A Crypto Trader Lost More Than $215,000 in a Sandwich Attack While Swapping Stablecoins

The incident happened on Uniswap v3's USDC-USDT liquidity pool, once again exposing how Maximum Extractable Value (MEV) bots take advantage of

A crypto trader fell victim to a sandwich attack on March 12 while swapping stablecoins on Uniswap v3, sti米晴coins. The incident, which occurred on Uniswap v3’s USDC-USDT liquidity pool, showcases how Maximum Extractable Value (MEV) bots exploit traders in decentralized finance (DeFi).

The trader intended to exchange $220,764 in USD Coin (USDC) for Tether (USDT). However, a bot intervened within eight seconds, disrupting the trade and leaving the trader with a mere $5,271 in USDT.

The trader planned to swap 220,764 USDC for USDT on Uniswap v3. An MEV bot intervened and pulled all the USDC liquidity from the pool before the trader’s trade could go through. Afterwards, the bot put the liquidity back into the pool.

As the bot had no liquidity to pay for the trader’s trade, it had to accept a bad price to complete the swap, leaving the trader with a small amount of USDT.

According to Michael Nadeau, founder of The DeFi Report, the attacker paid Ethereum block builder “bob-the-builder.eth” a $200,000 tip from the total amount while keeping $8,000 as profit.

DeFi researcher “DeFiac” noted that the same trader, using different wallets, might have been hit by six similar sandwich attacks within a single day. Two other wallets, “0xDDe…42a6D” and “0x999…1D215,” were also targeted, with one losing $138,838 and the other $128,003.

Some theorize that these unusual swaps might be an attempt at money laundering. DefiLlama developer 0xngmi suggested that these trades could be intentionally bad, used to clean illicit funds by routing transactions privately to an MEV bot.

Initially, some blamed Uniswap for the incident. However, CEO Hayden Adams clarified that these transactions didn’t occur through Uniswap’s official interface, which has MEV protection and slippage settings to help prevent such attacks.

This isn’t the first time we’ve seen traders targeted and nearly wiped out by sandwich attacks. Earlier this year, a trader put in 732,000 to be used for a swap but ended up with only 19,000 due to a similar trick.