CVE-2018-8347 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists in Microsoft Windows when the Windows kernel fails to properly handle parsing of certain symbolic links, aka "Windows Kernel Elevation of Privilege Vulnerability." This affects Windows Server 2016, Windows 10, Windows 10 Servers.
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Analysis
by VulDB Data Team • 07/15/2024
The vulnerability described in CVE-2018-8347 represents a critical elevation of privilege flaw within the Windows kernel that stems from improper handling of symbolic link parsing operations. This weakness allows authenticated attackers with low-privilege user accounts to escalate their privileges and gain system-level access to affected Windows systems. The vulnerability specifically impacts Windows Server 2016, Windows 10, and Windows 10 Servers, making it a widespread concern across modern Windows environments. The flaw resides in the kernel-mode components responsible for processing symbolic links, which are essential file system constructs that provide alternative names for files and directories.
The technical implementation of this vulnerability involves the Windows kernel's insufficient validation and processing of symbolic link structures during file system operations. When the kernel encounters certain malformed or specially crafted symbolic links, it fails to properly validate the link targets and resolve them according to security boundaries. This improper parsing allows an attacker to manipulate the kernel's behavior and potentially bypass security mechanisms that should prevent privilege escalation. The vulnerability is classified as a kernel-level flaw because it operates within the most privileged execution context of the operating system, where it can directly interact with system resources and memory management components.
From an operational impact perspective, this vulnerability creates a significant security risk for organizations relying on Windows infrastructure, as it enables attackers to move from a standard user account to a system administrator level without requiring additional credentials or exploitation of other vulnerabilities. The attack surface is particularly concerning because it can be leveraged by malicious actors who have already gained access to a user account through other means such as phishing attacks, credential theft, or social engineering. Once exploited, the vulnerability allows complete system compromise, enabling attackers to install malware, modify system files, access sensitive data, and potentially establish persistent access to the compromised systems.
Security professionals should implement multiple layers of defense to mitigate this vulnerability, including immediate deployment of Microsoft security patches and updates that address the kernel parsing flaw. Organizations must also enforce strict access controls and monitor for anomalous file system operations that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and follows patterns consistent with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation." Additionally, this vulnerability demonstrates characteristics of improper input validation and privilege management, which are commonly addressed through secure coding practices and runtime protection mechanisms. Network segmentation and principle of least privilege should be enforced to limit the potential damage from successful exploitation attempts.