CVE-2007-2796 in Cadant C3 CMTS
Summary
by MITRE
Arris Cadant C3 CMTS allows remote attackers to cause a denial of service (service termination) via a malformed IP packet with an invalid IP option.
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Analysis
by VulDB Data Team • 10/27/2017
The vulnerability identified as CVE-2007-2796 affects the Arris Cadant C3 Cable Modem Termination System which is a critical piece of infrastructure in cable internet service provider networks. This device serves as the central point for managing and terminating cable modem connections, making it a prime target for attackers seeking to disrupt network services. The flaw manifests when the system receives malformed IP packets containing invalid IP options, which triggers an unexpected behavior leading to service termination. The vulnerability represents a classic denial of service condition where legitimate network operations are disrupted through the exploitation of protocol implementation weaknesses.
The technical root cause of this vulnerability lies in the insufficient validation of IP packet headers within the network processing stack of the C3 CMTS. When the device encounters an IP packet with malformed options field, the system fails to properly handle the invalid data structure and instead crashes or terminates its network services. This improper error handling stems from a lack of robust input validation mechanisms that should filter out malformed packets before they reach critical processing components. The vulnerability specifically targets the IP protocol implementation where the device does not adequately sanitize IP options that may contain unexpected values or malformed structures, causing the system to enter an unrecoverable state.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the reliability and availability of cable internet services for end users. When an attacker successfully exploits this vulnerability, the CMTS device becomes unresponsive, causing all connected cable modems to lose connectivity and resulting in widespread internet outages for customers within the affected network segment. Network administrators face significant challenges in identifying and mitigating such attacks since they often appear as legitimate network failures rather than malicious activity. The vulnerability particularly impacts service providers who rely on continuous network availability for their revenue-generating services, as even brief service interruptions can result in customer dissatisfaction and potential revenue loss.
Mitigation strategies for this vulnerability should focus on implementing comprehensive network security controls that address both the immediate threat and prevent similar issues in the future. Network segmentation and access control measures can help limit the attack surface by restricting direct access to the CMTS device from untrusted networks. Regular firmware updates and security patches from the vendor should be applied promptly to address known vulnerabilities and strengthen the device's protocol handling capabilities. The implementation of intrusion detection systems can help identify suspicious traffic patterns associated with malformed IP packets, while network monitoring tools can alert administrators to service disruptions that may indicate exploitation attempts. Organizations should also consider implementing network access control lists to filter out packets with malformed IP options and establish robust incident response procedures to quickly address exploitation attempts. This vulnerability aligns with CWE-129 which describes improper validation of input, and represents a technique commonly used in the attack pattern category described in ATT&CK tactic TA0043 for resource hijacking through denial of service.