Why can some arbitrage trades be completed within a second? This seemingly simple question actually hides the most complex game theory within the DeFi ecosystem.

The key point is **time advantage**. Completing all operations within the same block allows attackers to completely bypass the competitive window of traditional arbitrage. Typically, the arbitrage process is as follows: identify opportunity → send transaction → wait for block confirmation → be preempted by other arbitrageurs.秒级操作 directly skips this process, atomically executing all logic within a single transaction, leaving no opportunity for others to intervene.

From a technical perspective, this attack exploits the **oracle update delay** vulnerability. Let's look at the actual update cycles of various data sources: on-chain oracles (like Chainlink) take 3 to 10 seconds to update prices; data on price chart websites updates every 15 to 60 seconds; exchange APIs are slightly faster but still have a 1 to 3 second delay. A one-second attack occurs entirely within these delay windows, and external systems often cannot react quickly enough to what is happening.

The economic advantage is even more apparent. First is the **zero-risk characteristic**. Since all operations are completed within a single transaction, it either succeeds entirely or fails and reverts to the initial state. There’s no situation like "half-done and getting caught," which completely eliminates partial execution risk.

Second is the **extreme optimization of Gas costs**. On chains like BSC, traditional multi-transaction arbitrage might consume 50,000 Gas × 3 transactions = 150,000 Gas. The same attack compressed into a single transaction requires around 80,000 Gas, saving a full 47% of the cost. Even better, a single transaction also avoids additional risks caused by price changes between transactions.

How exactly is this done? Attackers usually develop a custom smart contract that encapsulates the entire attack logic. After receiving flash loan funds, it immediately performs DEX arbitrage, lending protocol risk arbitrage, or cross-protocol arbitrage chains within the contract. All calculations and transactions are completed within a few hundred milliseconds of contract execution, then the loan is repaid and the operation ends.

The emergence of this pattern essentially reflects the increased maturity of the DeFi market—markets no longer tolerate inefficiencies, and even second-level time differences can be precisely captured and exploited. It also indicates that traditional oracle designs are beginning to show their bottlenecks.