CVE-2004-1918 in RSniff
Summary
by MITRE
RSniff 1.0 allows remote attackers to cause a denial of service (connection exhaustion) via a large number of connections with a command other than AUTHENTICATE, or without any data, which prevents the socket from being closed properly.
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Analysis
by VulDB Data Team • 06/18/2018
The vulnerability described in CVE-2004-1918 affects RSniff version 1.0, a network monitoring tool designed to capture and analyze network traffic. This particular flaw represents a classic denial of service condition that can be exploited by remote attackers to disrupt the normal operation of the system. The vulnerability specifically targets the connection handling mechanisms within RSniff, creating a scenario where legitimate network operations become impossible due to resource exhaustion.
The technical flaw manifests when RSniff receives a large volume of network connections that do not follow the expected authentication protocol. When connections are established without proper authentication or with commands other than AUTHENTICATE, the software fails to properly close the associated socket connections. This improper connection management creates a resource leak condition where the system accumulates open connections that consume memory and file descriptor resources. The vulnerability is particularly dangerous because it can be triggered remotely without requiring any authentication or privileged access, making it accessible to any attacker with network connectivity to the affected system.
The operational impact of this vulnerability extends beyond simple service disruption. When the system experiences connection exhaustion, it becomes unable to accept new legitimate connections, effectively rendering the network monitoring capabilities useless. Network administrators may find that the system becomes unresponsive to legitimate network traffic analysis requests while simultaneously being overwhelmed by the accumulation of improperly closed connections. This condition can persist until the system is manually restarted or until the accumulated connections naturally time out, potentially lasting for extended periods depending on the system configuration and resource availability.
From a cybersecurity perspective, this vulnerability aligns with CWE-400, which addresses unchecked resource consumption, and represents a form of resource exhaustion attack that can be classified under the ATT&CK technique T1499.004 for network denial of service. The flaw demonstrates poor input validation and resource management practices within the application, where the software fails to properly handle abnormal connection patterns. Organizations using RSniff 1.0 should implement immediate mitigations including connection rate limiting, implementing proper connection timeout mechanisms, and ensuring that all incoming connections are properly authenticated before resource allocation occurs. Network segmentation and firewall rules can also help limit the attack surface by restricting direct access to the RSniff service, while monitoring systems should be configured to detect unusual connection patterns that may indicate exploitation attempts.
The vulnerability highlights the importance of proper resource management in network monitoring tools and underscores the need for robust connection handling routines. Attackers can exploit this weakness by simply establishing multiple connections with malformed or unauthorized commands, consuming system resources without requiring any specialized tools or deep technical knowledge. This makes the vulnerability particularly dangerous as it can be easily exploited by automated tools or casual attackers. System administrators should also consider implementing connection pooling mechanisms and proper connection lifecycle management to prevent similar issues in other network applications. Regular security audits and penetration testing should include examination of connection handling routines to identify similar resource management flaws that could be exploited in a variety of network applications.