CVE-2012-2112 in TYPO3
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Exception Handler in TYPO3 4.4.x before 4.4.15, 4.5.x before 4.5.15, 4.6.x before 4.6.8, and 4.7 allows remote attackers to inject arbitrary web script or HTML via exception messages.
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Analysis
by VulDB Data Team • 12/12/2021
The CVE-2012-2112 vulnerability represents a critical cross-site scripting flaw within TYPO3 content management systems that affected multiple version branches including 4.4.x through 4.4.14, 4.5.x through 4.5.14, 4.6.x through 4.6.7, and 4.7.x. This vulnerability specifically resides in the Exception Handler component of the TYPO3 framework, which is responsible for managing and displaying error messages when system exceptions occur. The flaw stems from insufficient input validation and output encoding mechanisms that fail to properly sanitize exception messages before rendering them in web browsers. Attackers can exploit this weakness by crafting malicious input that triggers specific exception conditions, thereby injecting arbitrary HTML or JavaScript code into the error display pages.
The technical nature of this vulnerability aligns with CWE-79, which defines Cross-Site Scripting vulnerabilities as a result of inadequate sanitization of user-supplied data in web applications. When TYPO3 encounters an exception during processing, the system generates an error message containing information about the failure, including potentially user-provided data. In the vulnerable versions, this exception message content was not properly escaped or encoded before being rendered in the browser context. This allows attackers to inject malicious scripts that execute in the context of other users' browsers who view the exception page, creating a persistent XSS vector that can be leveraged for session hijacking, credential theft, or redirection to malicious sites.
The operational impact of CVE-2012-2112 extends beyond simple script injection as it fundamentally compromises the security boundaries of TYPO3 installations. When exploited, this vulnerability can enable attackers to manipulate the user experience of legitimate site visitors, potentially redirecting them to phishing sites or stealing session cookies. The attack surface is particularly concerning because exception handling occurs during normal application operation, making exploitation possible through routine user interactions such as form submissions, file uploads, or URL parameter manipulation. The vulnerability affects not just the frontend user experience but also the administrative backend, as exception messages may be displayed to administrators during system maintenance or debugging operations. This creates a significant risk for organizations relying on TYPO3 for mission-critical applications, as the vulnerability can be exploited without requiring authentication or privileged access.
Security practitioners should implement immediate mitigations including applying the official TYPO3 patches released for versions 4.4.15, 4.5.15, 4.6.8, and 4.7.0 respectively. Organizations should also consider implementing web application firewalls with XSS detection capabilities and comprehensive input validation policies. The vulnerability demonstrates the importance of secure error handling practices as outlined in the OWASP Top Ten and aligns with ATT&CK technique T1211 for lateral movement through web application vulnerabilities. Additionally, organizations should conduct regular security assessments of their TYPO3 installations and implement proper output encoding mechanisms throughout their applications to prevent similar vulnerabilities from emerging in other components of the system. The incident underscores the critical need for robust input sanitization and output encoding practices in all web application development, particularly in error handling and logging components where user-supplied data may be displayed without proper sanitization.