Definition
BGP hijacking is a type of internet routing attack where an attacker falsely announces ownership of IP address blocks that do not belong to them. This reroutes traffic intended for legitimate destinations through the attacker's controlled network, allowing them to intercept, modify, or block data. The Border Gateway Protocol (BGP), which governs how internet traffic is routed between networks, is the underlying mechanism exploited in these attacks. Attackers achieve this by submitting falsified routing information to internet service providers, causing global routing tables to update with the incorrect paths. This can lead to significant service disruptions, data theft, and reputational damage for affected organizations. A notable example occurred in 2019 when a Ukrainian ISP inadvertently announced routes for Google's IP space, causing widespread YouTube outages. Unlike a denial of service attack which aims to overwhelm a target, BGP hijacking focuses on redirecting traffic for malicious purposes. This concept is frequently assessed in cybersecurity certifications like CompTIA Security+, CySA+, and CISSP, highlighting its importance in network security.