Sandwich Attacks
A sandwich attack places two transactions around yours: one before (frontrun) that moves the price up, and one after (backrun) that sells at the inflated price. You get a worse price; the bot profits from the difference.
Anatomy of a Sandwich
1
Frontrun
Bot buys ETH, pushing price up
->
2
Your Swap
You buy ETH at a worse price
->
3
Backrun
Bot sells ETH at the inflated price
->
4
Profit
Bot keeps the price difference
Your Loss Calculator
Price Impact (no attack)
0.50%
Your Extra Loss
$125
Bot Profit
~$120
Protection Methods
- Flashbots Protect - Send txs through private mempools
- Low slippage - Reduce max slippage tolerance
- MEV-blocker - OFA (Order Flow Auctions) that rebate MEV to you
- Smaller swaps - Split large trades across multiple txs
- CoW Swap - Batch auctions with MEV protection built in