CVE-1999-0507 in Router
Summary
by MITRE
An account on a router, firewall, or other network device has a guessable password.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 04/17/2026
This vulnerability represents a fundamental weakness in network device security where authentication credentials can be easily compromised through brute force or dictionary attacks. The issue stems from weak password policies that allow users to select easily guessable passwords, creating an entry point for unauthorized access to critical network infrastructure. This type of vulnerability directly violates security best practices and can be classified under CWE-521 Weak Password Requirements, which specifically addresses insufficient password strength controls. The vulnerability affects network devices including routers, firewalls, and other security appliances that serve as gateways between internal networks and external threats, making it particularly dangerous in enterprise and critical infrastructure environments.
The technical flaw manifests when network device administrators fail to enforce strong password policies or when default passwords remain unchanged after device installation. Attackers can exploit this weakness using automated tools that rapidly test common password combinations, default credentials, or rainbow table attacks against the authentication system. The vulnerability exists at the authentication layer of network security protocols, where weak credentials bypass proper access controls and allow unauthorized users to gain administrative privileges. This creates a persistent security risk as compromised accounts can provide attackers with continuous access to network resources, enabling them to monitor traffic, modify configurations, or launch further attacks against the internal network. The attack surface is particularly large given that many network devices are deployed in unattended locations and may not receive regular security updates or password changes.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it can lead to complete network compromise and data breaches. Once an attacker gains access through a guessable password, they can manipulate firewall rules to allow malicious traffic, install backdoors, or exfiltrate sensitive information from the network. This vulnerability directly aligns with attack techniques described in the MITRE ATT&CK framework under T1110 Targeted Social Engineering and T1078 Valid Accounts, where adversaries leverage weak credentials to establish persistent access. The risk is amplified in environments where network devices control critical infrastructure, as compromised authentication can lead to denial of service, data manipulation, or complete network takeover. Organizations may experience regulatory compliance violations, financial losses, and reputational damage when such vulnerabilities are exploited, particularly in sectors governed by cybersecurity regulations like healthcare, finance, or critical infrastructure protection standards.
Mitigation strategies must address both immediate remediation and long-term security improvements. Organizations should implement strong password policies that enforce minimum complexity requirements, regular password changes, and account lockout mechanisms after failed authentication attempts. Network administrators must change all default passwords immediately upon device deployment and maintain comprehensive inventories of all network devices and their authentication credentials. The implementation of multi-factor authentication, network segmentation, and regular security audits can significantly reduce the risk associated with weak passwords. Additionally, network devices should be configured to disable unnecessary services and remote access where possible, and administrators should monitor authentication logs for suspicious activity. Regular vulnerability assessments and penetration testing should be conducted to identify and remediate weak password issues across all network infrastructure components, ensuring compliance with industry standards such as NIST SP 800-128 and ISO 27001 requirements for access control and authentication management.