CVE-2016-6846 in Open-Xchange
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Open-Xchange (OX) AppSuite backend before 7.6.2-rev59, 7.8.0 before 7.8.0-rev38, 7.8.2 before 7.8.2-rev8; AppSuite frontend before 7.6.2-rev47, 7.8.0 before 7.8.0-rev30, and 7.8.2 before 7.8.2-rev8; Office Web before 7.6.2-rev16, 7.8.0 before 7.8.0-rev10, and 7.8.2 before 7.8.2-rev5; and Documentconverter-API before 7.8.2-rev5 allows remote attackers to inject arbitrary web script or HTML.
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Analysis
by VulDB Data Team • 08/23/2020
The CVE-2016-6846 vulnerability represents a critical cross-site scripting flaw that affected multiple components within the Open-Xchange AppSuite ecosystem. This vulnerability existed across various versions of the backend, frontend, Office Web interface, and Documentconverter-API components, creating a widespread attack surface for malicious actors. The vulnerability stems from insufficient input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before rendering it within web pages. Attackers could exploit this weakness by crafting malicious payloads that would be executed in the context of other users' browsers, potentially leading to session hijacking, data theft, or further compromise of the affected systems. The vulnerability specifically impacts versions prior to the mentioned revision numbers, indicating that proper security patches were implemented to address the issue. This XSS vulnerability aligns with CWE-79, which classifies cross-site scripting as a critical weakness in web applications where untrusted data is improperly handled during web page generation. The attack vector leverages the trust relationship between the web application and its users, making it particularly dangerous in enterprise environments where sensitive business data is processed through the Open-Xchange platform.
The technical exploitation of this vulnerability involves injecting malicious scripts into input fields or parameters that are subsequently displayed without proper sanitization. When legitimate users interact with the vulnerable application, their browsers execute the injected code within the context of their authenticated sessions. This behavior creates a persistent threat where attackers can manipulate the application's functionality, steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. The vulnerability affects both server-side and client-side components, making it particularly challenging to mitigate completely. The issue manifests across multiple product lines including the core AppSuite backend, the user-facing frontend interfaces, the Office Web component for document editing, and the Documentconverter-API for file conversion services. Each of these components likely processes user input through similar pathways that fail to implement adequate security controls, creating consistent attack points throughout the application stack. The vulnerability's persistence across multiple versions and components suggests a fundamental flaw in the input handling architecture rather than isolated implementation errors, which would require comprehensive architectural review and remediation.
The operational impact of this vulnerability extends beyond simple script execution, potentially enabling sophisticated attack scenarios that could compromise entire enterprise environments. Remote attackers could leverage this vulnerability to establish persistent access through session hijacking, leading to unauthorized data access, modification, or deletion. The affected systems typically process sensitive business information, making the potential for data breaches particularly severe. Organizations relying on Open-Xchange for email, calendar, and document management services would face significant risk if this vulnerability remained unpatched, as attackers could access confidential communications, personal data, and business documents. The vulnerability also enables phishing attacks where malicious scripts could redirect users to fraudulent sites or harvest credentials from authenticated sessions. Additionally, the widespread nature of the affected components means that exploitation could potentially affect multiple services simultaneously, amplifying the overall impact. Security teams would face challenges in identifying and mitigating this vulnerability across their entire Open-Xchange deployment, requiring coordinated patching efforts across multiple system components. The vulnerability's presence in both frontend and backend components suggests that attackers could potentially escalate privileges or move laterally within the network if proper security controls were not in place.
Organizations should implement immediate remediation strategies focusing on updating all affected components to their patched versions, which address the root cause of the XSS vulnerability through proper input validation and output encoding mechanisms. The recommended mitigation approach includes deploying the latest security patches for all affected versions of the Open-Xchange AppSuite components, specifically targeting the revision numbers mentioned in the CVE description. Network segmentation and web application firewalls should be configured to monitor and filter suspicious input patterns that could indicate attempted exploitation. Regular security assessments should verify that all components have been properly updated and that no legacy versions remain operational. Input validation controls should be strengthened to ensure that all user-supplied data is properly sanitized before processing, implementing the principle of least privilege for data handling. Security monitoring should be enhanced to detect anomalous behavior patterns that could indicate exploitation attempts, particularly focusing on unusual script injection attempts or unauthorized access patterns. The vulnerability's classification under ATT&CK framework would likely map to T1059 for command and scripting interpreter, and T1566 for credential access, highlighting the need for comprehensive defensive measures. Regular security awareness training for administrators should emphasize the importance of timely patch management and the potential consequences of delayed vulnerability remediation. Organizations should also consider implementing automated patch management solutions to ensure consistent and timely deployment of security updates across their entire Open-Xchange infrastructure.