CVE-2008-1529 in ZyNOS
Summary
by MITRE
ZyXEL Prestige routers have a minimum password length for the admin account that is too small, which makes it easier for remote attackers to guess passwords via brute force methods.
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Analysis
by VulDB Data Team • 09/20/2018
The CVE-2008-1529 vulnerability affects ZyXEL Prestige series routers where the administrative account password policy enforcement is insufficiently configured. This weakness stems from the router firmware implementation that allows administrative passwords with lengths below the recommended security thresholds, creating a significant attack surface for malicious actors. The vulnerability specifically targets the authentication mechanism of these network devices, which are commonly deployed in residential and small business environments where security awareness may be limited. The affected routers typically implement a default password policy that permits passwords as short as four characters, which represents a critical failure in security design principles and violates established best practices for credential strength requirements.
The technical flaw manifests in the router's web-based administration interface where password validation occurs. When administrators configure passwords for the admin account, the system accepts credentials that are too short to provide adequate protection against automated attack methodologies. This weakness enables remote attackers to conduct brute force password guessing attacks with significantly reduced computational requirements and time investment. The vulnerability operates at the application layer of the network stack, specifically within the authentication service component that handles user credentials for administrative access. Attackers can leverage readily available tools to rapidly cycle through common password combinations or employ dictionary attacks against the weak credential structure, exploiting the minimal entropy provided by short passwords.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass broader network compromise potential. Once an attacker successfully guesses or cracks the administrative password, they gain complete control over the router configuration, enabling them to modify firewall rules, change DNS settings, redirect traffic, and potentially establish persistent backdoors within the network infrastructure. This access allows malicious actors to perform man-in-the-middle attacks, monitor network traffic, and use the compromised router as a launch point for further attacks against internal network resources. The vulnerability particularly affects organizations that rely on default configurations without implementing proper security hardening measures, creating a persistent risk that can remain undetected for extended periods. Network administrators may not immediately recognize the compromise due to the subtle nature of router-level attacks compared to more visible network intrusions.
Mitigation strategies for CVE-2008-1529 require immediate implementation of enhanced password policies and administrative access controls. Organizations should enforce minimum password length requirements of at least eight characters with mixed character sets including uppercase, lowercase, numbers, and special characters. The router firmware should be updated to versions that properly enforce strong password policies and reject weak credentials during configuration. Network segmentation and access control measures should be implemented to limit administrative access to authorized personnel only, while disabling unnecessary services and remote management capabilities. Regular security audits should verify that password policies are properly enforced and that administrative accounts are not using default or weak credentials. This vulnerability aligns with CWE-521 Weak Password Requirements and maps to ATT&CK technique T1110.001 Brute Force: Password Guessing, highlighting the importance of proper credential strength enforcement in network device security. Additionally, organizations should implement network monitoring solutions to detect unusual administrative access patterns and establish incident response procedures for rapid remediation of compromised devices.