CVE-2015-8757 in TYPO3
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Extension Manager in TYPO3 6.2.x before 6.2.16 and 7.x before 7.6.1 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors related to extension data during an extension installation.
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Analysis
by VulDB Data Team • 07/02/2022
The CVE-2015-8757 vulnerability represents a critical cross-site scripting flaw within TYPO3's Extension Manager component that affects versions 6.2.x prior to 6.2.16 and 7.x prior to 7.6.1. This vulnerability resides in the extension installation process where user-supplied data is not properly sanitized before being rendered in the web interface. The flaw enables remote attackers to inject malicious scripts or HTML code through unspecified vectors related to extension metadata during installation operations, creating a persistent security risk for TYPO3 installations. The vulnerability demonstrates a classic XSS weakness that can be exploited to execute arbitrary code within the context of a victim's browser session, potentially leading to complete compromise of user sessions and sensitive data exposure.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the Extension Manager's data handling mechanisms. When administrators install or update extensions through the TYPO3 interface, the system processes extension metadata including descriptions, author information, and other descriptive fields without proper sanitization of potentially malicious content. This failure to validate and encode user-provided data creates an attack surface where malicious actors can craft extension packages containing XSS payloads that execute when the extension information is displayed in the management interface. The vulnerability operates under CWE-79 which specifically addresses Cross-Site Scripting flaws in software applications, making it a direct manifestation of this well-known weakness category.
The operational impact of CVE-2015-8757 extends beyond simple script injection as it provides attackers with persistent access to administrative interfaces and user sessions. When administrators view extension information in the TYPO3 backend, the malicious scripts execute within their browser context, potentially allowing attackers to steal session cookies, modify extension configurations, or even escalate privileges within the TYPO3 system. The vulnerability is particularly dangerous because it targets the administrative interface where users have elevated permissions, making it a prime vector for privilege escalation attacks. Attackers can leverage this vulnerability to establish persistent backdoors, modify website content, or exfiltrate sensitive data from the TYPO3 installation.
Security professionals should implement multiple layers of defense to mitigate this vulnerability effectively. The primary recommendation involves upgrading affected TYPO3 installations to versions 6.2.16 or 7.6.1, which contain patches addressing the input validation gaps in the Extension Manager. Additionally, implementing proper output encoding for all user-provided data within the TYPO3 administration interface can serve as a secondary defense mechanism. Network-level protections such as web application firewalls can help detect and block malicious payloads attempting to exploit this vulnerability. Organizations should also conduct thorough security assessments of their TYPO3 installations to identify any custom extensions that might be vulnerable to similar input handling issues. The ATT&CK framework categorizes this vulnerability under T1566 - Phishing with Malicious Attachments, as attackers can exploit this weakness through malicious extension packages delivered via phishing campaigns or compromised extension repositories. Regular security monitoring and vulnerability scanning should be implemented to detect any attempts to exploit this weakness, while maintaining up-to-date security patches ensures comprehensive protection against both known and emerging threats targeting TYPO3 installations.