DeFi Security and Audits Flashcards
7 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 DeFi Security and Audits flashcards as text
What is the main advantage of formal verification in a smart contract audit?
Answer: It mathematically proves the code satisfies specified properties
Formal verification uses mathematical methods to prove that code meets its specification under all inputs, catching flaws testing might miss.
What does a 'fuzzing' tool do during a security review?
Answer: Feeds random or generated inputs to find unexpected reverts or invariant violations
Fuzzers bombard functions with varied inputs to surface edge-case failures and broken invariants that manual review can overlook.
Why is a reentrancy guard (mutex) used in withdrawal functions?
Answer: It prevents a function from being re-entered before its first execution completes
A reentrancy guard locks the function so a malicious external call cannot recursively re-invoke it and drain funds.
What is a signature replay attack in DeFi?
Answer: A valid signed message is reused to repeat an authorized action
Without a nonce or domain separator, an attacker can resubmit a previously valid signature to trigger the same action again.
How does EIP-712 with nonces help prevent signature replay?
Answer: It binds signatures to a unique nonce and domain so each can be used only once
Including a per-user nonce and chain/contract domain in the signed data ensures a signature is valid only once and only on the intended contract.
What is a key risk when a DeFi protocol composes with an external unaudited protocol?
Answer: Composability risk, where a flaw or exploit in the dependency cascades into your protocol
DeFi's money-lego composability means a vulnerability or failure in an integrated protocol can directly compromise contracts that rely on it.
Why should auditors review how a protocol handles a sudden depeg of a stablecoin collateral?
Answer: A depeg can leave loans undercollateralized and trigger cascading bad debt
If a stablecoin used as collateral loses its peg, positions can become undercollateralized faster than liquidations can clear them, creating systemic bad debt.