Routing Attack

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Update shuda Jul 9, 2026

What Is a Routing Attack?

A routing attack is an attack carried out at the internet infrastructure level to affect the uptime or participation of a web-enabled system, such as a blockchain.

Instead of targeting the protocol directly, the attacker manipulates how data travels across the internet, intercepting or delaying the traffic exchanged between nodes.

Because most network communication relies on a small number of internet service providers (ISPs), a malicious or compromised provider can potentially influence large portions of a network.

How Routing Attacks Work

Blockchains operate as peer-to-peer networks, where nodes constantly relay transactions and blocks to one another. Routing attacks typically exploit the Border Gateway Protocol (BGP), the system that directs how traffic is routed between networks.

By advertising false routes, an attacker can reroute a network’s traffic through infrastructure they control. This technique is often called BGP hijacking.

Researchers generally describe two main categories of routing attack:

Partitioning attacks: the attacker splits a network into separate groups that can no longer communicate with each other. Once a network is partitioned, each side may continue building its own version of the ledger in isolation.
Delay attacks: the attacker intercepts traffic and slows the delivery of blocks or transactions without fully cutting communication. This can leave affected nodes working with outdated information.

Studies of Bitcoin have shown that a meaningful share of its traffic has historically passed through a limited number of providers, which is part of what makes routing attacks a recognized area of concern.

Routing Attacks and Blockchain Security

When a network is partitioned or delayed, several risks may emerge. Isolated nodes can be tricked into accepting an alternative chain, which could open the door to double-spending. A partition can also concentrate mining power on one side of the split, making a 51% attack more feasible within that segment. Delay attacks may waste computational resources and reduce the efficiency of the network.

Potential mitigations that have been proposed include increasing the diversity of network connections between nodes, monitoring for sudden changes in latency or routing behavior, and encrypting node-to-node communication so intercepted traffic is harder to exploit.

While routing attacks can be difficult to execute at scale, they remain an important consideration when assessing the overall security of a decentralized network.