CVE-2019-8945 in Zimbra Collaboration
Summary
by MITRE
Zimbra Collaboration 8.7.x - 8.8.11P2 contains persistent XSS.
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Analysis
by VulDB Data Team • 03/27/2024
The vulnerability identified as CVE-2019-8945 represents a persistent cross-site scripting flaw within Zimbra Collaboration software versions ranging from 8.7.x through 8.8.11P2. This security defect allows attackers to inject malicious scripts into web applications that persist in the system and execute when other users view the affected content. The vulnerability specifically affects the web interface components of the email collaboration platform, which serves as a critical communication infrastructure for enterprise organizations. Persistent XSS vulnerabilities are particularly dangerous because they can remain undetected for extended periods while continuously compromising user sessions and potentially enabling broader attack vectors. The flaw stems from inadequate input validation and output encoding mechanisms within the application's web framework, creating opportunities for malicious actors to manipulate user data and system behavior through crafted script payloads.
The technical implementation of this vulnerability occurs when user-supplied input containing malicious script code is improperly sanitized before being stored and subsequently rendered in web pages. Attackers can exploit this weakness by submitting specially crafted content through various application interfaces including email composition forms, calendar entries, or contact management features. When other users access these stored malicious entries, the injected scripts execute in their browser context, potentially stealing session cookies, redirecting users to malicious sites, or performing unauthorized actions on their behalf. The vulnerability operates at the application layer and leverages the trust relationship between the web application and its users, making it particularly effective for privilege escalation and data exfiltration attacks. This type of flaw aligns with CWE-79 which categorizes cross-site scripting vulnerabilities as weaknesses in input validation and output encoding, specifically targeting the failure to properly sanitize user-controllable data.
The operational impact of CVE-2019-8945 extends beyond simple script execution, potentially enabling sophisticated attack scenarios that can compromise entire email infrastructures. Organizations utilizing affected Zimbra versions face risks of credential theft, unauthorized access to sensitive email communications, and potential lateral movement within network environments through session hijacking. The persistent nature of the vulnerability means that once exploited, malicious content remains active until manually removed, providing attackers with sustained access to compromised systems. Enterprise users may experience unauthorized modification of calendar events, contact information, or email content, leading to operational disruptions and potential compliance violations. The vulnerability also creates opportunities for attackers to establish backdoors or deploy additional malware through the executed scripts, making it a significant threat to organizational security posture and data integrity.
Organizations should implement immediate mitigation strategies including applying the vendor-provided security patches released for this vulnerability, which typically address the input validation and output encoding deficiencies. Network segmentation and monitoring solutions should be enhanced to detect unusual script injection patterns in web traffic, while security teams should conduct thorough vulnerability assessments of all Zimbra installations to identify potential exploitation attempts. User education regarding suspicious email content and calendar entries remains crucial, as social engineering components often accompany XSS attacks. The implementation of web application firewalls and content security policies can provide additional protection layers, while regular security audits should verify proper input sanitization across all application interfaces. Organizations should also consider implementing strict access controls and monitoring for administrative functions to limit the potential damage from successful exploitation attempts. This vulnerability demonstrates the importance of maintaining current security patches and implementing defense-in-depth strategies to protect against persistent threats in enterprise email systems.