CVE-2005-4275 in DPX2100 Cable Modem
Summary
by MITRE
Scientific Atlanta DPX2100 Cable Modem allows remote attackers to cause a denial of service (device crash) via an IP packet with the same source and destination IPs and ports, and with the SYN flag set (aka LanD), as demonstrated using hping2. NOTE: the provenance of this issue is unknown; the details are obtained solely from third party information.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/07/2024
The CVE-2005-4275 vulnerability affects the Scientific Atlanta DPX2100 Cable Modem, representing a significant network infrastructure weakness that enables remote attackers to execute denial of service attacks. This vulnerability specifically targets the modem's handling of malformed IP packets, exploiting a fundamental flaw in its packet processing logic. The attack vector involves sending specially crafted IP packets where the source and destination IP addresses and ports are identical, combined with the SYN flag set, creating what is known as the LanD attack pattern. This particular variant of denial of service attack leverages the TCP three-way handshake mechanism in an unconventional manner to trigger device instability.
The technical flaw resides in the modem's failure to properly validate incoming IP packets before processing them through the TCP connection establishment process. When the device receives a packet with identical source and destination fields along with the SYN flag, it enters an undefined state where normal processing routines fail. This condition causes the modem's TCP stack implementation to crash or become unresponsive, effectively rendering the network connection unavailable to legitimate users. The vulnerability demonstrates a classic buffer overflow or state machine handling weakness where the device does not adequately sanitize input parameters, particularly those related to network address and port information.
Operationally, this vulnerability presents a serious threat to network availability and service continuity, especially in environments where cable modems serve as critical access points for internet connectivity. The LanD attack can be executed remotely without requiring authentication or specialized equipment beyond basic network tools like hping2, making it particularly dangerous for widespread exploitation. Network administrators face the challenge of detecting such attacks, as they appear to be legitimate network traffic patterns that are simply malformed in a specific way. The impact extends beyond individual device compromise to potentially affect larger network segments if multiple modems in a network are vulnerable to the same attack pattern.
Mitigation strategies for CVE-2005-4275 should focus on network-level defenses and device-specific updates. Network administrators can implement firewall rules to block packets with identical source and destination addresses, effectively preventing the attack vectors from reaching vulnerable modems. Additionally, configuring intrusion detection systems to monitor for these specific packet patterns can provide early warning of attempted attacks. Device vendors should prioritize firmware updates that address the underlying TCP stack implementation issues, ensuring proper validation of packet headers before processing. This vulnerability aligns with CWE-129, which covers improper validation of input, and relates to ATT&CK technique T1498, which covers network denial of service attacks. Organizations should also consider implementing network segmentation to limit the potential impact of such attacks and establish monitoring procedures to detect anomalous network behavior that might indicate exploitation attempts.