BGP hijacking, also known as prefix hijacking, route hijacking, or IP hijacking, is the illegitimate takeover of groups of IP addresses by corrupting Internet routing tables. The Border Gateway Protocol (BGP) is the protocol that manages how packets are routed across the internet through the exchange of routing and reachability information among edge routers. BGP hijacking occurs when an Autonomous System (AS) announces that it owns an IP address block that it does not actually own, control, or route to. This can lead to internet traffic being misrouted, which can cause various issues such as traffic interception, black holing, or traffic analysis.
Mechanisms of BGP Hijacking
BGP hijacking can occur in several ways:
- An AS falsely claims it originates a prefix that it does not actually originate.
- An AS announces a more specific prefix than the true originating AS.
- An AS announces it can route traffic to the hijacked AS through a shorter route than is already available, regardless of whether the route exists.
Consequences of BGP Hijacking
The consequences of BGP hijacking can be severe, including:
- Internet traffic being routed incorrectly, potentially around the world unnecessarily, which can increase latency.
- Traffic being monitored or intercepted, which poses security risks.
- Traffic being directed to fake websites, which can lead to phishing attacks or other forms of fraud.
- Disruption of internet services, as legitimate traffic is misrouted.
Examples of BGP Hijacking
There have been several public incidents of BGP hijacking, including attacks on financial services and government networks. For instance, hackers have used BGP hijacking to steal cryptocurrency by rerouting traffic to servers they controlled. Another example is the incident involving Vodafone Idea, where traffic was inundated 13 times higher than average, leaving users unable to access the internet.
Prevention and Detection
To protect against BGP hijacking, organizations can implement measures such as:
- Mutually Agreed Norms for Routing Security (MANRS), which includes best practices like filtering and making correct routing announcements.
- Resource Public Key Infrastructure (RPKI), which authenticates route origins via cryptographic certificate chains.
- Monitoring network latency and BGP routes taken by network traffic to detect any abnormal route changes.
Despite the availability of security extensions for BGP and third-party route databases for validating routes, the default design of BGP is to trust all route announcements sent by peers, which makes it vulnerable to hijacking. Few ISPs rigorously enforce checks on BGP sessions, which contributes to the problem.
BGP hijacking remains a potent tool for malicious actors, including nation-state hackers, and continues to be a significant threat to the security and stability of the internet.