FIREWALL-BASED DEFENSE STRATEGIES AGAINST MAN-IN-THE-MIDDLE ATTACKS

Abstract

Firewalls serve as the first line of defense against Man-in-the-Middle (MITM) attacks, which compromise the confidentiality, integrity, and authenticity of digital communication. This paper presents a structured taxonomy of core MITM techniques, including ARP poisoning, DNS spoofing, HTTPS degradation (also known as SSL stripping), and session hijacking, as well as specialized variants targeting cloud services, web browsers, mobile applications, and IoT devices. Particular attention is given to vulnerabilities in VPN infrastructures, where centralized traffic decryption creates high-value targets, and to weaknesses in IoT ecosystems stemming from unvalidated certificates and outdated factory configurations. The analytical-comparative methodology integrates a literature review, statistical assessment of the economic impact of MITM incidents, and a practical demonstration of advanced firewall capabilities using Linux iptables/nftables configuration. The paper outlines both fundamental and advanced features of modern firewall solutions, including ACL rules, stateful inspection, application-layer filtering, DNS filtering, TLS inspection, and integration with IDS/IPS systems. Illustrative examples from widely used applications highlight the strengths and limitations of these measures. The findings emphasize that while firewalls are essential, they are not sufficient on their own. Effective protection requires a multilayered architecture that combines DNS encryption, strict TLS certificate validation, anomaly detection, and continuous user education to significantly reduce the risks and economic consequences of MITM attacks in contemporary digital networks.