CVE-2004-0680 in Model 5560 X3 Ethernet ADSL Modem
Summary
by MITRE
Zoom X3 ADSL modem has a terminal running on port 254 that can be accessed using the default HTML management password, even if the password has been changed for the HTTP interface, which could allow remote attackers to gain unauthorized access.
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Analysis
by VulDB Data Team • 07/08/2017
The Zoom X3 ADSL modem represents a significant security vulnerability through its implementation of dual authentication mechanisms that fail to maintain consistency across different administrative interfaces. This device operates with two distinct management interfaces: an HTTP web interface that can be configured with custom passwords and a separate terminal service running on port 254 that remains accessible through a hardcoded default credential. The vulnerability stems from the device's design where the terminal service maintains a static default password regardless of changes made to the HTTP interface credentials, creating a persistent backdoor that attackers can exploit to gain unauthorized access to the device's administrative functions. This flaw directly violates fundamental security principles of credential isolation and consistent access control enforcement that are essential for network device security.
The technical implementation of this vulnerability involves a clear separation between the web-based management interface and the terminal-based service that operates independently of the HTTP authentication system. When administrators modify the HTTP management password through the standard web interface, the terminal service on port 254 continues to accept the default credential, effectively creating a bypass mechanism that undermines the security configuration efforts. This represents a classic case of insecure default configuration where the device fails to properly synchronize authentication states between its various management interfaces. The vulnerability specifically affects the device's ability to maintain consistent access control policies and demonstrates poor separation of concerns in the authentication subsystem.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential network compromise and system exploitation. Remote attackers who discover this weakness can gain administrative privileges on the modem without requiring knowledge of the current HTTP interface password, potentially enabling them to modify network configurations, disable security features, or establish persistent access points within the network infrastructure. The device's role as an ADSL modem makes it a critical network component that, when compromised, can provide attackers with direct control over internet connectivity and network traffic routing. This vulnerability particularly affects organizations that rely on network devices with default credentials that are never properly changed or secured, creating a persistent risk vector that remains exploitable regardless of other security measures implemented.
Security mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements. The primary recommendation involves ensuring that all management interfaces on network devices maintain synchronized authentication mechanisms, with any changes to one interface automatically propagating to all related services. Network administrators should implement comprehensive device inventory management to identify and patch affected devices, while also establishing procedures to verify that default credentials are disabled or changed during initial device deployment. This vulnerability aligns with CWE-798, which specifically addresses the use of hardcoded credentials in software, and represents a typical ATT&CK technique where adversaries leverage weak or default credentials to establish initial access to network infrastructure. Organizations should also implement network segmentation and monitoring to detect unauthorized access attempts to port 254 and other potentially vulnerable management services. The incident highlights the critical importance of proper security configuration management and the necessity of conducting thorough vulnerability assessments across all network device interfaces to prevent similar issues in other network infrastructure components.