CVE-2007-6040 in F5D7230-4
Summary
by MITRE
The Belkin F5D7230-4 Wireless G Router allows remote attackers to cause a denial of service (degraded networking and logging) via a flood of TCP SYN packets, a related issue to CVE-1999-0116.
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Analysis
by VulDB Data Team • 04/12/2019
The Belkin F5D7230-4 Wireless G Router presents a significant vulnerability classified as CVE-2007-6040, which enables remote attackers to execute a denial of service attack through TCP SYN packet flooding. This vulnerability represents a classic implementation flaw in the router's network stack processing capabilities, specifically affecting how the device handles incoming TCP connections. The issue operates under the broader category of TCP SYN flood attacks that exploit the three-way handshake mechanism, where an attacker sends a large volume of SYN requests without completing the handshake process. The router's failure to properly manage these connection attempts results in resource exhaustion and subsequent network degradation. This vulnerability aligns with CWE-400, which catalogs weaknesses related to resource exhaustion, and demonstrates how insufficient input validation and connection handling can compromise system availability. The affected device operates within the consumer-grade networking equipment space, where firmware limitations often prevent proper handling of malicious traffic patterns. The attack vector requires no authentication and can be executed from remote locations, making it particularly dangerous for home and small office environments where such devices are commonly deployed without proper network monitoring or security controls.
The technical exploitation of this vulnerability manifests through the router's inability to properly manage TCP connection requests during the initial handshake phase. When subjected to SYN flood attacks, the router's connection table becomes overwhelmed with half-open connections, causing legitimate network traffic to be delayed or dropped entirely. This results in degraded networking performance where users experience intermittent connectivity issues, slow network speeds, and potential complete network outages. The logging functionality is also impacted, as the router's system resources become saturated with connection attempts, preventing proper logging of legitimate network events or security incidents. The vulnerability demonstrates a fundamental flaw in the device's TCP stack implementation, where proper connection rate limiting and connection tracking mechanisms are either absent or insufficiently configured. This type of attack directly relates to the broader class of DoS attacks that have been documented in various networking standards, including those referenced in the ATT&CK framework under the network denial of service technique. The router's architecture appears to lack proper defense mechanisms against connection exhaustion attacks, which is a common weakness in embedded networking devices that prioritize cost and functionality over security hardening.
The operational impact of this vulnerability extends beyond simple network disruption to potentially compromise the overall security posture of affected networks. When the router becomes unresponsive due to connection flooding, legitimate users cannot establish network connections, and network administrators lose visibility into the device's operational status. The degraded logging capability further compounds the issue by preventing security professionals from identifying attack patterns or conducting forensic analysis of network events. Organizations relying on these devices for network connectivity face significant operational risks, particularly in environments where continuous network availability is critical. The vulnerability affects not only the immediate network performance but also creates potential entry points for more sophisticated attacks, as the compromised router may become a staging ground for further exploitation. This type of vulnerability is particularly concerning in IoT and home networking environments where devices are often left unpatched and are not regularly monitored for security issues. The attack's remote nature means that adversaries can target multiple devices simultaneously without requiring physical access or local network credentials, making the vulnerability particularly dangerous for large deployments.
Mitigation strategies for this vulnerability require both immediate operational responses and longer-term architectural improvements. Network administrators should implement rate limiting and SYN cookie mechanisms at the network perimeter to prevent SYN flood attacks from reaching the affected router. The router's firmware should be updated to the latest available version if such updates exist, though many older consumer devices lack ongoing security support. Network segmentation and access control measures can help isolate affected devices and limit the potential damage from successful attacks. Organizations should also consider implementing intrusion detection systems that can identify and alert on unusual connection patterns or SYN flood activities targeting network devices. The vulnerability highlights the importance of proper device hardening and the need for robust security controls in embedded networking equipment. Security professionals should monitor for signs of exploitation through network traffic analysis and ensure that affected devices are properly configured to minimize their attack surface. Regular vulnerability assessments and network monitoring are essential for identifying and addressing similar weaknesses in other networking equipment within the organization's infrastructure. The incident underscores the necessity of maintaining current security practices and the importance of vendor support lifecycle management for networking equipment.