CVE-2005-0494 in Cable Modem
Summary
by MITRE
The RgSecurity form in the HTTP server for the Thomson TCW690 cable modem running firmware 2.1 and software ST42.03.0a does not properly validate the password before performing changes, which allows remote attackers on the LAN to gain access via a direct POST request.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/09/2024
The vulnerability identified as CVE-2005-0494 resides within the Thomson TCW690 cable modem's HTTP server implementation, specifically targeting the RgSecurity form functionality. This issue represents a classic authentication bypass vulnerability that affects firmware version 2.1 and software version ST42.03.0a of the device. The flaw manifests when the web-based administrative interface processes password change requests without adequate validation of the submitted credentials, creating a significant security gap that can be exploited by unauthorized users within the local network.
The technical implementation of this vulnerability stems from insufficient input validation within the HTTP server's authentication handling mechanism. When a remote attacker with access to the local area network submits a direct POST request to modify security settings, the system fails to verify whether the provided password meets the required complexity criteria or whether the user possesses legitimate authorization to make such changes. This weakness directly maps to CWE-287, which addresses improper authentication issues in software systems, specifically focusing on the absence of proper credential validation mechanisms. The vulnerability essentially allows any LAN-connected attacker to modify administrative passwords without proper authentication, fundamentally undermining the device's security posture.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables attackers to gain full administrative control over the cable modem's configuration settings. Once an attacker successfully exploits this flaw, they can modify network parameters, change user accounts, disable security features, and potentially redirect network traffic. This compromise affects the entire local network infrastructure, as the cable modem serves as a critical gateway device for internet connectivity. The vulnerability is particularly dangerous because it requires minimal privileges to exploit - only local network access is needed, making it accessible to attackers who have already breached the network perimeter through other means such as phishing attacks or compromised endpoints.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and T1566 which addresses credential harvesting. The attack vector represents a lateral movement opportunity where an attacker who has already established a foothold on the LAN can leverage this weakness to escalate privileges and gain persistent access to the network infrastructure. The vulnerability's exploitation does not require specialized tools or advanced technical knowledge, making it particularly attractive to threat actors seeking quick and effective methods to compromise network devices. Organizations should consider implementing network segmentation and access controls to limit the potential damage from such vulnerabilities, while also ensuring that all network devices receive timely firmware updates to address known security issues.
The remediation approach for this vulnerability requires immediate firmware updates from Thomson to address the authentication validation flaw. Network administrators should also implement additional security controls such as restricting direct access to administrative interfaces, implementing network access control lists, and monitoring for unusual administrative activities. Regular vulnerability assessments of network infrastructure devices are essential to identify similar authentication bypass issues that may exist in other network equipment. The vulnerability demonstrates the critical importance of proper input validation and authentication mechanisms in embedded network devices, particularly those that serve as gateways between internal networks and external internet services.