CVE-2004-0893 in Windows
Summary
by MITRE
The Local Procedure Call (LPC) interface of the Windows Kernel for Windows NT 4.0, Windows 2000, Windows XP, and Windows Server 2003 does not properly validate the lengths of messages sent to the LPC port, which allows local users to gain privileges, aka "Windows Kernel Vulnerability."
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Analysis
by VulDB Data Team • 03/10/2021
The vulnerability identified as CVE-2004-0893 represents a critical privilege escalation flaw within the Windows kernel's Local Procedure Call interface implementation. This weakness affects multiple operating systems including Windows NT 4.0, Windows 2000, Windows XP, and Windows Server 2003, making it a widespread concern across the Windows ecosystem. The vulnerability stems from inadequate input validation mechanisms within the kernel's LPC message handling subsystem, which processes inter-process communication requests between kernel components and user-mode applications. The flaw specifically manifests when the kernel fails to properly validate the length fields of messages transmitted through LPC ports, creating a potential attack vector for local adversaries.
The technical nature of this vulnerability aligns with CWE-129, which describes improper validation of array index values, and more broadly relates to CWE-125, improper bounds checking in memory operations. The LPC interface serves as a fundamental communication mechanism within Windows kernel space, enabling various system components to exchange information and coordinate operations. When maliciously crafted messages with oversized or malformed length fields are sent to LPC ports, the kernel's insufficient validation allows these malformed inputs to bypass normal security checks. This failure in input sanitization creates opportunities for attackers to manipulate kernel memory structures and potentially execute arbitrary code with elevated privileges. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited to gain SYSTEM-level access, which provides complete control over the affected system.
From an operational perspective, this vulnerability presents a significant risk to organizations running affected Windows versions, as local users can leverage it to escalate their privileges without requiring external network access or sophisticated attack vectors. The attack requires local system access but does not necessitate network connectivity, making it particularly concerning for environments where local access control may be insufficient. Security researchers have documented that this vulnerability can be exploited to execute code with the highest system privileges, effectively granting attackers complete control over the targeted system. The impact extends beyond individual system compromise, as successful exploitation can lead to full network infiltration, data exfiltration, and persistence mechanisms that persist across system reboots. This vulnerability also aligns with ATT&CK technique T1068, which describes exploiting vulnerabilities in the Windows kernel, and T1059, covering execution through system commands, as attackers can leverage the privilege escalation to establish persistent access.
Mitigation strategies for CVE-2004-0893 should focus on immediate patch deployment for all affected Windows versions, as Microsoft released security updates specifically addressing this vulnerability. Organizations should implement comprehensive patch management processes to ensure all systems receive timely security updates, particularly for legacy operating systems that are no longer supported. System administrators should also consider implementing additional security controls such as disabling unnecessary LPC ports, restricting local user access to system resources, and monitoring for unusual LPC activity patterns. Network segmentation and access control measures can help limit the potential impact of exploitation attempts, while regular security audits should verify that systems are not running vulnerable versions of Windows. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the risks associated with running unsupported operating systems, as these legacy versions continue to pose significant security risks long after their official support periods end.