CVE-2024-43392 in FL MGUARD 2102
Summary
by MITRE • 09/10/2024
A low privileged remote attacker can perform configuration changes of the firewall services, including packet filter, packet forwarding, network access control or NAT through the FW_INCOMING.FROM_IP FW_INCOMING.IN_IP FW_OUTGOING.FROM_IP FW_OUTGOING.IN_IP environment variable which can lead to a DoS.
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Analysis
by VulDB Data Team • 08/22/2025
This vulnerability represents a critical configuration manipulation issue within firewall services that allows low-privileged remote attackers to execute unauthorized changes to core network security policies. The flaw specifically targets environment variables including FW_INCOMING.FROM_IP, FW_INCOMING.IN_IP, FW_OUTGOING.FROM_IP, and FW_OUTGOING.IN_IP which are typically used to define packet filtering and routing parameters. These variables control fundamental aspects of network traffic management including packet filtering rules, packet forwarding behavior, network access control policies, and network address translation configurations. The vulnerability arises from insufficient input validation and access control mechanisms that permit unauthorized modification of these critical parameters from remote locations.
The technical implementation of this vulnerability stems from improper environment variable handling within the firewall service configuration system. When these variables are processed without adequate sanitization or authentication checks, attackers can inject malicious values that alter the firewall's operational behavior. This misconfiguration allows an attacker to manipulate routing decisions, modify access control lists, and potentially disable critical network security functions. The vulnerability is particularly concerning because it operates at the configuration level rather than requiring exploitation of a specific software flaw, making it more persistent and difficult to detect. The attack vector involves remote access to the system where the attacker can modify these environment variables through legitimate configuration interfaces or by exploiting existing access points.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete network security compromise and potential denial of service conditions. An attacker who successfully manipulates these environment variables can redirect network traffic, block legitimate access to critical systems, or disable essential network services entirely. The configuration changes can lead to complete network isolation of targeted systems or create unexpected traffic paths that bypass security controls. The DoS potential is significant as the attacker can disable core firewall functionality, rendering network security ineffective and potentially causing cascading failures throughout the network infrastructure. This vulnerability effectively undermines the fundamental security posture of the affected systems by allowing unauthorized modification of network access controls.
Mitigation strategies should focus on implementing strict access controls and input validation for all environment variables used in firewall configuration. The system should enforce mandatory access controls that prevent modification of critical configuration parameters by unauthorized users or processes. Environment variable validation should include comprehensive sanitization to prevent injection attacks and ensure that only legitimate values are accepted. Network segmentation and least privilege principles should be enforced to limit access to configuration interfaces. The implementation should follow security best practices including principle of least privilege, input validation, and proper authentication mechanisms. Organizations should also implement monitoring and logging of configuration changes to detect unauthorized modifications and maintain audit trails of all firewall policy adjustments. This vulnerability aligns with CWE-20 (Improper Input Validation) and CWE-79 (Cross-site Scripting) categories while mapping to ATT&CK techniques including T1059 (Command and Scripting Interpreter) and T1566 (Phishing) for initial access and T1499 (Endpoint Denial of Service) for the DoS impact.