CVE-2018-8440 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists when Windows improperly handles calls to Advanced Local Procedure Call (ALPC), aka "Windows ALPC Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers.
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Analysis
by VulDB Data Team • 02/07/2025
The vulnerability identified as CVE-2018-8440 represents a critical elevation of privilege flaw within the Windows operating system's implementation of Advanced Local Procedure Call mechanisms. This weakness specifically manifests in how Windows processes ALPC calls, creating an opportunity for malicious actors to escalate their privileges from standard user level to system level access. The vulnerability affects a broad range of Windows operating systems including legacy versions like Windows 7, Windows Server 2008, and Windows Server 2008 R2, as well as more recent releases such as Windows 10 and Windows Server 2016, demonstrating the widespread impact across the Windows ecosystem. The flaw stems from improper validation and handling of ALPC communication channels, which are fundamental components used for inter-process communication within the Windows kernel.
Technical exploitation of this vulnerability occurs through crafted ALPC messages that manipulate the kernel's handling of process privileges during inter-process communication operations. When Windows processes these malformed ALPC calls, the system fails to properly validate the security context of the calling process, allowing an attacker to potentially bypass security restrictions and execute code with elevated privileges. This represents a classic kernel-level vulnerability that leverages the inherent trust relationships within the Windows security model. The vulnerability is particularly concerning because ALPC is extensively used throughout the Windows operating system for legitimate system operations, making exploitation more likely to succeed in real-world scenarios. According to CWE classification, this maps to CWE-264, which deals with permissions, privileges, and access control issues, specifically focusing on improper handling of privilege escalation mechanisms.
The operational impact of CVE-2018-8440 extends beyond simple privilege escalation, as successful exploitation can enable attackers to gain complete system control, install malicious software, modify critical system files, and access sensitive data. Attackers can leverage this vulnerability to establish persistent backdoors, escalate privileges to SYSTEM level access, and potentially move laterally within network environments. The vulnerability's presence in both client and server operating systems means that organizations face risks across their entire infrastructure, from desktop computers to critical server environments. Security researchers have noted that this vulnerability can be exploited through various attack vectors including malicious applications, compromised websites, or spear-phishing campaigns that trick users into executing specially crafted payloads. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the 'Windows Admin Rights' and 'System Service Permissions' tactics.
Mitigation strategies for CVE-2018-8440 primarily focus on applying Microsoft's official security patches and updates, which address the underlying ALPC handling issues. Organizations should prioritize immediate patch deployment across all affected Windows systems, particularly those running legacy operating systems that may not receive extended support. Additional protective measures include implementing application whitelisting policies, restricting user privileges, and monitoring for unusual ALPC activity in system logs. Network segmentation and intrusion detection systems can help identify exploitation attempts, while regular security assessments should verify that systems remain protected against this and similar vulnerabilities. The vulnerability underscores the importance of maintaining current security patches and demonstrates how even fundamental system components like ALPC can contain critical security flaws that require continuous monitoring and remediation efforts.