CVE-2019-5527 in ESXi
Summary
by MITRE
ESXi, Workstation, Fusion, VMRC and Horizon Client contain a use-after-free vulnerability in the virtual sound device. VMware has evaluated the severity of this issue to be in the Important severity range with a maximum CVSSv3 base score of 8.5.
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Analysis
by VulDB Data Team • 10/01/2020
The vulnerability identified as CVE-2019-5527 represents a critical use-after-free flaw within VMware's virtual sound device implementation across multiple products including ESXi, Workstation, Fusion, VMRC, and Horizon Client. This issue manifests in the virtual sound device component that handles audio processing for virtual machines, creating a potential attack vector where malicious actors could exploit improper memory management practices. The vulnerability occurs when the virtual sound device fails to properly validate memory references after objects have been freed, allowing for potential code execution or system compromise. The CVSSv3 base score of 8.5 indicates a high-severity threat that could enable remote code execution in affected environments. This type of vulnerability falls under CWE-416, which specifically addresses use-after-free conditions where software continues to reference memory after it has been freed, creating opportunities for attackers to manipulate memory contents or execute arbitrary code.
The technical exploitation of this vulnerability requires a sophisticated attacker who can manipulate the virtual sound device within a virtual machine environment to trigger the use-after-free condition. The attack typically involves crafting specific audio data or commands that cause the virtual sound device to reference freed memory locations, potentially leading to memory corruption and unauthorized code execution. Attackers could leverage this flaw to gain elevated privileges within the virtualized environment or potentially escape the confines of the virtual machine to target the underlying host system. The impact extends beyond individual virtual machines as compromised virtual sound devices could enable attackers to establish persistent access points within the virtual infrastructure, particularly concerning the shared resources and memory management systems of the host platform. This vulnerability directly impacts VMware's virtualization security model and could undermine the isolation guarantees that virtual machines are designed to maintain.
The operational consequences of CVE-2019-5527 are severe for organizations relying on VMware virtualization solutions, as it represents a potential pathway for attackers to compromise entire virtualized environments. Organizations utilizing ESXi, Workstation, Fusion, VMRC, and Horizon Client products face significant risks including unauthorized access to sensitive data, potential privilege escalation, and system compromise. The vulnerability affects both the guest operating systems running within virtual machines and the host systems managing these virtual environments, creating a multi-layered security threat. Enterprises with extensive virtualization deployments could face widespread impact if attackers successfully exploit this flaw, potentially leading to data breaches, service disruptions, and compliance violations. The vulnerability's presence across multiple VMware products means that organizations cannot simply patch one component to resolve the issue, requiring comprehensive remediation across their entire virtualization infrastructure.
Mitigation strategies for CVE-2019-5527 should prioritize immediate patch deployment from VMware as the primary defense mechanism, with additional security controls implemented to reduce attack surface. Organizations should disable unnecessary virtual sound device functionality where possible and implement network segmentation to limit potential exploitation paths. Security teams should monitor virtual machine activity for unusual audio processing patterns or memory access anomalies that could indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under privilege escalation and remote code execution techniques, emphasizing the need for layered defensive measures including endpoint detection and response solutions. Regular vulnerability assessments and penetration testing should be conducted to identify potential exploitation vectors, while access controls should be strictly enforced to limit who can interact with virtual sound device configurations. Organizations should also consider implementing virtualization-specific security monitoring tools that can detect anomalous behavior patterns associated with memory corruption exploits. The remediation process must be comprehensive, covering all affected VMware products and ensuring that patches are applied consistently across the entire virtual infrastructure to prevent exploitation attempts.