CVE-2018-6969 in Tools
Summary
by MITRE
VMware Tools (10.x and prior before 10.3.0) contains an out-of-bounds read vulnerability in HGFS. Successful exploitation of this issue may lead to information disclosure or may allow attackers to escalate their privileges on the guest VMs. In order to be able to exploit this issue, file sharing must be enabled.
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Analysis
by VulDB Data Team • 04/09/2023
The vulnerability identified as CVE-2018-6969 represents a critical out-of-bounds read flaw within VMware Tools version 10.x and earlier releases before 10.3.0, specifically affecting the Host-Guest File System (HGFS) component. This issue resides in the VMware Tools implementation that facilitates communication between the guest operating system and the host system, particularly when file sharing functionality is enabled. The vulnerability manifests as an improper bounds checking mechanism within the HGFS driver, which fails to validate input parameters before processing them, creating a potential attack vector for malicious actors.
The technical exploitation of this vulnerability occurs through the HGFS protocol which enables file sharing between host and guest virtual machines. When file sharing is enabled, the vulnerable VMware Tools component processes guest requests without adequate validation of buffer boundaries, allowing attackers to craft malicious input that triggers memory access beyond allocated buffer limits. This out-of-bounds read condition can result in information disclosure, where sensitive memory contents are exposed to unauthorized parties, or potentially enable privilege escalation attacks that leverage the information leak to gain elevated privileges within the guest operating system. The vulnerability specifically impacts the VMware Tools service running within the guest VM, making it particularly concerning for environments where guest VMs are not properly isolated from malicious actors.
From an operational perspective, the impact of this vulnerability extends beyond simple information disclosure to potentially compromise entire virtualized environments. The requirement for file sharing to be enabled creates a specific attack surface that organizations must monitor and control, as it represents a fundamental security weakness in VMware virtualization deployments. Attackers could leverage this vulnerability to extract sensitive data from memory, potentially including credentials, encryption keys, or other confidential information stored within the guest VM's memory space. The privilege escalation aspect of this vulnerability means that even if initial access is limited, attackers could potentially gain root or administrative privileges within the guest operating system, effectively compromising the entire virtual machine.
Organizations should implement immediate mitigations including upgrading VMware Tools to version 10.3.0 or later, which contains the necessary patches to address the out-of-bounds read vulnerability. Additionally, administrators should disable file sharing functionality in virtual machines where it is not strictly required, as this significantly reduces the attack surface for exploitation. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions in software implementations, and represents a typical example of how virtualization platforms can introduce security risks through improper input validation. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and credential access patterns, as attackers could use the information disclosure to obtain credentials or escalate privileges within compromised VMs. Security monitoring should focus on detecting anomalous file sharing activities and memory access patterns that could indicate exploitation attempts, while also ensuring proper patch management protocols are in place to prevent similar vulnerabilities from remaining unaddressed in future deployments.