CVE-1999-0791 in Cable Modem
Summary
by MITRE
Hybrid Network cable modems do not include an authentication mechanism for administration, allowing remote attackers to compromise the system through the HSMP protocol.
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Analysis
by VulDB Data Team • 08/15/2024
The vulnerability identified as CVE-1999-0791 represents a critical security flaw in hybrid network cable modems that lack proper authentication mechanisms for administrative access. This weakness specifically affects the HSMP protocol which governs communication between the modem and network management systems. The absence of authentication controls creates an exploitable condition where remote attackers can gain unauthorized administrative access to modem configurations without proper credentials or authorization. The vulnerability stems from the fundamental design flaw in early broadband modem implementations where security considerations were not adequately addressed during the development lifecycle. This issue was particularly significant given the widespread deployment of cable modems in residential and small business environments during the late 1990s and early 2000s.
The technical implementation of this vulnerability involves the HSMP protocol operating without any form of authentication or encryption for administrative commands. When administrators or network management systems attempt to configure or monitor the modem, the HSMP protocol accepts commands without verifying the identity of the sender or ensuring proper authorization levels. This creates a scenario where any remote attacker who can establish communication with the modem's management interface can execute administrative functions including changing network settings, modifying user accounts, disabling security features, or accessing sensitive network information. The flaw operates at the network protocol level and affects the modem's management interface which typically operates on specific port numbers and uses proprietary command sets. According to CWE classification, this vulnerability maps to CWE-287 which describes improper authentication issues in network protocols, and aligns with ATT&CK technique T1072 for software deployment tools.
The operational impact of CVE-1999-0791 extends beyond simple unauthorized access to encompass significant network compromise potential and data exposure risks. Remote attackers can exploit this vulnerability to establish persistent access to network infrastructure, potentially enabling them to redirect traffic, monitor network communications, or serve as a foothold for further attacks within the network. The vulnerability affects both residential and enterprise deployments where cable modems serve as primary network gateways, making it particularly dangerous for organizations that rely on cable internet services. Attackers can leverage this weakness to perform reconnaissance activities, gather network topology information, or establish command and control channels. The lack of authentication also means that multiple unauthorized users could potentially access the same administrative interface simultaneously, creating confusion and complicating incident response efforts. This vulnerability directly impacts the CIA triad by compromising confidentiality through unauthorized data access, integrity through unauthorized configuration changes, and availability through potential service disruption.
Mitigation strategies for CVE-1999-0791 require both immediate and long-term approaches to address the fundamental authentication deficiency. Organizations should implement network segmentation to isolate modem management interfaces from general network traffic, utilizing firewalls to restrict access to management ports and IP addresses. Network administrators should disable unused management protocols and services whenever possible, and implement strict access control lists to limit which systems can communicate with the modem's administrative interface. The most effective long-term solution involves upgrading to modern modems that implement proper authentication mechanisms including strong password policies, encrypted communications, and role-based access controls. Security patches and firmware updates from vendors should be applied immediately when available, though many legacy devices may no longer receive support. Network monitoring should include detection of unauthorized access attempts to modem management interfaces, and regular security audits should verify that administrative access controls remain properly configured. According to industry best practices, this vulnerability demonstrates the critical importance of implementing defense-in-depth strategies and proper network architecture design that considers authentication requirements from the initial system design phase rather than as an afterthought.