CVE-1999-0503 in Windows
Summary
by MITRE
a windows nt local user or administrator account has a guessable password.
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Analysis
by VulDB Data Team • 04/16/2026
This vulnerability represents a fundamental weakness in password security mechanisms within windows nt operating systems where user accounts possess passwords that can be easily guessed through systematic enumeration or dictionary attacks. The issue stems from weak password policies that allow users to select passwords that are either too simple, predictable, or commonly used, creating an attack surface that adversaries can exploit to gain unauthorized access to systems. The vulnerability is classified under cwe-521 weak password requirements, which directly relates to the failure of systems to enforce strong authentication credentials. From an operational perspective this weakness affects both local users and administrators, meaning that even legitimate account holders may have passwords that compromise system integrity, potentially allowing attackers to escalate privileges and gain full control over affected systems. The attack surface extends beyond simple credential guessing to include password spraying techniques where attackers attempt to use common passwords across multiple accounts. This vulnerability aligns with several tactics described in the attack pattern taxonomy including privilege escalation and credential access, making it a critical concern for system administrators who must ensure proper password policies are enforced.
The technical implementation of this vulnerability involves the absence or failure of password strength validation mechanisms within the windows nt authentication framework. Systems running windows nt often default to permissive password policies that do not enforce minimum complexity requirements, length restrictions, or prohibitions against commonly used passwords. This weakness allows attackers to leverage automated tools that systematically test common passwords or employ dictionary attacks against user accounts. The vulnerability is particularly dangerous because it affects both standard user accounts and administrative accounts, meaning that even a single compromised account could provide attackers with elevated privileges. The impact extends to the broader network security posture as compromised accounts can serve as entry points for lateral movement and further exploitation. This weakness also relates to cwe-307 improper restriction of repeated authentication attempts, which can compound the vulnerability by allowing attackers to make multiple password guesses without effective account lockout mechanisms.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term policy enforcement. System administrators should implement strong password policies that enforce minimum length requirements of at least eight characters with complexity requirements including uppercase, lowercase, numeric, and special characters. The implementation of account lockout mechanisms after a specified number of failed authentication attempts provides additional protection against brute force attacks. Regular password audits should be conducted to identify and reset accounts with weak or guessable passwords. Organizations should deploy automated tools to scan for and remediate weak password configurations across their windows nt environments. The use of multi-factor authentication should be considered as an additional layer of protection, though this may not be feasible in all legacy windows nt deployments. Security awareness training for users regarding password selection and the importance of strong authentication credentials should be implemented. These measures align with nist special publication 800-63b guidelines for digital identity management and help ensure that systems maintain adequate security postures against credential-based attacks. The vulnerability serves as a reminder of the critical importance of robust authentication mechanisms and proper password policy enforcement in maintaining system security.