CVE-2016-7463 in ESXi
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Host Client in VMware vSphere Hypervisor (aka ESXi) 5.5 and 6.0 allows remote authenticated users to inject arbitrary web script or HTML via a crafted VM.
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Analysis
by VulDB Data Team • 09/19/2024
The CVE-2016-7463 vulnerability represents a critical cross-site scripting flaw within VMware vSphere Hypervisor's Host Client interface affecting versions 5.5 and 6.0. This vulnerability resides in the web-based management interface that administrators use to interact with the hypervisor environment, creating a significant attack surface that could be exploited by malicious actors. The flaw specifically manifests when the system processes user-supplied input from virtual machine configurations, allowing attackers to inject malicious scripts that execute within the context of other users' sessions. This type of vulnerability directly violates the principle of input validation and sanitization that forms the foundation of web application security. The vulnerability is categorized under CWE-79 as Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security that enables attackers to inject malicious code into web pages viewed by other users.
The technical exploitation of this vulnerability requires an attacker to have valid authentication credentials to access the vSphere Host Client interface, making it an authenticated XSS vulnerability rather than a purely remote threat. Attackers can craft malicious virtual machine configurations that contain script payloads which are then rendered in the web interface without proper sanitization. When other authenticated users view these malicious VM entries, their browsers execute the injected scripts within their session context, potentially leading to session hijacking, data exfiltration, or privilege escalation. The attack vector specifically targets the web-based management interface where virtual machine configurations are displayed, making it particularly dangerous in enterprise environments where multiple administrators interact with the same management console. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as it enables attackers to execute JavaScript code in victim browsers through the manipulated web interface.
The operational impact of this vulnerability extends beyond simple script execution, as it can be leveraged for more sophisticated attacks within the virtualized environment. An attacker who successfully exploits this vulnerability could potentially access sensitive management functions, view other users' sessions, or manipulate virtual machine configurations to establish persistent access points. The vulnerability's presence in both vSphere 5.5 and 6.0 versions indicates it was a widespread issue affecting multiple generations of VMware's hypervisor platform, creating substantial risk for organizations maintaining legacy systems. Organizations with large vSphere deployments face significant exposure as a single compromised authenticated user account could potentially compromise the entire management interface. The vulnerability also creates potential for privilege escalation attacks where attackers could manipulate the interface to access higher-privilege functions, particularly if the compromised user has administrative rights within the vSphere environment. This type of vulnerability is particularly concerning in cloud and data center environments where centralized management of multiple hypervisors is common.
Mitigation strategies for CVE-2016-7463 should focus on immediate patching of affected vSphere versions, with VMware releasing security updates specifically addressing this vulnerability in their subsequent releases. Organizations should implement network segmentation and access controls to limit the number of users with administrative privileges to the vSphere Host Client, reducing the potential attack surface. Regular security audits of virtualization management interfaces should include checks for input validation weaknesses and proper sanitization of user-supplied data. Security monitoring should be enhanced to detect unusual activities in the vSphere management interface, particularly around virtual machine creation and configuration changes. The implementation of web application firewalls and input validation controls at the network perimeter can provide additional layers of protection against exploitation attempts. Organizations should also consider implementing multi-factor authentication for vSphere management interfaces and regularly review user access rights to ensure least privilege principles are maintained. The vulnerability serves as a reminder of the critical importance of input validation in web applications and demonstrates how even authenticated vulnerabilities can create substantial security risks in enterprise virtualization environments.