Auditing, Testing, and Monitoring in Blockchain Security BDC Practice Questions (Page 10)

Questions 46–50

1. 46application · medium

   A DeFi protocol has been deployed on mainnet. The team wants to detect a potential flash loan attack in real time. Which monitoring approach is most effective?

   • AReview the protocol's code for vulnerabilities
   • BSet up a server that periodically queries the protocol's total value locked
   • CMonitor the price of the protocol's governance token
   • DMonitor the protocol's smart contract events and set alerts for unusual transaction patterns, such as large borrows and repayments in the same block
   Reveal Solution Discussion Select an answer first
2. 47foundation · easy

   In property-based testing, what does a 'property' refer to?

   • AA general invariant that should hold for a wide range of inputs
   • BA specific test case with fixed input and expected output
   • CA configuration parameter of the testing framework
   • DA list of all possible function signatures
   Reveal Solution Discussion Select an answer first
4. 48application · medium

   An auditor is reviewing a DeFi protocol that allows users to provide liquidity to a pool. The protocol calculates the user's share based on the current pool balances. Which vulnerability is most likely present?

   • AOracle manipulation
   • BReentrancy
   • CInteger overflow
   • DFirst-depositor attack
   Reveal Solution Discussion Select an answer first
5. 49application · medium

   A security auditor is assessing a new proof-of-stake blockchain that uses a small set of validators. The auditor wants to evaluate the risk of a 51% attack. Which factor is most important to consider?

   • AThe number of validators in the network, regardless of the amount of stake they hold.
   • BThe geographic distribution of the validators' nodes.
   • CThe hash rate of the network and the difficulty of the mining algorithm.
   • DThe total amount of stake controlled by the largest validators and the economic cost to acquire enough stake to control the consensus.
   Reveal Solution Discussion Select an answer first
6. 50expert · hard

   A DeFi protocol has been exploited, and the team needs to respond. The exploit is ongoing: the attacker is draining funds from a lending pool. The team has a multi-sig wallet that can pause the protocol, but pausing will lock user funds temporarily. What is the best immediate action?

   • AWait until the exploit is fully understood before taking any action, to avoid making things worse.
   • BUpgrade the smart contract immediately to fix the vulnerability, without pausing.
   • CContact the attacker and negotiate a bounty to return the funds.
   • DPause the protocol immediately to stop the drain, then investigate the exploit and communicate with users.
   Reveal Solution Discussion Select an answer first