CVE-2017-4905 in ESXi
Summary
by MITRE
VMware ESXi 6.5 without patch ESXi650-201703410-SG, 6.0 U3 without patch ESXi600-201703401-SG, 6.0 U2 without patch ESXi600-201703403-SG, 6.0 U1 without patch ESXi600-201703402-SG, 5.5 without patch ESXi550-201703401-SG; Workstation Pro / Player 12.x prior to 12.5.5; and Fusion Pro / Fusion 8.x prior to 8.5.6 have uninitialized memory usage. This issue may lead to an information leak.
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Analysis
by VulDB Data Team • 12/26/2020
The vulnerability identified as CVE-2017-4905 represents a critical uninitialized memory usage flaw affecting multiple versions of VMware ESXi hypervisor and desktop virtualization products. This issue specifically impacts VMware ESXi versions 5.5, 6.0 U1 through U3, and 6.5 without their respective security patches, as well as VMware Workstation Pro/Player 12.x prior to 12.5.5 and Fusion Pro/8.x prior to 8.5.6. The vulnerability stems from improper memory management practices where the system fails to properly initialize memory regions before use, creating potential pathways for information disclosure.
The technical flaw manifests when the virtualization platform allocates memory blocks without ensuring they are properly cleared or initialized before being utilized by virtual machines or system processes. This uninitialized memory may contain residual data from previous operations, including sensitive information such as cryptographic keys, passwords, or other confidential data that was previously stored in those memory locations. According to CWE-1282, this vulnerability falls under uninitialized memory access, which is a well-documented category of memory safety issues that can lead to information exposure. The flaw is particularly concerning because it operates at the hypervisor level where multiple virtual machines share underlying physical resources, potentially allowing an attacker to exploit this weakness to extract confidential information from other virtual environments.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential attack vectors for more sophisticated exploitation techniques. An attacker who can successfully leverage this uninitialized memory usage could potentially access sensitive data from other virtual machines running on the same physical host, compromising the fundamental security isolation that virtualization platforms are designed to provide. This issue aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to credential access and defense evasion, where attackers might use information leaks to gain additional footholds or to avoid detection by clearing forensic traces. The vulnerability affects the core integrity of the virtualization environment, potentially undermining the security posture of organizations relying on VMware infrastructure for their computing needs.
Mitigation strategies for CVE-2017-4905 primarily focus on immediate patch deployment and system hardening measures. Organizations should prioritize applying the vendor-supplied patches ESXi650-201703410-SG for ESXi 6.5, ESXi600-201703401-SG for ESXi 6.0 U3, ESXi600-201703403-SG for ESXi 6.0 U2, ESXi600-201703402-SG for ESXi 6.0 U1, and ESXi550-201703401-SG for ESXi 5.5. Additionally, VMware recommends upgrading Workstation Pro/Player to version 12.5.5 and Fusion Pro/8.x to version 8.5.6 to address the desktop virtualization components. System administrators should also implement memory monitoring tools to detect unusual memory access patterns and consider implementing additional network segmentation measures to limit the potential impact of any successful exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date security patches in virtualized environments where the compromise of one component can potentially affect multiple virtual machines and their associated data.