CVE-2001-0773 in 3220-H DSL Router
Summary
by MITRE
Cayman 3220-H DSL Router 1.0 allows remote attacker to cause a denial of service (crash) via a series of SYN or TCP connect requests.
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Analysis
by VulDB Data Team • 12/15/2024
The CVE-2001-0773 vulnerability affects the Cayman 3220-H DSL Router version 1.0, representing a classic denial of service flaw that exploits TCP connection handling mechanisms. This vulnerability demonstrates a fundamental weakness in the router's network stack implementation where the device fails to properly manage incoming TCP connections, specifically when processing a series of SYN or TCP connect requests. The flaw exists in the router's TCP/IP protocol stack implementation, which does not adequately validate or limit the rate of incoming connection attempts, making it susceptible to exploitation by remote attackers.
The technical nature of this vulnerability stems from improper handling of TCP connection states within the router's operating system. When multiple SYN packets or TCP connect requests are sent in rapid succession to the router, the device's TCP stack becomes overwhelmed and fails to maintain proper connection tracking. This results in the router crashing or becoming unresponsive, effectively rendering the network services unavailable to legitimate users. The vulnerability operates at the transport layer of the OSI model and specifically targets the TCP handshake process, which is fundamental to network communication. This type of vulnerability is categorized under CWE-119 as improper handling of network protocol states and can be classified as a resource exhaustion attack pattern.
The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise network availability and potentially impact business continuity for organizations relying on the affected router. Remote attackers can exploit this vulnerability without requiring authentication, making it particularly dangerous as it can be triggered from anywhere on the internet. The attack vector demonstrates how poorly implemented network stack components can create single points of failure in network infrastructure devices. This vulnerability also aligns with ATT&CK technique T1498 which covers network denial of service attacks, and T1595 which involves network scanning and reconnaissance activities that could precede such attacks.
Mitigation strategies for this vulnerability should include implementing rate limiting mechanisms at the network perimeter to prevent excessive TCP connection attempts from reaching the affected router. Network administrators should consider updating to newer firmware versions that address the TCP stack implementation issues, though this particular router model is likely end-of-life and may not receive updates. Network segmentation and firewall rules can help limit the exposure of the vulnerable device to external threats. The implementation of TCP SYN cookies or similar mechanisms at the network level can provide additional protection against such attacks. Regular network monitoring should be implemented to detect unusual connection patterns that might indicate exploitation attempts, and incident response procedures should be established to quickly address any service disruptions caused by this vulnerability. Organizations should also consider replacing legacy router models with more modern devices that have better TCP stack implementations and security features.