CVE-2018-0877 in Windows
Summary
by MITRE
The Desktop Bridge Virtual File System (VFS) in Windows 10 1607, 1703, and 1709, Windows Server 2016 and Windows Server, version 1709 allows an elevation of privilege vulnerability due to how file paths are managed, aka "Windows Desktop Bridge VFS Elevation of Privilege Vulnerability".
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Analysis
by VulDB Data Team • 11/17/2025
The Windows Desktop Bridge Virtual File System vulnerability represents a critical elevation of privilege flaw affecting multiple Windows 10 and Server versions. This vulnerability stems from improper handling of file paths within the virtual file system component that enables desktop applications to access Windows Store applications and their resources. The vulnerability specifically impacts Windows 10 versions 1607, 1703, and 1709 along with Windows Server 2016 and Server version 1709, creating a persistent security gap that could be exploited by malicious actors to gain unauthorized system access. The issue manifests through the Desktop Bridge VFS implementation where file path resolution mechanisms fail to properly validate or sanitize access requests, allowing attackers to bypass normal security boundaries.
The technical flaw resides in the path management implementation within the Desktop Bridge Virtual File System component, which operates under the Common Weakness Enumeration framework as CWE-22 - Improper Limitation of a Pathname to a Restricted Directory. The vulnerability occurs when applications attempt to access files through the virtual file system interface, where the system fails to properly verify the legitimacy of requested file paths. This improper validation allows attackers to craft malicious path sequences that can traverse the virtual file system boundaries and access restricted resources. The flaw essentially creates a path traversal condition within the Windows application virtualization layer, enabling unauthorized access to system resources that should remain protected.
Operationally, this vulnerability enables attackers to escalate their privileges from standard user level to system level by exploiting the flawed path resolution mechanism. An attacker could leverage this vulnerability to access sensitive system files, modify protected application components, or execute arbitrary code with elevated privileges. The impact extends beyond simple privilege escalation as it can potentially allow complete system compromise, particularly when combined with other attack vectors. The vulnerability affects the core Windows security model by undermining the isolation mechanisms that separate different application contexts and user permissions, creating a fundamental weakness in the operating system's access control architecture.
Mitigation strategies should focus on immediate patch deployment for all affected Windows versions, as Microsoft released security updates addressing this specific vulnerability. Organizations should implement additional monitoring for suspicious file access patterns and path traversal attempts within the Desktop Bridge environment. The mitigation approach aligns with ATT&CK framework technique T1068 - Exploitation for Privilege Escalation, requiring comprehensive system hardening measures. Security administrators should also consider disabling unnecessary Desktop Bridge functionality where possible and implementing strict application whitelisting policies to prevent exploitation. Regular security assessments of virtual file system access controls and proper path validation mechanisms should be conducted to ensure ongoing protection against similar vulnerabilities.