CVE-2007-3533 in 3NJ220
Summary
by MITRE
The 3Com IntelliJack Switch NJ220 before 2.0.23 allows remote attackers to cause a denial of service (reboot and reporting outage) via a loopback packet with zero in the length field.
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Analysis
by VulDB Data Team • 03/02/2018
The vulnerability identified as CVE-2007-3533 affects the 3Com IntelliJack Switch NJ220 series operating firmware versions prior to 2.0.23. This represents a critical denial of service weakness that can be exploited remotely by malicious actors to disrupt network operations. The switch is designed to manage network traffic and provide connectivity services within enterprise environments, making it a potential target for attackers seeking to compromise network availability. The flaw manifests when the device receives a specially crafted loopback packet containing a zero value in the length field, which triggers an unexpected behavior in the packet processing mechanism.
The technical root cause of this vulnerability lies in the insufficient input validation and error handling within the network switch's packet processing engine. When the switch encounters a loopback packet with a zero length field, the device fails to properly validate this malformed input before attempting to process it. This lack of proper sanitization allows the malformed packet to propagate through the system's network stack, ultimately causing the switch to enter an unstable state that results in system reboot. The vulnerability demonstrates a classic weakness in protocol implementation where the device does not adequately handle edge cases or malformed data inputs, leading to system instability.
The operational impact of this vulnerability extends beyond simple service disruption as it can cause significant network outages and reporting failures within the affected environment. When the switch reboots due to the malformed packet, all network connectivity managed by that device is temporarily lost, potentially affecting multiple network segments and services dependent on the switch's functionality. The reporting outage component indicates that the device's management capabilities are also compromised, preventing network administrators from monitoring or managing the affected switch during the outage period. This dual impact on both network connectivity and management functions makes the vulnerability particularly dangerous in production environments where reliability and continuous operation are critical.
Network security practitioners should consider this vulnerability in the context of broader denial of service attack patterns and the specific threat landscape surrounding network infrastructure devices. The flaw aligns with CWE-129, which addresses improper validation of input length fields, and can be categorized under ATT&CK technique T1499.1 for network denial of service attacks. Organizations should implement immediate mitigation strategies including firmware updates to version 2.0.23 or later, network segmentation to limit exposure, and monitoring for suspicious loopback traffic patterns. Additionally, network administrators should consider implementing rate limiting and packet filtering rules to prevent malformed loopback packets from reaching the affected switches, while also establishing incident response procedures to quickly address any exploitation attempts.