A blockchain network is designed to be permissionless and uses PoW. The team is concerned about eclipse attacks. Which mitigation is most effective given the permissionless nature?

Disable peer discovery entirely.

Limit the number of peers to a small fixed set.

Use a diverse set of peer discovery mechanisms and maintain a large number of outbound connections.

Require identity certificates for all nodes.

A company runs a blockchain node that participates in consensus. The node's operating system is outdated and missing critical security patches. The team wants to minimize the risk of exploitation while maintaining node availability. What is the best course of action?

Continue running the node without patching to avoid downtime.

Apply the patches without restarting the node, assuming they take effect immediately.

Schedule a maintenance window to apply the latest security patches and restart the node, ensuring the node is up-to-date.

Disable the node's network connectivity until the patches are applied.

A blockchain network is facing a Sybil attack where an attacker creates many fake nodes to surround honest nodes. The team is considering countermeasures. Which approach is most effective in a permissioned blockchain?

Require nodes to present a valid identity certificate issued by a trusted authority.

Randomly select peers from a public list of all nodes.

Use a proof-of-work puzzle for node admission.

Increase the number of connections each node maintains.

EC-CouncilBlockchain Developer Certification

Domain 7Objective 2

Network Layer, Consensus, Smart Contract, and Node Security Best Practices BDC Practice Questions (Page 9)

Part of the Blockchain Security and DeFi Development domain, which makes up ~11% of our current practice bank.

45questions here

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Questions 41–45

41expert · hard
A blockchain network is designed to be permissionless and uses PoW. The team is concerned about eclipse attacks. Which mitigation is most effective given the permissionless nature?
Select an answer first
42application · medium
A smart contract allows users to set a 'referrer' address. The contract does not validate that the referrer is a legitimate user. What is the most likely security issue?
Select an answer first
43application · medium
A company runs a blockchain node that participates in consensus. The node's operating system is outdated and missing critical security patches. The team wants to minimize the risk of exploitation while maintaining node availability. What is the best course of action?
Select an answer first
44expert · hard
A blockchain network is facing a Sybil attack where an attacker creates many fake nodes to surround honest nodes. The team is considering countermeasures. Which approach is most effective in a permissioned blockchain?
Select an answer first
45application · medium
A proof-of-stake blockchain is considering a change to reduce the risk of 'nothing at stake' attacks. Which mechanism is specifically designed to penalize validators who vote on conflicting blocks?
Select an answer first

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Network Layer, Consensus, Smart Contract, and Node Security Best Practices BDC Practice Questions (Page 9)

Questions 41–45

A blockchain network is designed to be permissionless and uses PoW. The team is concerned about eclipse attacks. Which mitigation is most effective given the permissionless nature?

A smart contract allows users to set a 'referrer' address. The contract does not validate that the referrer is a legitimate user. What is the most likely security issue?

A company runs a blockchain node that participates in consensus. The node's operating system is outdated and missing critical security patches. The team wants to minimize the risk of exploitation while maintaining node availability. What is the best course of action?

A blockchain network is facing a Sybil attack where an attacker creates many fake nodes to surround honest nodes. The team is considering countermeasures. Which approach is most effective in a permissioned blockchain?

A proof-of-stake blockchain is considering a change to reduce the risk of 'nothing at stake' attacks. Which mechanism is specifically designed to penalize validators who vote on conflicting blocks?

Keep studying — Blockchain Security and DeFi Development