CVE-1999-0665 in Windows
Summary
by MITRE
An application-critical Windows NT registry key has an inappropriate value.
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Analysis
by VulDB Data Team • 04/18/2026
The vulnerability described in CVE-1999-0665 represents a critical configuration issue within the Windows NT operating system registry that fundamentally undermines system security. This flaw specifically targets a Windows NT registry key that contains an inappropriate value, creating a potential security escalation vector that could allow unauthorized access to system resources. The registry in Windows NT serves as the central hierarchical database for storing system configuration settings and options, making it a prime target for attackers seeking to manipulate system behavior. When a critical registry key contains an incorrect value, it can lead to privilege escalation, unauthorized system modifications, or complete system compromise depending on the specific key and its intended function. The vulnerability's classification as application-critical indicates that the improper registry value directly impacts core system functionality and security controls.
The technical implementation of this vulnerability stems from improper registry key configuration during system installation or updates, where a registry value that should contain specific security parameters or access controls has been set to an inappropriate value. This could manifest as a registry key containing a null value when a specific security identifier should be present, or a value that grants excessive permissions to unauthorized users or processes. The Windows NT registry operates under a hierarchical structure where each key contains values that control various system behaviors, and when these values are improperly configured, they can create security holes that persist across system reboots. The vulnerability typically affects system-level processes that rely on these registry values for authentication, authorization, or access control decisions, potentially allowing attackers to bypass security mechanisms or escalate privileges.
The operational impact of this vulnerability extends beyond simple access control failures to encompass broader system integrity and availability concerns. An attacker who successfully exploits this registry configuration flaw could gain elevated privileges, potentially achieving SYSTEM-level access to the Windows NT system. This type of vulnerability is particularly dangerous because it operates at the system level rather than application level, meaning that successful exploitation could result in complete system compromise without requiring additional attack vectors. The persistence of registry-based vulnerabilities makes them especially challenging to detect and remediate, as they can survive system restarts and may not be immediately apparent during routine security scans. Organizations running Windows NT systems were particularly vulnerable to this type of attack, as the operating system's registry-based security model made such configuration issues particularly impactful.
Mitigation strategies for this vulnerability require immediate registry value correction and comprehensive system hardening measures. System administrators must perform detailed registry audits to identify improperly configured keys and verify that all critical registry values contain appropriate security parameters. The recommended approach involves restoring registry keys to their default values or ensuring that any custom configurations adhere to established security baselines. Organizations should implement regular registry monitoring and change management processes to prevent unauthorized modifications to critical system keys. This vulnerability aligns with CWE-276, which addresses improper permissions and access control, and relates to ATT&CK technique T1112, which covers registry run keys and startup folder modifications. The remediation process typically involves applying security patches, conducting registry integrity checks, and implementing access control policies that limit registry modifications to authorized personnel only. Proper configuration management and regular security assessments are essential to prevent recurrence of such registry-based security issues.