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In this episode of The Van Wirdum, Sjorsnado, Aaron and Sjors discuss the Erebus attacks. The episode is a sequel to last week’s episode on Eclipse Attacks, a type of attack that isolates a Bitcoin node by occupying all connection slots to prevent the node from receiving transactions. Erebus attacks are Eclipse attacks in which an attacker essentially spoofs an entire portion of the Internet.
The Internet is made up of autonomous systems, basically clusters of IP addresses owned by the same entity, such as an ISP. Last week, the hosts explained how Bitcoin Core nodes can counter Eclipse attacks by ensuring that they are connected to a variety of IP addresses from different autonomous systems. However, it turns out that some autonomous systems can effectively act as bottlenecks when trying to reach other autonomous systems.
This allows an attacker managing such a bottleneck to launch a successful Eclipse attack, even against nodes connecting to multiple autonomous systems.
Since its most recent release, Bitcoin Core includes an optional feature – ASMAP – to counter these types of Eclipse attacks. The hosts explain how mapping the internet has enabled Bitcoin Core contributors to create a tool that ensures that Bitcoin nodes not only connect to different autonomous systems, but also keep them from getting stuck to sit behind the aforementioned bottlenecks.