CVE-2004-0900 in Windows
Summary
by MITRE
The DHCP Server service for Microsoft Windows NT 4.0 Server and Terminal Server Edition does not properly validate the length of certain messages, which allows remote attackers to execute arbitrary code via a malformed DHCP message, aka the "DHCP Request Vulnerability."
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Analysis
by VulDB Data Team • 07/07/2025
The DHCP Request Vulnerability identified as CVE-2004-0900 represents a critical buffer overflow flaw in the Microsoft Windows NT 4.0 Server and Terminal Server Edition DHCP Server service implementations. This vulnerability stems from inadequate input validation mechanisms within the DHCP message processing pipeline, specifically failing to properly validate the length of incoming DHCP requests. The flaw exists in the way the system handles DHCP message structures, where the server does not adequately check the boundaries of received data packets before processing them, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized system access.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a malformed DHCP message with oversized or malformed data fields that exceed the expected buffer sizes allocated by the Windows NT 4.0 DHCP server. When the vulnerable service attempts to process this malformed message, the insufficient length validation causes a buffer overflow condition that can be manipulated to overwrite critical memory locations. This memory corruption allows attackers to inject and execute arbitrary code with the privileges of the DHCP server process, typically running with elevated system privileges. The vulnerability specifically affects the DHCP server's handling of certain message parameters, particularly those related to option fields and vendor-specific information, where the server fails to validate that incoming data fits within predetermined buffer limits.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with a potential foothold for broader network compromise within environments relying on Windows NT 4.0 DHCP services. Organizations using this legacy operating system face significant risk since the vulnerability can be exploited without requiring authentication or prior access to the network. The attack vector is particularly dangerous because it can be initiated from any location on the network where the attacker can send DHCP messages, making it a passive threat that doesn't require active network monitoring or complex attack chains. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of improper input validation in network services. The attack can potentially lead to complete system compromise, allowing threat actors to establish persistent access, escalate privileges, or use the compromised system as a launch point for further attacks against other network resources.
Mitigation strategies for this vulnerability must address both immediate protection and long-term remediation. Organizations should implement immediate network segmentation to isolate DHCP services from critical systems and deploy network access control measures that limit DHCP message sources. The most effective immediate solution involves applying Microsoft's security patches and updates, though these may not be available for the legacy Windows NT 4.0 platform. Network administrators should consider implementing DHCP snooping mechanisms and DHCP message filtering to prevent malformed messages from reaching vulnerable servers. Additionally, monitoring and logging of DHCP traffic should be enhanced to detect anomalous message patterns that might indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for remote code execution and T1021.002 for remote services, representing a critical threat that requires both defensive measures and proactive threat hunting activities. The vulnerability also highlights the importance of maintaining up-to-date security patches and the risks associated with running unsupported operating systems in enterprise environments.