CVE-2024-43391 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_PORTFORWARDING.SRC_IP environment variable which can lead to a DoS.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 08/22/2025
This vulnerability represents a critical configuration manipulation flaw within firewall services that allows low-privileged remote attackers to execute unauthorized changes to core network security policies. The vulnerability specifically targets the FW_PORTFORWARDING.SRC_IP environment variable, which serves as an entry point for attackers to modify essential firewall parameters including packet filtering rules, packet forwarding configurations, network access control policies, and network address translation settings. The exploitation of this vulnerability demonstrates a significant privilege escalation issue where unauthenticated or minimally authenticated users can gain the ability to alter fundamental network security controls that should typically require administrative privileges.
The technical implementation of this vulnerability stems from inadequate input validation and insufficient access control mechanisms within the firewall service configuration interface. When the FW_PORTFORWARDING.SRC_IP environment variable is manipulated, it creates a path for arbitrary configuration modifications that bypass normal security boundaries and authentication checks. This flaw aligns with CWE-264, which addresses permissions, privileges, and access controls, and represents a classic case of insufficient input sanitization that allows attackers to inject malicious configuration parameters into the system. The vulnerability's impact is particularly severe because it operates at the network infrastructure level, where changes to packet filtering, forwarding, and NAT configurations can immediately disrupt network connectivity and security posture.
The operational consequences of this vulnerability extend far beyond simple service disruption, as it enables attackers to create persistent network access points while simultaneously compromising the integrity of the firewall's security policies. A successful attack can result in complete network isolation of affected systems, unauthorized data exfiltration through modified forwarding rules, or the establishment of backdoor access paths that persist across system reboots. The DoS potential emerges not only from direct service disruption but also from the cascading effects of misconfigured network policies that can bring down entire network segments or prevent legitimate traffic from reaching its intended destinations. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1071.004 for application layer protocol and T1499.004 for network disruption, highlighting how attackers can leverage configuration manipulation to achieve broader operational goals.
Organizations affected by this vulnerability should immediately implement network segmentation strategies to isolate firewall services from untrusted networks and deploy comprehensive monitoring solutions that can detect anomalous configuration changes. The recommended mitigations include implementing strict input validation for all environment variables, enforcing principle of least privilege access controls, and deploying automated configuration management systems that can detect and revert unauthorized modifications. Security teams should also establish baseline configuration snapshots and implement change management procedures that require explicit approval for any modifications to critical firewall parameters. Additionally, organizations should consider implementing network intrusion detection systems specifically tuned to monitor for suspicious environment variable modifications and configuration change patterns that align with the attack vectors described in this vulnerability.