CVE-2021-41343 in Windows
Summary
by MITRE • 10/13/2021
Windows Fast FAT File System Driver Information Disclosure Vulnerability This CVE ID is unique from CVE-2021-38662.
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Analysis
by VulDB Data Team • 10/15/2021
The Windows Fast FAT File System Driver Information Disclosure Vulnerability represents a critical security flaw within the Windows operating system's file handling infrastructure. This vulnerability specifically affects the FAT file system driver implementation and was identified as distinct from the related CVE-2021-38662, indicating separate attack surfaces and exploitation mechanisms. The flaw resides in how the system processes and handles file system operations within the FAT file system context, creating potential pathways for unauthorized information disclosure.
The technical root cause of this vulnerability stems from improper handling of file system metadata and directory entries within the Fast FAT driver implementation. When processing certain file operations or directory traversals, the driver fails to properly validate or sanitize input parameters, leading to information leakage through memory corruption or improper access control mechanisms. This type of vulnerability aligns with CWE-200, which categorizes information exposure flaws, and represents a classic example of insufficient output filtering or improper resource management in kernel-level drivers. The vulnerability manifests when the system processes file system operations that involve FAT file system structures, particularly during directory enumeration or file attribute access scenarios.
The operational impact of this information disclosure vulnerability extends beyond simple data leakage, potentially enabling attackers to gain insights into system file structures, directory layouts, and potentially sensitive file metadata. An attacker could leverage this vulnerability to perform reconnaissance activities, mapping out file system hierarchies and identifying potentially sensitive files or directories that might not otherwise be visible through normal system operations. The implications are particularly concerning in enterprise environments where FAT file systems might be used for removable media or legacy compatibility purposes, as this information could facilitate further attacks or provide attackers with additional targeting capabilities. This vulnerability falls under the ATT&CK technique T1083 for discovering file and directory permissions, and T1069 for permission groups discovery, as it enables unauthorized access to file system information that would normally be restricted.
Mitigation strategies for this vulnerability should encompass both immediate patch deployment and operational security measures. Microsoft has released security updates addressing this specific flaw, and system administrators should prioritize applying these patches across all affected Windows systems, particularly those that utilize FAT file systems. Network segmentation and access controls should be reinforced to limit exposure of systems running FAT file systems to untrusted networks or users. Additionally, monitoring solutions should be enhanced to detect anomalous file system access patterns or directory traversal activities that might indicate exploitation attempts. Regular security assessments and vulnerability scanning should include specific checks for FAT file system driver configurations, ensuring that systems are not inadvertently exposing sensitive information through improper file system handling. The vulnerability demonstrates the importance of kernel-level security hardening and proper input validation in system drivers, as these components represent critical attack surfaces that can provide significant operational advantages to threat actors.