CVE-2000-1182 in Firebox II
Summary
by MITRE
WatchGuard Firebox II allows remote attackers to cause a denial of service by flooding the Firebox with a large number of FTP or SMTP requests, which disables proxy handling.
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Analysis
by VulDB Data Team • 04/07/2019
The vulnerability identified as CVE-2000-1182 affects WatchGuard Firebox II network security appliances, representing a classic resource exhaustion attack vector that exploits the device's proxy handling capabilities. This weakness stems from insufficient input validation and rate limiting mechanisms within the firewall's proxy services, specifically targeting the ftp and smtp protocols. The vulnerability operates by exploiting the device's failure to properly manage concurrent connection requests, allowing an attacker to overwhelm the system with a high volume of legitimate-looking protocol requests that consume available processing resources and memory.
From a technical perspective, the flaw manifests as a lack of proper traffic throttling and connection rate limiting within the Firebox II's proxy implementation. When subjected to a flood of FTP or SMTP requests, the device's proxy handling components become overwhelmed and eventually cease to process new connection requests properly. This occurs because the system does not implement adequate mechanisms to distinguish between legitimate traffic patterns and malicious flooding attempts. The vulnerability directly maps to CWE-400, which classifies unchecked resource consumption as a significant weakness in software design. The attack leverages fundamental protocol behaviors that the firewall is designed to handle, but fails to manage effectively under stress conditions.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise network security posture and availability. When the Firebox II becomes unresponsive due to proxy handling exhaustion, legitimate network traffic may be blocked or delayed, creating a denial of service condition that affects authorized users and systems. Network administrators may experience difficulty in maintaining connectivity and access to network resources, while the device itself becomes unable to perform its core security functions of filtering and monitoring traffic. This vulnerability particularly affects organizations that rely on Firebox II appliances for their network security infrastructure, as it can be exploited by attackers to disrupt critical network operations and potentially gain unauthorized access to network resources through service disruption.
Mitigation strategies for this vulnerability should focus on implementing comprehensive traffic management and rate limiting controls within the firewall configuration. Network administrators should configure connection limits and maximum concurrent session thresholds for both ftp and smtp proxy services to prevent resource exhaustion attacks. Additionally, implementing proper logging and monitoring capabilities can help detect abnormal traffic patterns that may indicate an ongoing attack. The solution aligns with ATT&CK technique T1498, which describes resource exhaustion attacks as a method for causing denial of service conditions. Organizations should also consider implementing network segmentation and access controls to limit the impact of such attacks. Regular firmware updates and security patches from WatchGuard are essential to address the underlying implementation flaws that enable this vulnerability, while network administrators should establish baseline traffic patterns to quickly identify when their systems are being targeted by similar flooding attacks.