CVE-2016-2078 in vCenter Server
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Web Client in VMware vCenter Server 5.1 before update 3d, 5.5 before update 3d, and 6.0 before update 2 on Windows allows remote attackers to inject arbitrary web script or HTML via the flashvars parameter.
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Analysis
by VulDB Data Team • 12/14/2018
The vulnerability identified as CVE-2016-2078 represents a critical cross-site scripting flaw within VMware vCenter Server's Web Client component. This security weakness affects multiple versions of the vCenter Server platform including versions 5.1 prior to update 3d, 5.5 prior to update 3d, and 6.0 prior to update 2 on Windows operating systems. The vulnerability specifically resides in how the Web Client processes the flashvars parameter, creating an avenue for malicious actors to execute arbitrary web scripts or HTML code within the context of authenticated user sessions.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the Web Client's parameter handling mechanism. When the flashvars parameter is processed without proper encoding or filtering, it allows attackers to inject malicious scripts that can be executed in the browser of authenticated users. This flaw operates at the application layer and leverages the trust relationship between the user's browser and the vCenter Server interface, making it particularly dangerous in enterprise environments where administrative privileges are commonly held by users.
The operational impact of CVE-2016-2078 extends beyond simple script injection, as it can enable attackers to perform a wide range of malicious activities including session hijacking, data exfiltration, and privilege escalation. Attackers can craft malicious payloads that appear legitimate to users, potentially leading to unauthorized access to sensitive virtual machine configurations, network settings, and administrative controls. The vulnerability is particularly concerning in data center environments where vCenter Server serves as the central management interface for virtualized infrastructure, making it a prime target for attackers seeking to compromise entire virtual environments.
This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and maps to ATT&CK technique T1059.007 for script injection and T1566 for credential access through social engineering. The attack surface is significantly expanded when considering that vCenter Server administrators typically possess elevated privileges within virtualized environments, making successful exploitation potentially devastating for enterprise security postures. Organizations utilizing affected versions of VMware vCenter Server face increased risk of unauthorized access to critical virtual infrastructure management capabilities, potentially leading to complete compromise of virtualized environments and associated data.
The recommended mitigation strategy involves immediate deployment of the vendor-provided security patches for each affected version, specifically updates 3d for vCenter Server 5.1 and 5.5, and update 2 for vCenter Server 6.0. Additionally, organizations should implement network segmentation to limit access to vCenter Server interfaces, enforce strict access controls, and monitor for suspicious activity patterns that may indicate exploitation attempts. Regular vulnerability assessments and security awareness training for administrators can further reduce the risk of successful exploitation, while maintaining up-to-date security monitoring solutions helps detect potential malicious activity in real-time.