CVE-2012-4073 in Unified Computing System
Summary
by MITRE
The KVM subsystem in the client in Cisco Unified Computing System (UCS) does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers, and read or modify KVM data, via a crafted certificate, aka Bug ID CSCte90332.
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Analysis
by VulDB Data Team • 01/07/2022
The vulnerability identified as CVE-2012-4073 resides within the Kernel-based Virtual Machine subsystem of Cisco Unified Computing System clients, representing a critical security flaw in the system's certificate validation mechanisms. This weakness specifically affects the SSL/TLS certificate verification process, creating an avenue for sophisticated attackers to execute man-in-the-middle attacks against KVM (Keyboard, Video, Mouse) sessions. The vulnerability stems from the absence of proper X.509 certificate validation, which is fundamental to establishing secure communication channels in networked environments. When the KVM subsystem fails to verify server certificates, it essentially removes a crucial security layer that should ensure the authenticity and integrity of communication endpoints.
The technical exploitation of this vulnerability involves attackers crafting malicious SSL certificates that can successfully bypass the client-side verification process. This allows adversaries to establish fraudulent communication channels with the KVM client, effectively positioning themselves between the legitimate server and the client. The implications extend beyond simple eavesdropping, as attackers can actively modify data in transit, potentially altering KVM session parameters, commands, or even injecting malicious instructions. The vulnerability directly relates to CWE-295, which addresses improper certificate validation, and represents a failure in implementing proper SSL/TLS security protocols. This weakness enables attackers to impersonate legitimate KVM servers and gain unauthorized access to sensitive system management functions, potentially leading to complete system compromise.
The operational impact of CVE-2012-4073 is severe and multifaceted, particularly within enterprise data center environments where Cisco UCS systems are commonly deployed. KVM functionality provides critical remote management capabilities, allowing administrators to control servers and systems from remote locations. When this communication channel becomes vulnerable to man-in-the-middle attacks, it creates a significant risk for system integrity and data confidentiality. Attackers can intercept and modify sensitive management commands, potentially gaining unauthorized access to server configurations, system settings, or even executing arbitrary code on managed systems. The vulnerability affects the availability and integrity of system management operations, as attackers can disrupt legitimate management sessions or inject malicious payloads that persist across system operations. This risk is particularly concerning in environments where system administrators rely heavily on remote KVM access for maintenance and troubleshooting activities.
Mitigation strategies for this vulnerability require immediate implementation of several security measures to address the certificate validation weakness. Organizations should implement proper SSL certificate management practices, including the deployment of certificate pinning mechanisms where possible, and ensure that all KVM clients are configured to validate certificates against trusted certificate authorities. Network segmentation and monitoring solutions should be deployed to detect anomalous KVM traffic patterns that might indicate man-in-the-middle activity. The implementation of network access controls and firewall rules can help limit exposure to potential attackers by restricting access to KVM management interfaces. Additionally, regular security audits and vulnerability assessments should be conducted to identify and remediate similar certificate validation weaknesses in other system components. This vulnerability aligns with ATT&CK technique T1071.004, which covers application layer protocol: DNS, and represents a failure in secure communication protocols that enables credential theft and system compromise. Cisco has issued patches and updates to address this vulnerability, and organizations should ensure all UCS systems are updated to versions that properly implement certificate validation mechanisms to prevent exploitation.