MEV Sandwich Attack: Systemic Risk in the Blockchain Ecosystem

With the continuous maturation of blockchain technology and the increasingly complex ecosystem, Maximum Extractable Value (MEV) has evolved from being initially seen as an incidental vulnerability caused by transaction ordering flaws to a highly complex, systemic profit harvesting mechanism. Among these, sandwich attacks have drawn significant attention due to their unique operational methods, becoming one of the most controversial and destructive attack techniques in the DeFi ecosystem.

1. Basic Concepts of MEV and Sandwich Attack

The Source and Technological Evolution of MEV

MEV originally refers to the additional economic benefits obtained by miners or validators during the block construction process through manipulating the order of transactions and having the right to include or exclude transactions. With the development of tools like flash loans and transaction bundling, previously sporadic arbitrage opportunities have gradually been amplified, forming a complete profit harvesting chain. MEV has evolved from an occasional event into a systematic and industrialized arbitrage model, existing not only on Ethereum but also showing different characteristics on other public chains.

The principle of sandwich attacks

Sandwich attacks are a typical operational means in MEV extraction. Attackers monitor the memory pool transactions in real-time, submitting transactions before and after the target transaction, forming a "front-running-target transaction-back-running" transaction sequence, and achieving arbitrage through price manipulation. The core steps include:

1. Front-running: When an attacker detects a large or high slippage trade, they immediately submit a buy order to push up or suppress the market price.
2. Target Trading Squeeze: The target trade is executed after the price has been manipulated, resulting in additional costs for the trader.
3. Post-trade: The attacker submits a reverse trade to sell previously acquired assets at a high price or buy at a low price, locking in the price difference profit.

2. The Evolution and Current Status of MEV Sandwich Attacks

From sporadic vulnerabilities to systemic mechanisms

MEV attacks have evolved from initially sporadic small-scale incidents to a systematic and industrialized arbitrage model today. Attackers utilize high-speed networks and sophisticated algorithms to construct highly automated arbitrage systems. Currently, there have been cases of single transactions yielding profits of hundreds of thousands or even millions of dollars, marking the MEV mechanism as a mature profit harvesting system.

Attack characteristics of different platforms

• Ethereum: The public and transparent memory pool makes it easy to monitor pending transactions, and attackers can pay high Gas fees to take precedence in the transaction packaging order.
• Solana: Although there is no traditional memory pool, the centralization of validator nodes may allow attackers to obtain transaction data, leading to frequent attacks and large profits.
• Binance Smart Chain: Lower transaction costs and simplified structure provide space for arbitrage activities, with various types of bots employing similar strategies to achieve profit extraction.

Latest Case

On March 13, 2025, a transaction of approximately 5 SOL on a certain trading platform suffered a sandwich attack, resulting in a loss of $732,000 for the trader. The attacker exploited front-running to seize Block packaging rights, inserting transactions before and after the target transaction, causing the actual execution price to deviate significantly from expectations.

In the Solana ecosystem, sandwich attacks are presenting new patterns. Some validators are suspected of colluding with attackers, leaking transaction data to carry out precise strikes. Certain attackers have seen their short-term profits grow from tens of millions of dollars to over a hundred million dollars.

3. The Operational Mechanism and Technical Challenges of Sandwich Attacks

To implement a sandwich attack, the following conditions must be met:

1. Transaction monitoring and capturing: Real-time monitoring of unconfirmed transactions in the memory pool, identifying transactions with significant price impact.
2. Priority gas fee competition: Use high gas fees or priority fees to ensure your transaction is executed before or after the target transaction.
3. Accurate Calculation and Slippage Control: Accurately calculate the trading volume and expected slippage, while driving price fluctuations and ensuring that the target trade does not fail due to exceeding the slippage settings.

This type of attack not only requires high-performance trading bots and fast network response, but also incurs high miner fees. When multiple bots compete for the same target transaction simultaneously, it further squeezes profit margins.

4. Industry Responses and Prevention Strategies

General User Prevention Strategies

1. Set reasonable slippage protection: Set a reasonable slippage tolerance based on market volatility and expected liquidity conditions.
2. Use privacy trading tools: Leverage technologies such as private RPC and order packing auctions to conceal transaction data and reduce the risk of attacks.

Ecosystem Technology Improvement Suggestions

1. Transaction Ordering and Proposer-Builder Separation (PBS): Limiting the control of a single node over transaction ordering.
2. MEV-Boost and Transparency Mechanism: Introduce third-party relay services to enhance the transparency of the block construction process.
3. Off-chain order auction and outsourcing mechanism: Achieve batch matching of orders to enhance the likelihood of users obtaining the best price.
4. Smart Contracts and Algorithm Upgrades: Utilize artificial intelligence and machine learning technologies to enhance the monitoring and prediction capabilities of abnormal fluctuations in on-chain data.

V. Conclusion

MEV sandwich attacks have evolved from sporadic vulnerabilities into a systematic profit extraction mechanism, posing a severe challenge to the DeFi ecosystem and the security of user assets. Recent cases indicate that the risk of attacks on mainstream platforms continues to escalate. To protect user assets and market fairness, the blockchain ecosystem must work together in technological innovation, optimization of trading mechanisms, and regulatory collaboration to find a balance between innovation and risk, achieving sustainable development.