CVE-2000-0377 in Windows
Summary
by MITRE
The Remote Registry server in Windows NT 4.0 allows local authenticated users to cause a denial of service via a malformed request, which causes the winlogon process to fail, aka the "Remote Registry Access Authentication" vulnerability.
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Analysis
by VulDB Data Team • 10/16/2025
The vulnerability identified as CVE-2000-0377 represents a critical weakness in the Windows NT 4.0 operating system's remote registry service implementation. This flaw specifically targets the remote registry server component that enables administrators to manage registry settings across networked systems. The vulnerability stems from inadequate input validation within the registry service's processing of remote requests, creating an exploitable condition that can be leveraged by authenticated local users to disrupt system operations. The remote registry service in Windows NT 4.0 was designed to facilitate administrative tasks across network boundaries, but this particular implementation contained a significant security gap that allowed for malicious manipulation of registry access requests. The flaw operates at the system level where registry service requests are processed, making it particularly dangerous as it can be exploited by users who already possess legitimate authentication credentials to the system.
The technical mechanism behind this vulnerability involves the remote registry server's failure to properly validate incoming requests when processing registry access operations. When a malformed registry request is submitted to the remote registry service, the system's processing logic does not adequately sanitize the input parameters, leading to a condition where the winlogon process becomes unstable and eventually fails. This occurs because the malformed request triggers an unexpected execution path within the registry service code, causing memory corruption or resource exhaustion that ultimately results in the winlogon process termination. The vulnerability is classified as a denial of service condition because it prevents legitimate users from accessing the system's registry services, effectively blocking administrative access and potentially disrupting system functionality. This type of vulnerability falls under the CWE-122 category of "Heap-based Buffer Overflow" or similar memory corruption issues, where improper input validation leads to system instability. The attack vector requires local authentication access, making it a privilege escalation vulnerability that can be exploited by users who already have legitimate system credentials, though the impact extends beyond the immediate user to affect the entire system's registry access functionality.
The operational impact of CVE-2000-0377 extends beyond simple service disruption to potentially compromise system availability and administrative capabilities. When the winlogon process fails due to this vulnerability, users lose access to the system's core authentication mechanisms, creating a cascading effect that can prevent legitimate administrative access to the system. This vulnerability particularly affects enterprise environments where Windows NT 4.0 systems may be running critical applications or services that depend on registry access for proper operation. The denial of service condition can be sustained if the vulnerability is repeatedly exploited, potentially requiring system restarts to restore normal operations. From an attacker's perspective, this vulnerability represents a low-effort method to disrupt system availability without requiring extensive privileges or complex exploitation techniques. The vulnerability's impact aligns with ATT&CK technique T1489 which describes creating or manipulating system services to deny access to resources, and T1070 which covers indicator removal through system cleanup or process termination. Organizations running Windows NT 4.0 systems were particularly vulnerable to this attack as the platform lacked modern security features and regular patching mechanisms that would have prevented such exploitation.
Mitigation strategies for this vulnerability primarily focus on implementing proper access controls and system hardening measures. The most effective immediate solution involves disabling the remote registry service when it is not actively required for administrative tasks, as this eliminates the attack surface entirely. System administrators should also implement strict access controls to limit local authentication privileges to only those users who require them for legitimate administrative purposes. Network segmentation and firewall rules can help prevent unauthorized access to the registry service ports, though this is secondary to proper local access controls. Microsoft released patches for this vulnerability as part of their regular security updates, but organizations running legacy Windows NT 4.0 systems needed to carefully evaluate their upgrade paths due to the platform's end-of-life status. The vulnerability serves as an important example of why proper input validation and robust error handling are critical in system services, particularly those handling remote requests. Regular system monitoring should include detection of abnormal registry service behavior or winlogon process failures that could indicate exploitation attempts. Security awareness training for system administrators should emphasize the importance of maintaining secure configurations and avoiding unnecessary service exposure. This vulnerability also highlights the importance of the principle of least privilege and demonstrates how even authenticated users with legitimate access can be leveraged to create denial of service conditions that impact system availability and security posture.