Trader loses $2M in ‘same-block backrun extraction’ exploitOne crypto trader noted the $2 million loss could have been prevented had the victim read the transaction route before signing the transaction.

A crypto trader experienced a substantial financial loss after swapping $2.01 million worth of Ether (ETH) on a decentralized exchange, ending up with only about $14,500 in Lighter (LIT) tokens. The loss occurred because the transaction router directed the trade through a low-liquidity pool, specifically an AVAIL/WETH pool on Uniswap v3. This routing allowed an Ethereum block builder, identified as Titan, to execute a same-block arbitrage strategy—referred to by GoPlus Security as a "textbook case of same-block backrun extraction"—and profit heavily from the trade. Titan earned approximately $1.8 million from this transaction.

The trader swapped 1,126.44 ETH but received only 5,776 LIT tokens in return. According to GoPlus Security, the victim’s transaction routed about 1,117 ETH into the low-liquidity AVAIL pool at prices roughly 120 times higher than the real AVAIL value, inflating the received token amount. The involved router, known as 0x router, then executed a maneuver selling externally sourced AVAIL into the same pool to extract 1,072 WETH, before rewarding Titan with about 1,018 ETH ($1.8 million). The leftover AVAIL was eventually swapped for about $14,200 worth of LIT tokens, resulting in an effective loss of around 99.3% for the trader.

This incident highlights ongoing risks in decentralized finance related to maximal extractable value (MEV) bots and liquidity routing practices. Crypto trader Ruslan Khairullin commented on the vulnerability, advising that traders should carefully review transaction routes before signing to avoid similar losses, noting “This is what happens when you clicked confirm faster than you read the route.” Titan, the block builder profiting from the incident, has reportedly generated $112.6 million in revenue from block building services so far this year, with its most profitable day occurring in March with a $34 million extraction from a MEV bot incident.

Cointelegraph reached out to Titan for comment but did not receive an immediate response. The event serves as a cautionary tale about the complexities and risks in the current DeFi environment where sophisticated MEV strategies can lead to large losses for unsuspecting traders.