CVE-2002-2307 in Benhur Software Update
Summary
by MITRE
The default configuration of BenHur Firewall release 3 update 066 fix 2 allows remote attackers to access arbitrary services by connecting from source port 20.
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Analysis
by VulDB Data Team • 07/13/2024
The vulnerability described in CVE-2002-2307 represents a critical misconfiguration issue within the BenHur Firewall software version 3 update 066 fix 2. This flaw stems from the default firewall configuration that fails to properly restrict network access based on source port information, creating an unintended pathway for remote attackers to bypass security controls. The specific weakness lies in how the firewall handles connections originating from source port 20, which is traditionally associated with the FTP data port service. This default configuration allows unauthorized access to arbitrary network services, effectively undermining the fundamental purpose of firewall protection mechanisms.
The technical implementation of this vulnerability demonstrates a failure in proper access control enforcement within the firewall's packet filtering rules. When connections arrive from source port 20, the firewall's default configuration fails to apply appropriate security restrictions, enabling attackers to exploit this loophole to gain access to services that should otherwise be protected. This represents a classic case of insufficient input validation and access control enforcement, which aligns with CWE-284 access control vulnerabilities. The flaw operates at the network layer where the firewall should be enforcing strict source port-based filtering but instead permits connections that bypass normal security protocols. Attackers can leverage this weakness by crafting packets that appear to originate from port 20, thereby circumventing the firewall's intended security posture.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with a potential foothold for further network exploration and exploitation. Once an attacker successfully connects through this port 20 bypass mechanism, they can potentially access any service that is not properly protected by additional security measures. This creates a significant risk for organizations that rely on the BenHur Firewall for network segmentation and protection, as the default configuration essentially provides a backdoor that undermines the entire security architecture. The vulnerability particularly affects environments where the firewall is used to protect sensitive internal services, as attackers can exploit this weakness to reach systems that should be isolated from external access. This misconfiguration also violates fundamental principles of network security and aligns with ATT&CK technique T1046 network service scanning, as it allows for reconnaissance activities that would normally be blocked by proper firewall rules.
Organizations should immediately implement mitigation strategies that involve modifying the firewall's default configuration to properly enforce access controls based on source port information. The recommended approach includes configuring the firewall to reject connections from source port 20 that attempt to access services not explicitly authorized for such connections. This requires implementing more granular access control lists that properly distinguish between legitimate FTP data connections and malicious attempts to exploit the vulnerability. Additionally, network administrators should conduct comprehensive security audits to identify any other potential misconfigurations that could create similar access bypass opportunities. The fix should involve updating the firewall rules to ensure that source port 20 connections are properly filtered based on destination services and network zones, effectively closing this unintended access path while maintaining legitimate network functionality. This remediation process should follow established security frameworks and principles that emphasize least privilege access and proper network segmentation to prevent similar vulnerabilities from occurring in the future.