CVE-2016-7138 in Plone
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the URL checking infrastructure in Plone CMS 5.x through 5.0.6, 4.x through 4.3.11, and 3.3.x through 3.3.6 allows remote attackers to inject arbitrary web script or HTML via a crafted URL.
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Analysis
by VulDB Data Team • 09/26/2022
The CVE-2016-7138 vulnerability represents a critical cross-site scripting flaw within the Plone Content Management System's URL checking infrastructure. This vulnerability affects multiple versions of Plone CMS including the 5.x series through 5.0.6, 4.x series through 4.3.11, and 3.3.x series through 3.3.6, demonstrating the widespread impact of this particular security weakness. The vulnerability stems from insufficient input validation and sanitization mechanisms within the URL processing components of the CMS, creating a pathway for malicious actors to execute arbitrary web scripts or HTML code within the context of affected user sessions.
The technical exploitation of this vulnerability occurs when the Plone CMS processes crafted URLs through its URL checking infrastructure without proper sanitization of user-supplied input. When a malicious URL containing script code is submitted to the system, the vulnerable infrastructure fails to properly escape or filter the input before it is rendered in the web interface. This allows attackers to inject malicious scripts that execute in the browser context of legitimate users who view pages containing the crafted URLs. The vulnerability specifically targets the URL validation and processing mechanisms, which are fundamental components used for link management, external resource handling, and web integration within the CMS framework.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the ability to perform various malicious activities including session hijacking, credential theft, data exfiltration, and redirection to malicious sites. An attacker could craft URLs that, when clicked by authenticated users, would execute scripts that steal session cookies, capture user input, or redirect users to phishing sites. The vulnerability is particularly dangerous in environments where administrators or content creators frequently interact with external links, as these users represent high-value targets for attack. The cross-site scripting nature means that the attack can persist across different user sessions and potentially affect multiple users within the same organization, making this a significant threat to organizational security.
Mitigation strategies for CVE-2016-7138 should focus on immediate patching of affected Plone CMS versions to the latest secure releases, as this represents the most effective defense against the vulnerability. Organizations should also implement proper input validation and output encoding mechanisms within their web applications, ensuring that all user-supplied data is properly sanitized before processing. The implementation of Content Security Policy headers can provide additional protection against script execution, while regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other components of the web infrastructure. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and represents a classic example of how inadequate input validation can lead to severe security consequences. Organizations should also consider implementing web application firewalls and monitoring systems to detect and prevent exploitation attempts, while following ATT&CK framework techniques for defensive measures against web-based attacks.