Mallet in the Middle

This guide explains how to place a small GL.iNet router running OpenWRT between a kiosk and its upstream network to perform transparent man-in-the-middle interception. It covers Wi-Fi management setup, bridging the Ethernet ports, disabling the firewall, installing tcpdump and necessary kernel modules, and crafting ebtables/iptables rules to impersonate the victim and router at both MAC and IP layers. The post then shows how to redirect TCP flows to redsocks and tunnel them via SSH to Mallet for inspection and manipulation, enabling end-to-end interception and analysis of kiosk traffic while keeping the device largely invisible on the wire.