CVE-1999-0582 describes a security vulnerability related to the account lockout policy settings in Windows NT and Windows 2000 systems. Specifically, the vulnerability arises when the account lockout parameters—such as lockout duration, threshold for bad logon attempts, and reset time—are configured inappropriately or insecurely. These settings are critical because they govern how the system responds to repeated failed authentication attempts. If the lockout threshold is set too high or disabled, it allows attackers to perform brute-force or password guessing attacks without triggering account lockouts, thereby increasing the risk of unauthorized access. Conversely, if the lockout duration is excessively long or the threshold is set too low, it can lead to denial-of-service conditions where legitimate users are locked out due to accidental or malicious repeated failed attempts. The vulnerability does not directly compromise confidentiality or integrity but impacts availability by potentially enabling denial-of-service scenarios. The CVSS score of 5 (medium severity) reflects this impact, with an attack vector of network (AV:N), low attack complexity (AC:L), no authentication required (Au:N), and no impact on confidentiality or integrity but partial impact on availability (A:P). No patches are available for this vulnerability, and there are no known exploits in the wild, likely due to the age of the affected systems and the nature of the vulnerability being a configuration weakness rather than a software flaw. However, misconfigured account policies remain a relevant security concern in legacy environments or systems still running Windows 2000 or NT.

For European organizations, the primary impact of this vulnerability lies in the potential for denial-of-service attacks against user accounts, which can disrupt business operations by locking out legitimate users. This can be particularly problematic in environments where Windows 2000 or NT systems are still in use, such as legacy industrial control systems, older financial or governmental infrastructures, or specialized applications that have not been updated. While the vulnerability does not allow direct unauthorized access or data breaches, the availability disruption can lead to operational downtime, reduced productivity, and increased support costs. Additionally, attackers could exploit weak lockout policies to perform brute-force attacks, potentially gaining unauthorized access if other security controls are weak. Given the age of the affected products, most modern European organizations will have migrated away from these systems, but sectors with legacy dependencies remain at risk. The vulnerability also highlights the importance of proper account policy configuration as part of a broader security posture.

Since no patches are available for this vulnerability, mitigation must focus on proper configuration and compensating controls. Organizations should: 1) Review and enforce strict account lockout policies, setting reasonable thresholds for failed login attempts (e.g., 3-5 attempts) and appropriate lockout durations (e.g., 15-30 minutes) to balance security and usability. 2) Implement monitoring and alerting for repeated failed login attempts to detect potential brute-force attacks early. 3) Where possible, upgrade or migrate legacy Windows NT/2000 systems to supported versions with improved security features. 4) Employ multi-factor authentication (MFA) to reduce reliance on password strength and mitigate brute-force risks. 5) Segment legacy systems from critical network segments to limit exposure. 6) Conduct regular security audits of account policies and authentication mechanisms. 7) Educate administrators on the risks of improper lockout settings and ensure policies are documented and enforced consistently.