CVE-2008-0534 in Iconfidant SSH
Summary
by MITRE
The SSH server in (1) Cisco Service Control Engine (SCE) before 3.1.6, and (2) Icon Labs Iconfidant SSH before 2.3.8, allows remote attackers to cause a denial of service (device restart or daemon outage) via a high rate of login attempts, aka Bug ID CSCsi68582.
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Analysis
by VulDB Data Team • 11/28/2024
The vulnerability described in CVE-2008-0534 represents a significant denial of service weakness affecting SSH server implementations in specific network infrastructure devices. This flaw manifests in two distinct product lines: Cisco Service Control Engine (SCE) versions prior to 3.1.6 and Icon Labs Iconfidant SSH software before version 2.3.8. Both platforms suffer from identical operational weaknesses that can be exploited by remote attackers to disrupt service availability. The vulnerability specifically targets the authentication mechanisms of these SSH servers, creating a scenario where legitimate service operations become impossible due to system resource exhaustion.
The technical implementation of this vulnerability stems from inadequate rate limiting and connection handling within the SSH server components of these affected systems. When attackers submit a high volume of login attempts in rapid succession, the affected SSH daemons fail to properly manage these connections, leading to resource exhaustion that ultimately results in system restarts or daemon outages. This behavior indicates a fundamental flaw in how these systems process authentication requests without sufficient protection against brute force or denial of service attacks. The vulnerability operates at the protocol level, leveraging the inherent design of SSH authentication to create a cascading failure condition that affects system availability rather than data confidentiality or integrity.
From an operational perspective, this vulnerability presents a critical risk to network infrastructure availability and reliability. Organizations relying on affected Cisco SCE appliances or Icon Labs Iconfidant SSH implementations face potential service disruptions that could impact business continuity and network operations. The remote nature of the attack means that adversaries do not require physical access or network proximity to exploit the vulnerability, making it particularly dangerous for systems exposed to internet traffic. The impact extends beyond simple service interruption, as device restarts can result in loss of configuration data, temporary network outages, and potential data loss during recovery operations. This type of vulnerability directly impacts the availability aspect of the CIA triad and can be classified as a privilege escalation vector that allows attackers to gain control over system resources through deliberate resource exhaustion.
The exploitation of this vulnerability aligns with several ATT&CK framework techniques including privilege escalation and denial of service, specifically targeting the T1499.004 sub-technique for network denial of service and T1078 for valid accounts. The vulnerability's classification under CWE-400 indicates a weakness in resource management where the system fails to properly handle resource consumption under stress conditions. Organizations should implement immediate mitigations including rate limiting configurations, connection throttling, and firewall rules to restrict SSH access from suspicious sources. Network segmentation and monitoring solutions should be deployed to detect unusual login patterns that may indicate exploitation attempts. Regular patching and system updates remain essential to address the underlying implementation flaws that enable this attack vector. The vulnerability demonstrates the importance of robust resource management in network infrastructure components and highlights the need for proper security controls in critical system services that handle authentication requests.