Discussing The Fake Peer Attack On Bitcoin

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Bitcoin was under attack! It’s the story the mainstream media won’t tell you!

Hosts Aaron van Wirdum and Sjors Provoost finally met in Utrecht again to record “Bitcoin, Explained.” In this episode, they discussed a recent attack on the Bitcoin network, where some nodes were flooding peers with fake IP addresses.

“These random people that were connecting to them would send 500 messages, and each of those 500 messages would contain 10 addresses, that were supposed to represent other nodes on the network,” Provoost said. “The messages were real, but the content was nonsense. So, a node would connect to you, and they would send you a bunch of addresses, but it turns out those addresses were just a bunch of random numbers.”

As previously discussed in episode 13, Bitcoin nodes are connect to peers on the network through IP addresses, which they learn from their existing peers. Nodes on the network essentially share the IP addresses of other nodes.

Recently, however, some Bitcoin nodes shared large amounts of IP addresses that weren’t associated with real Bitcoin nodes at all. While this attack did not do very much damage, it did waste resources from nodes on the network. On top of that, van Wirdum and Provoost explained, the attack could offer the attacker insight into Bitcoin’s network topology by analyzing how the fake IP addresses spread through the network.

Finally, van Wirdum and Provoost discussed how the attack was solved by rate limiting the amount of shared IP addresses that any node will allow its peers to receive. Further, they considered how in free and open-source software development, fixing problems is not always as straightforward as it may seem.