CVE-2008-1523 in ZyNOS
Summary
by MITRE
ZyXEL Prestige routers, including P-660, P-661, and P-662 models with firmware 3.40(AGD.2) through 3.40(AHQ.3), allow remote authenticated users to obtain ISP and Dynamic DNS credentials by sending a direct request for (1) WAN.html, (2) wzPPPOE.html, and (3) rpDyDNS.html, and then reading the HTML source.
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Analysis
by VulDB Data Team • 09/20/2018
The vulnerability identified as CVE-2008-1523 affects ZyXEL Prestige series routers, specifically models P-660, P-661, and P-662, when operating with firmware versions ranging from 3.40(AGD.2) through 3.40(AHQ.3). This represents a critical information disclosure flaw that undermines the security posture of network infrastructure devices. The vulnerability stems from the router's web-based management interface failing to properly validate authentication status when serving specific HTML configuration pages, allowing authenticated attackers to directly access sensitive credential information without proper authorization mechanisms.
The technical implementation of this vulnerability involves the router's web server component serving configuration pages that contain plaintext credentials for ISP connections and Dynamic DNS services. When an authenticated user sends direct HTTP requests to specific endpoints including WAN.html, wzPPPOE.html, and rpDyDNS.html, the router responds with HTML content that includes unencrypted username and password values. This occurs because the web interface lacks proper access control checks for these administrative configuration pages, creating a path for credential extraction that bypasses normal user authentication flows. The vulnerability is classified under CWE-200 as information exposure, specifically related to the disclosure of sensitive information through improper access control.
The operational impact of this vulnerability extends beyond simple credential theft, as it provides attackers with the means to establish unauthorized network connectivity and potentially gain persistent access to the network infrastructure. Once credentials are obtained, attackers can configure the router to redirect traffic through malicious endpoints, modify network settings, or establish backdoor connections that persist beyond the initial compromise. This vulnerability directly impacts the principle of least privilege and violates fundamental security requirements for network device management interfaces. The threat actors can leverage this weakness to perform reconnaissance activities, conduct man-in-the-middle attacks, or use the stolen credentials for lateral movement within the network. According to ATT&CK framework, this vulnerability maps to T1566 (Phishing) and T1071.004 (Application Layer Protocol: DNS) as attackers can use the stolen credentials to manipulate DNS settings and establish persistent network access.
Mitigation strategies for this vulnerability require immediate firmware updates from ZyXEL to address the improper access control mechanisms in the web interface. Network administrators should also implement network segmentation to limit access to router management interfaces and ensure that only authorized personnel can reach these administrative endpoints. Additional protective measures include configuring firewalls to restrict access to router management ports, implementing strong authentication mechanisms with multi-factor authentication, and regularly auditing router configurations for unauthorized changes. The vulnerability highlights the importance of secure web application development practices and proper input validation in network device interfaces, as outlined in industry standards such as NIST SP 800-53 and ISO/IEC 27001. Organizations should also conduct regular vulnerability assessments of network infrastructure devices and maintain up-to-date patch management procedures to prevent exploitation of known vulnerabilities.