Gateway compromise is the unauthorized control of a network edge device such as a router, Wi-Fi gateway, captive portal, or DNS resolver. Because these devices sit between users and the internet, an attacker who controls them can shape traffic, change name-resolution results, block access, or redirect devices to a different destination. In practice, that can silently send a login page to an attacker-controlled site, expose internal traffic, or force users onto less secure paths.
This matters in cyber security because the gateway often decides what is trusted before endpoint security can help. Real attacks may use DNS poisoning, malicious configuration changes, or abuse of remote administration to steer cloud sign-ins, intercept sessions, or collect credentials without malware on the victim device. Defenses include strong admin passwords, multi-factor protection for device management, firmware updates, segmentation, DNSSEC validation where possible, and monitoring for unexpected DNS or routing changes. In short, gateway compromise turns the network edge into an attack platform.