CVE-2018-6982 in ESXi
Summary
by MITRE
VMware ESXi 6.7 without ESXi670-201811401-BG and VMware ESXi 6.5 without ESXi650-201811301-BG contain uninitialized stack memory usage in the vmxnet3 virtual network adapter which may lead to an information leak from host to guest.
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Analysis
by VulDB Data Team • 06/13/2023
The vulnerability identified as CVE-2018-6982 affects VMware ESXi hypervisor versions 6.5 and 6.7, specifically when certain security patches are not applied. This issue resides within the vmxnet3 virtual network adapter implementation, which is a critical component responsible for network communication between virtual machines and the physical network infrastructure. The flaw manifests as uninitialized stack memory usage, representing a fundamental programming error that can have severe implications for system security and data integrity.
The technical root cause of this vulnerability lies in the improper initialization of memory variables within the vmxnet3 driver code. When processing network packets, the driver fails to properly initialize stack memory before use, potentially leaving sensitive data from previous operations in memory locations that are subsequently exposed to guest operating systems. This memory leakage occurs during the network packet processing cycle where the virtual adapter handles incoming and outgoing network traffic between the host system and virtual machines. The uninitialized memory segments may contain remnants of previously processed data, configuration information, or other sensitive host-level data that should remain isolated from guest environments.
From an operational perspective, this vulnerability creates a significant information disclosure risk that can be exploited by malicious actors within a compromised guest operating system. The information leak could potentially expose sensitive host-level data, including system configuration details, memory contents, or other confidential information that should remain protected within the hypervisor environment. This breach of isolation represents a serious compromise to the fundamental security model of virtualization, where guest operating systems should be completely isolated from host resources and other virtual machines. The impact extends beyond simple data exposure, as leaked information could potentially be used to facilitate further attacks, including privilege escalation or targeted exploitation of other system components.
The vulnerability aligns with CWE-457, which describes "Use of Uninitialized Variable," a well-known weakness that can lead to unpredictable behavior and information disclosure. From an ATT&CK framework perspective, this issue maps to techniques involving credential access and information gathering, as attackers could leverage the information leak to gain insights into the host system configuration and potentially identify additional attack vectors. The exploitation of this vulnerability typically requires a guest operating system compromise, as the information leak occurs during normal network operations between guest and host, making it a particularly insidious threat that can be leveraged by attackers who have already gained access to a virtual machine.
Organizations should immediately apply the relevant security patches ESXi670-201811401-BG for ESXi 6.7 and ESXi650-201811301-BG for ESXi 6.5 to remediate this vulnerability. Additionally, implementing network segmentation and monitoring for unusual network activity patterns can help detect potential exploitation attempts. System administrators should also conduct thorough security assessments of their virtualized environments to ensure proper patch management and monitor for any signs of information disclosure that could indicate exploitation of this vulnerability.