CVE-2011-4903 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 RemoveXSS function.
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Analysis
by VulDB Data Team • 11/07/2019
The vulnerability CVE-2011-4903 represents a critical cross-site scripting flaw in the TYPO3 content management system that affected multiple version branches including 4.3.x, 4.4.x, and 4.5.x prior to their respective security patches. This vulnerability resides in the RemoveXSS function which was designed to sanitize user input and prevent malicious scripts from being executed within the web application. The flaw allows remote attackers to bypass the intended security measures and inject arbitrary web scripts or HTML code into the application's output, potentially compromising user sessions and data integrity.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the TYPO3 core's XSS protection mechanisms. When user-supplied data was processed through the RemoveXSS function, the sanitization logic failed to properly handle certain edge cases or specific character sequences that could be crafted to evade the filtering rules. This weakness falls under the CWE-79 category of Cross-Site Scripting, specifically representing a failure in input validation and output encoding. The vulnerability enables attackers to inject malicious payloads that execute in the context of other users' browsers, making it particularly dangerous for content management systems where multiple users interact with the platform.
The operational impact of CVE-2011-4903 extends beyond simple script injection attacks, as it can lead to session hijacking, credential theft, and the execution of arbitrary commands on affected systems. Attackers could exploit this vulnerability to steal cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. The attack surface is particularly large given that TYPO3 is widely used for enterprise content management and web applications, making this vulnerability attractive to threat actors seeking to compromise multiple organizations simultaneously. According to ATT&CK framework, this vulnerability maps to T1059.007 (Scripting) and T1566 (Phishing) techniques, as it enables both command execution through script injection and user deception via malicious content delivery.
Organizations affected by this vulnerability should immediately upgrade to the patched versions of TYPO3 4.3.12, 4.4.9, or 4.5.4, depending on their current version. Additionally, administrators should implement proper input validation at multiple layers of the application architecture, including both server-side and client-side sanitization. The recommended mitigations include deploying web application firewalls, implementing content security policies, and conducting regular security audits of input handling mechanisms. Security teams should also monitor for exploitation attempts through log analysis and network traffic inspection, as the vulnerability typically manifests through crafted HTTP requests containing malicious script payloads. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and maintain comprehensive vulnerability management programs to prevent similar issues in the future.