CVE-2016-7223 in Windows
Summary
by MITRE
Virtual Hard Disk Driver in Microsoft Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, and 1607, and Windows Server 2016 does not properly restrict access to files, which allows local users to gain privileges via a crafted application, aka "VHD Driver Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 09/30/2022
The CVE-2016-7223 vulnerability represents a critical elevation of privilege flaw within Microsoft's Virtual Hard Disk driver implementation across multiple operating system versions. This vulnerability specifically affects Windows 8.1, Windows Server 2012 R2, Windows RT 8.1, Windows 10 versions 1511 and 1607, and Windows Server 2016. The core issue stems from improper access control mechanisms within the VHD driver that fails to adequately restrict file access permissions. This flaw enables local attackers to craft malicious applications that can escalate their privileges from standard user level to system level access, fundamentally compromising the security model of affected systems.
The technical root cause of this vulnerability lies in the insufficient validation and enforcement of access controls within the Virtual Hard Disk driver component. When a malicious application attempts to interact with VHD files, the driver fails to properly validate the requesting process's privileges and access rights. This improper access restriction creates a pathway for privilege escalation where an attacker can manipulate the driver's behavior to gain unauthorized system-level access. The vulnerability operates at the kernel level, making it particularly dangerous as it bypasses standard user-mode security boundaries. This type of flaw aligns with CWE-284, which addresses improper access control issues in software systems, specifically targeting inadequate privilege management within operating system components.
The operational impact of CVE-2016-7223 is severe and far-reaching within enterprise environments where multiple users interact with affected systems. Local attackers who successfully exploit this vulnerability can execute arbitrary code with system-level privileges, potentially leading to complete system compromise. Once elevated, attackers can install malware, modify system files, access sensitive data, and establish persistent backdoors. The vulnerability is particularly concerning because it requires no network connectivity for exploitation, making it a local privilege escalation vector that can be leveraged from within the compromised system itself. This characteristic places it in the ATT&CK framework under the privilege escalation tactic, specifically targeting the use of driver manipulation for unauthorized system access. Organizations running affected Windows versions face significant risk as this vulnerability can be exploited by malicious insiders or attackers who have already gained initial access to a system.
Mitigation strategies for CVE-2016-7223 primarily involve applying the official Microsoft security updates released in the July 2016 security bulletin. System administrators should prioritize patch deployment across all affected Windows versions, particularly in enterprise environments where the risk of exploitation is highest. Additional protective measures include implementing least privilege principles, disabling unnecessary virtualization features, and monitoring for suspicious file access patterns. Security solutions should be configured to detect and alert on unusual driver behavior or privilege escalation attempts. Organizations should also consider implementing application whitelisting policies to prevent unauthorized applications from executing on affected systems. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and highlights the necessity of comprehensive vulnerability management programs that address both known and emerging threats in operating system components.