CVE-2005-4820 in SMC7904WBRA
Summary
by MITRE
SMC Wireless Router model SMC7904WBRA allows remote attackers to cause a denial of service (reboot) by flooding the router with traffic.
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Analysis
by VulDB Data Team • 08/04/2017
The SMC Wireless Router model SMC7904WBRA presents a significant denial of service vulnerability that can be exploited by remote attackers to forcibly reboot the device. This vulnerability stems from the router's insufficient traffic handling mechanisms and lack of proper input validation for network packets. The flaw allows malicious actors to flood the router with excessive traffic patterns that overwhelm the device's processing capabilities, ultimately leading to an unauthorized reboot cycle that disrupts network connectivity for all connected devices.
This vulnerability operates through a classic resource exhaustion attack vector where the router's network stack fails to properly filter or rate-limit incoming traffic. The device lacks adequate traffic shaping or packet inspection capabilities that would normally prevent such flooding attacks from causing system instability. When the router receives a high volume of malformed or excessive network packets, it cannot properly process them within normal operating parameters, resulting in a system crash that triggers an automatic reboot sequence. The attack requires no authentication or specialized knowledge beyond basic network connectivity, making it particularly dangerous as it can be executed by anyone with access to the network.
The operational impact of this vulnerability extends beyond simple service disruption, as it can create cascading effects throughout network infrastructure. When the router reboots, all connected devices lose network connectivity and must reestablish their connections, potentially disrupting critical business operations or services. The frequency of such attacks can also lead to persistent network instability, where the router continuously reboots in response to ongoing traffic flooding, effectively rendering the network unusable. Organizations relying on this router for their network infrastructure face significant risk of unauthorized service interruption and potential data loss during reboot cycles.
Security professionals should consider this vulnerability in the context of CWE-400, which addresses unspecified resource management issues that can lead to denial of service conditions. The flaw also aligns with ATT&CK technique T1499.004 for network denial of service attacks, where adversaries leverage network traffic to exhaust system resources. Mitigation strategies should include implementing network access control lists to filter traffic patterns, configuring rate limiting on incoming packets, and applying firmware updates from the manufacturer when available. Network administrators should also deploy intrusion detection systems to monitor for unusual traffic patterns that may indicate flooding attempts, and consider segmenting network traffic to limit the impact of such attacks on critical infrastructure components.