Blockchain Security Training Network & Node Security 2

Question 1

An attacker isolates a node from the honest network and feeds it a false view of the blockchain. What attack is this?

Accepted Answer

Eclipse attack

Answer

An eclipse attack monopolizes a victim node's peer connections to control all information it receives.

Question 2

Which practice best mitigates eclipse attacks on a node?

Accepted Answer

Diversifying inbound/outbound peers and using anchor connections

Answer

Maintaining diverse peers and persistent anchor connections makes it harder to monopolize a node's connections.

Question 3

What is the primary purpose of a node running behind a firewall exposing only the necessary P2P port?

Accepted Answer

Reduce the attack surface for remote exploitation

Answer

Limiting exposed ports reduces avenues an attacker can use to reach the node.

Question 4

A full node's RPC interface is exposed to the public internet without authentication. What is the main risk?

Accepted Answer

Unauthorized commands, wallet access, or DoS

Answer

Open RPC endpoints can let attackers query data, drain wallets, or overwhelm the node.

Question 5

Which transport-layer protection helps secure communication between a node and its remote RPC clients?

Accepted Answer

TLS encryption with authentication

Answer

TLS encrypts and authenticates the channel, preventing eavesdropping and tampering.

Blockchain Practice Test