CVE-2017-4916 in Workstation Pro
Summary
by MITRE
VMware Workstation Pro/Player contains a NULL pointer dereference vulnerability that exists in the vstor2 driver. Successful exploitation of this issue may allow host users with normal user privileges to trigger a denial-of-service in a Windows host machine.
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Analysis
by VulDB Data Team • 12/25/2020
The vulnerability identified as CVE-2017-4916 represents a critical NULL pointer dereference flaw within the VMware Workstation Pro and Player virtualization software, specifically affecting the vstor2 driver component. This issue resides in the Windows host operating system environment where VMware Workstation creates virtual machine instances. The vulnerability manifests when the vstor2 driver fails to properly validate pointer references during certain operational sequences, leading to a scenario where a null pointer is dereferenced, causing the driver to crash and ultimately resulting in system instability.
The technical exploitation of this vulnerability occurs through a carefully crafted sequence of operations that triggers the NULL pointer dereference condition within the vstor2 driver. This driver is responsible for handling storage operations within the virtualized environment, particularly managing virtual storage devices and their interactions with the host system. When a normal user account on the Windows host attempts to interact with virtual storage components in a manner that causes the driver to process an uninitialized or null pointer, the system experiences a segmentation fault or access violation that terminates the driver process and potentially affects the entire host machine stability.
From an operational impact perspective, this vulnerability presents a significant denial-of-service risk that can be exploited by unprivileged users to disrupt normal system operations. The attack vector requires minimal privileges since normal user accounts can trigger the condition without requiring administrative rights. This makes the vulnerability particularly concerning for environments where multiple users share the same host system or where guest virtual machines are used in multi-user scenarios. The potential for system instability extends beyond simple service interruption, as the driver crash can cause unexpected shutdowns or require manual system restarts to restore normal operation.
Security professionals should recognize this vulnerability as aligning with CWE-476, which specifically addresses NULL pointer dereference conditions that can lead to system crashes and denial-of-service scenarios. The vulnerability also maps to ATT&CK technique T1499.001, which covers network denial of service attacks, though in this case the attack occurs at the host operating system level rather than network infrastructure. Organizations utilizing VMware Workstation Pro or Player should prioritize applying vendor patches immediately, as the vulnerability exists in multiple versions of the software and can be reliably exploited by attackers with basic user privileges. The recommended mitigation strategy involves updating to the latest VMware Workstation releases that contain fixes for this specific driver-level issue, combined with monitoring for unusual system crashes or driver-related errors that may indicate exploitation attempts.
The broader implications of this vulnerability extend to virtualization security practices, demonstrating how driver-level flaws in virtualization software can create attack surfaces that bypass traditional privilege boundaries. This type of vulnerability underscores the importance of thorough security testing for virtualization components and highlights the need for maintaining updated virtualization environments to prevent exploitation by adversaries seeking to disrupt host system operations. Organizations should implement additional monitoring for suspicious virtual storage operations and consider restricting user access to virtualization features when possible, particularly in shared or multi-tenant environments where the risk of exploitation is heightened.