CVE-2017-8802 in Zimbra Collaboration
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Zimbra Collaboration Suite (aka ZCS) before 8.8.0 Beta2 might allow remote attackers to inject arbitrary web script or HTML via vectors related to the "Show Snippet" functionality.
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Analysis
by VulDB Data Team • 02/03/2020
The Cross-site scripting vulnerability identified as CVE-2017-8802 affects the Zimbra Collaboration Suite version prior to 8.8.0 Beta2, representing a significant security weakness in email and collaboration platforms that can compromise user data and system integrity. This vulnerability specifically targets the "Show Snippet" functionality within the Zimbra interface, which is designed to display preview content from emails or messages. The flaw enables remote attackers to inject malicious web scripts or HTML code into the application's response, potentially affecting all users interacting with the vulnerable system. Such vulnerabilities are particularly dangerous in enterprise environments where Zimbra serves as a critical communication platform for organizations handling sensitive business and personal information.
The technical nature of this vulnerability stems from inadequate input validation and output encoding within the Zimbra application's snippet rendering mechanism. When the system processes email content for display in the snippet feature, it fails to properly sanitize user-supplied data, creating an opening for malicious actors to embed XSS payloads. This represents a classic example of CWE-79 - Improper Neutralization of Input During Web Page Generation, where the application fails to properly encode or escape user-controllable data before including it in dynamically generated web content. The vulnerability manifests when attackers craft specially formatted email messages or content that, when processed by the snippet functionality, executes unintended JavaScript code in the victim's browser context. Attackers can exploit this weakness to perform session hijacking, steal cookies, redirect users to malicious sites, or execute arbitrary commands within the user's browser session.
The operational impact of CVE-2017-8802 extends beyond simple data theft, potentially enabling attackers to gain unauthorized access to sensitive email communications and user credentials within the Zimbra environment. This vulnerability can be leveraged in targeted phishing campaigns where attackers craft emails with embedded malicious snippets that execute when users preview messages in their inbox. The attack surface includes all Zimbra users who interact with email content that triggers the snippet functionality, making it particularly dangerous in large enterprise deployments where thousands of users may be exposed. From an ATT&CK framework perspective, this vulnerability aligns with T1059 - Command and Scripting Interpreter and T1566 - Phishing, as it enables both code execution within user browsers and social engineering attacks that leverage the platform's legitimate functionality. The vulnerability also relates to T1531 - Account Access Removal, as successful exploitation could lead to unauthorized access to user accounts and their associated data.
Organizations utilizing Zimbra Collaboration Suite prior to version 8.8.0 Beta2 should prioritize immediate patching and implementation of compensating controls to address this vulnerability. The recommended mitigation strategy involves upgrading to Zimbra Collaboration Suite 8.8.0 Beta2 or later versions where the XSS vulnerability has been addressed through proper input sanitization and output encoding mechanisms. Security teams should also implement additional protective measures including web application firewalls, content security policies, and regular security assessments to monitor for similar vulnerabilities. Network administrators should consider implementing email filtering rules that detect and block suspicious content patterns, while security monitoring systems should be configured to detect potential exploitation attempts through anomalous user behavior or unusual network activity related to the vulnerable snippet functionality. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against persistent threats targeting enterprise collaboration platforms.