CVE-2016-3340 in Windows
Summary
by MITRE
The Common Log File System (CLFS) driver in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, and 1607, and Windows Server 2016 allows local users to gain privileges via a crafted application, aka "Windows Common Log File System Driver Elevation of Privilege Vulnerability," a different vulnerability than CVE-2016-0026, CVE-2016-3332, CVE-2016-3333, CVE-2016-3334, CVE-2016-3335, CVE-2016-3338, CVE-2016-3342, CVE-2016-3343, and CVE-2016-7184.
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Analysis
by VulDB Data Team • 09/30/2022
The Common Log File System CLFS driver vulnerability represents a critical privilege escalation flaw in multiple Microsoft Windows operating systems including Vista SP2 through Windows 10 version 1607 and Windows Server 2016. This vulnerability resides within the Windows kernel-mode driver responsible for managing common log file system operations, which are essential components for various system logging and transactional processes. The flaw allows local attackers with standard user privileges to execute malicious code that can elevate their access level to SYSTEM, effectively compromising the entire operating system. The vulnerability is particularly concerning because it affects a wide range of Windows versions spanning several years of Microsoft's product lifecycle, making it a persistent threat across enterprise environments.
The technical implementation of this privilege escalation vulnerability stems from improper input validation and inadequate access control mechanisms within the CLFS driver. When a crafted application interacts with the driver through specific API calls, it can manipulate kernel memory structures and bypass security checks that should normally prevent non-privileged users from accessing sensitive system resources. This flaw operates at the kernel level where the driver processes log file operations, allowing attackers to manipulate file handles, memory mappings, and system resource allocations in ways that violate normal security boundaries. The vulnerability specifically affects how the driver handles certain file operations and buffer management, creating opportunities for attackers to exploit memory corruption patterns that lead to privilege escalation. According to CWE standards, this represents a weakness in the validation of input parameters and improper access control mechanisms.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete system compromise capabilities that can be leveraged for persistent access, data exfiltration, and further exploitation. Once elevated to SYSTEM privileges, an attacker can modify system files, install rootkits, disable security features, and establish backdoors that persist across system reboots. The vulnerability's presence across multiple Windows versions means that organizations cannot rely on simple OS version checks to determine exposure, requiring comprehensive patch management strategies. Attackers can exploit this vulnerability through various vectors including malicious applications, compromised software installations, or social engineering campaigns that trick users into executing crafted code. The attack surface is particularly large because CLFS operations are frequently used by legitimate system processes, making the vulnerability harder to detect through traditional monitoring approaches.
Mitigation strategies for this vulnerability require immediate patch deployment across all affected systems, as Microsoft released security updates addressing the specific kernel-mode flaws in the CLFS driver. Organizations should implement comprehensive monitoring for unusual system activity patterns that might indicate exploitation attempts, particularly around file system operations and memory access patterns. Network segmentation and privilege separation can help limit the impact if exploitation occurs, while endpoint protection solutions should be configured to detect and block suspicious API calls to the vulnerable driver. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting kernel-mode exploits that leverage driver vulnerabilities. Regular security assessments should verify that systems are properly patched and that no unauthorized modifications exist in critical system components. Additionally, implementing least privilege principles and maintaining current antivirus signatures can provide additional defense layers against exploitation attempts.