CVE-2004-1502 in 602 Lan Suite
Summary
by MITRE
The Telnet proxy in 602 Lan Suite 2004.0.04.0909 and earlier allows remote attackers to cause a denial of service (socket exhaustion) via a Telnet request to an IP address of the proxy s network interface, which causes a loop.
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Analysis
by VulDB Data Team • 07/15/2017
The vulnerability identified as CVE-2004-1502 affects the Telnet proxy functionality within the 602 Lan Suite 2004.0.04.0909 and earlier versions, representing a significant security flaw that enables remote attackers to execute denial of service attacks through socket exhaustion. This vulnerability specifically targets the proxy component that handles Telnet connections, creating a condition where the system becomes unresponsive due to resource depletion. The flaw manifests when an attacker sends a Telnet request to an IP address associated with the proxy's network interface, triggering an infinite loop that consumes system resources and prevents legitimate connections from being established. The vulnerability stems from inadequate input validation and error handling within the proxy's network processing logic, allowing malicious requests to bypass normal connection handling procedures and create resource consumption loops.
The technical implementation of this vulnerability involves the Telnet proxy's failure to properly validate or limit connection attempts, particularly when processing requests directed toward the proxy's own network interface addresses. When such requests are received, the proxy enters an infinite loop where it continuously attempts to process the malformed connection request, causing socket allocation to rapidly consume available system resources. This behavior directly correlates to CWE-400, which describes unchecked resource consumption vulnerabilities, and represents a classic example of a resource exhaustion attack pattern. The loop mechanism creates a condition where each connection attempt consumes additional socket resources without proper cleanup or termination, leading to progressive system degradation until the service becomes completely unavailable. The vulnerability demonstrates poor defensive programming practices where the proxy lacks proper timeout mechanisms and resource management controls necessary to handle malformed or malicious input.
From an operational impact perspective, this vulnerability creates a severe disruption to network services provided by the 602 Lan Suite, as legitimate users cannot establish Telnet connections to the affected proxy. The socket exhaustion results in cascading failures that can affect other network services running on the same system, as available network resources become depleted and system performance deteriorates significantly. The vulnerability is particularly dangerous because it can be exploited remotely without requiring authentication, making it an attractive target for attackers seeking to disrupt network operations. Organizations relying on this proxy functionality for network management or remote access services face substantial risk of service interruption, potentially affecting business continuity and operational efficiency. The vulnerability also creates opportunities for attackers to use this denial of service condition as a stepping stone for further exploitation attempts, as system instability often creates additional attack vectors.
Mitigation strategies for CVE-2004-1502 should prioritize immediate patching of the 602 Lan Suite to version 2004.0.04.1000 or later, which contains the necessary fixes for the Telnet proxy loop condition. Network administrators should implement proper input validation and connection limiting mechanisms at the network perimeter, using firewalls or intrusion prevention systems to monitor and restrict Telnet proxy access. The implementation of connection rate limiting and socket timeout controls can help prevent the resource exhaustion condition from occurring, while proper monitoring systems should be deployed to detect unusual connection patterns that may indicate exploitation attempts. Additionally, organizations should consider isolating the Telnet proxy functionality from critical network services and implementing network segmentation to limit the potential impact of successful exploitation attempts. The vulnerability highlights the importance of robust error handling and resource management in network services, as outlined in the ATT&CK framework's defensive techniques for preventing resource exhaustion attacks, which emphasize the need for proper connection management and monitoring of system resource utilization.