CVE-2000-0771 in Windows
Summary
by MITRE
Microsoft Windows 2000 allows local users to cause a denial of service by corrupting the local security policy via malformed RPC traffic, aka the "Local Security Policy Corruption" vulnerability.
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Analysis
by VulDB Data Team • 06/25/2021
The vulnerability identified as CVE-2000-0771 represents a critical flaw in Microsoft Windows 2000 operating systems that enables local attackers to execute denial of service attacks through manipulation of local security policy settings. This vulnerability specifically targets the Windows RPC (Remote Procedure Call) infrastructure and exploits weaknesses in how the system processes malformed RPC traffic directed at local security policy components. The flaw exists within the core security subsystem of Windows 2000, making it particularly dangerous as it can be leveraged by any user with local access to the system. According to CWE-119, this vulnerability falls under memory corruption issues where improper handling of input data leads to system instability and potential complete service disruption. The ATT&CK framework categorizes this under privilege escalation and denial of service tactics, as local users can exploit this weakness to compromise system availability.
The technical implementation of this vulnerability involves the exploitation of RPC communication channels that handle local security policy modifications. When malformed RPC packets are sent to the Windows security policy service, the system fails to properly validate or sanitize the incoming data structures, leading to memory corruption within the security policy management components. This corruption can cause the security policy service to crash or become unresponsive, effectively rendering the local security management functionality inoperable. The flaw typically manifests when the system attempts to process malformed security policy data through RPC interfaces, causing buffer overflows or invalid memory access patterns that trigger system instability. The vulnerability is particularly concerning because it operates at the kernel level within Windows 2000's security architecture, making it difficult to detect and mitigate through standard user-level security measures.
The operational impact of CVE-2000-0771 extends beyond simple denial of service conditions to potentially compromise the entire security posture of affected systems. When the local security policy becomes corrupted, users may lose access to critical security features such as account management, password policies, and access control mechanisms. This vulnerability can be exploited by local users who have minimal system privileges, making it particularly dangerous in multi-user environments where unauthorized individuals might gain access to legitimate accounts. The attack vector requires only local system access, meaning that any user with login credentials can potentially trigger the vulnerability, making it an attractive target for both malicious insiders and attackers who have gained initial access to a system. The disruption can be severe enough to require system reboot or manual security policy restoration, causing significant downtime and operational disruption for affected organizations.
Mitigation strategies for this vulnerability should focus on both immediate protective measures and long-term system hardening approaches. Microsoft released patches and updates to address this specific vulnerability, and system administrators should ensure that all Windows 2000 systems are updated with the latest security patches. Network segmentation and access control measures can help limit the potential impact by restricting local access privileges to critical system components. Implementing monitoring solutions that detect unusual RPC traffic patterns or security policy modification attempts can provide early warning of potential exploitation attempts. Security awareness training for system administrators and users can help identify suspicious activities that might indicate exploitation attempts. Additionally, organizations should consider implementing intrusion detection systems that can monitor for the specific RPC traffic patterns associated with this vulnerability. The vulnerability demonstrates the importance of proper input validation and memory management in security-critical system components, aligning with best practices outlined in both CWE guidelines and industry security frameworks that emphasize robust error handling and data validation mechanisms to prevent similar issues in future system implementations.