5 event attributes that are commonly used in web development, making the malicious code appear more benign to security systems. Attackers could craft payloads that would execute when users interacted with vulnerable pages, creating persistent XSS vulnerabilities that could affect multiple users over time.
The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and demonstrates how incomplete input validation can create security weaknesses. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for JavaScript execution and T1566 for social engineering techniques that could be employed to deliver malicious payloads. Organizations using affected TYPO3 versions faced significant risk of data breaches and reputation damage, as the vulnerability could be exploited through various means including malicious user registrations, comment submissions, or any input field that was processed through the vulnerable API function. The remediation process required immediate patching of affected systems and comprehensive security reviews of all JavaScript handling mechanisms within the application.
Organizations should implement multiple layers of defense including regular security updates, input validation improvements, and monitoring for suspicious JavaScript execution patterns. The vulnerability underscores the importance of proper security testing and the need for comprehensive sanitization approaches rather than relying solely on blacklist mechanisms. System administrators must ensure that all TYPO3 installations are updated to patched versions and that additional security controls such as content security policies are implemented to provide defense in depth against similar vulnerabilities.