CVE-1999-1047 in Gauntlet
Summary
by MITRE
When BSDI patches for Gauntlet 5.0 BSDI are installed in a particular order, Gauntlet allows remote attackers to bypass firewall access restrictions, and does not log the activities.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability described in CVE-1999-1047 represents a critical security flaw in the Gauntlet firewall software developed by BSDI, specifically affecting version 5.0. This issue demonstrates how improper patch management and configuration can lead to severe security implications in network defense systems. The vulnerability exploits a specific sequence of patch installations that creates an unexpected behavior in the firewall's access control mechanisms, allowing unauthorized remote access to protected network resources.
The technical root cause of this vulnerability lies in the patch application order dependency within the Gauntlet firewall implementation. When BSDI patches are applied in the particular sequence mentioned, the firewall's internal state management becomes inconsistent, creating a condition where access restrictions are bypassed without proper authentication or authorization checks. This flaw operates at the application layer of network security, specifically targeting the firewall's packet filtering and access control functions. The vulnerability essentially creates a backdoor in the firewall's normal operation, where legitimate access control mechanisms are circumvented, allowing remote attackers to traverse the firewall without proper credentials or logging of their activities.
The operational impact of this vulnerability is severe as it completely undermines the fundamental purpose of a firewall, which is to enforce access control policies and maintain security logging for audit purposes. Remote attackers who can exploit this vulnerability gain unrestricted access to network resources that should be protected by the firewall, potentially leading to data breaches, system compromise, and unauthorized access to sensitive information. The lack of logging functionality compounds the security risk, as network administrators cannot detect or trace unauthorized access attempts, making it extremely difficult to identify security incidents or perform forensic analysis following a breach. This vulnerability directly violates security principles outlined in the CIA triad, specifically compromising both confidentiality and integrity of network resources.
The mitigation strategies for this vulnerability require immediate patch application in the correct order as specified by BSDI, along with comprehensive network monitoring and access control reviews. Organizations should implement proper patch management procedures to prevent similar issues in the future, including thorough testing of patch sequences before deployment in production environments. Security teams must also establish robust logging mechanisms and monitoring systems to detect anomalous network behavior, ensuring that any unauthorized access attempts are properly recorded and investigated. This vulnerability highlights the importance of following vendor-recommended patch installation procedures and demonstrates how seemingly minor configuration issues can result in catastrophic security failures. The issue also emphasizes the need for regular security assessments and vulnerability scanning to identify potential misconfigurations that could be exploited by threat actors, aligning with best practices outlined in the MITRE ATT&CK framework for network security operations and the CWE catalog for software security weaknesses.