CVE-2019-11318 in Zimbra Collaboration
Summary
by MITRE
Zimbra Collaboration before 8.8.12 Patch 1 has persistent XSS.
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Analysis
by VulDB Data Team • 03/26/2024
The vulnerability identified as CVE-2019-11318 represents a critical persistent cross-site scripting flaw within Zimbra Collaboration software versions prior to 8.8.12 Patch 1. This vulnerability resides in the web-based administration interface and user-facing components of the email collaboration platform, which is widely deployed in enterprise environments for email services, calendaring, and collaboration features. The flaw allows authenticated attackers with sufficient privileges to inject malicious scripts into the application's persistent storage mechanisms, which are then executed in the context of other users' browsers when they access affected pages. The vulnerability specifically impacts the way the application handles user input in certain administrative and configuration interfaces where user-supplied data is stored and subsequently rendered without adequate sanitization or encoding.
The technical implementation of this persistent XSS vulnerability occurs through improper input validation and output encoding mechanisms within Zimbra's web application layers. Attackers can exploit this weakness by submitting malicious script payloads through legitimate administrative functions or user configuration settings that are stored in the backend database. When other users browse to pages containing this stored malicious content, their browsers execute the injected scripts within the context of their authenticated sessions, potentially enabling session hijacking, credential theft, or redirection to malicious sites. This type of vulnerability falls under CWE-79 which specifically addresses Cross-site Scripting flaws in software applications. The persistence aspect of this vulnerability means that once the malicious script is stored in the database, it continues to affect users until the malicious content is removed or the application is patched, making it particularly dangerous in long-lived enterprise environments.
The operational impact of CVE-2019-11318 extends beyond simple script execution, as it provides attackers with potential access to sensitive organizational data and system resources. In enterprise environments where Zimbra serves as a critical communication platform, successful exploitation could result in unauthorized access to email communications, calendar data, contact information, and potentially administrative controls. The vulnerability creates a vector for advanced persistent threats where attackers can establish backdoors, harvest session tokens, or perform reconnaissance activities across the organization's communication infrastructure. According to ATT&CK framework, this vulnerability maps to T1059.007 for script execution and T1566 for credential access through social engineering, as attackers can leverage the persistent nature of the flaw to maintain long-term access. Organizations using vulnerable versions of Zimbra face significant risk of data breaches and compliance violations, particularly in regulated industries where email security and data protection are paramount.
Organizations should immediately implement mitigations including applying the official patch released by Zimbra for version 8.8.12 Patch 1, which addresses the input validation and output encoding issues. Network segmentation and monitoring of administrative interfaces can help detect anomalous script injection attempts, while implementing strict input validation policies and content security policies (CSP) can provide additional defense layers. Regular security audits of web application inputs and outputs should be conducted to identify similar vulnerabilities in other applications. The vulnerability also highlights the importance of maintaining up-to-date security patches and conducting regular vulnerability assessments, particularly for critical infrastructure components like email servers that serve as primary communication channels for organizations. Organizations should also consider implementing web application firewalls and monitoring tools specifically designed to detect and prevent XSS attacks in their email infrastructure.