#What Happens When a Thief Is Outsmarted by a Bot?
When a thief is robbed themselves, it illustrates a compelling twist of fate. A criminal who managed to steal about $501,650 in USDC on the Base chain ultimately ended up with only around $129,000, thanks to an exploitative maneuver by a maximum extractable value (MEV) bot.
The incident took place at 02:29 UTC on August 6, when the stolen assets were rapidly transferred to an address controlled by the attacker. What followed was a complex narrative that showcased the intersection of criminal activity and technology.
#How Did the Attacker Miscalculate?
After securing the substantial sum of USDC, the attacker sought to convert the stolen stablecoins into wrapped ETH via a Uniswap V4 swap, a common practice among crypto thieves for quickly transitioning to more liquid assets. The critical oversight here was the attacker’s failure to implement appropriate slippage protection during the swap process. Slippage protection is designed to limit the price movement of trades, thereby preventing significant losses when market conditions fluctuate.
The lack of this safeguard allowed an MEV bot to capitalize on the unprotected swap listed in the mempool. By executing a sandwich attack, the bot placed a transaction before and after the attacker’s trade, which caused the price to increase and allowed the bot to profit substantially from the mismatch in pricing.
This resulted in the attacker receiving only 67.9 ETH, translating to a loss of 74% of the originally stolen funds. The MEV bot, on the other hand, incurred only about 3.5 ETH in gas fees to execute the attack yet managed to walk away with roughly $370,000 in profit.
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#How Did the Victim React?
In an attempt to reclaim the lost funds, the victim took the unusual step of messaging the attacker and the MEV bot operator through on-chain messages, publicly declaring the identification of the criminal. As a part of their outreach, the victim offered a 10% bounty if the stolen funds were returned. This incident caught the attention of the on-chain security firm PeckShield, who flagged the attack almost immediately. However, as of August 7, there have been no returns of the stolen assets nor any identified arrests.
The identity of the MEV bot operator remains unknown, and the exact method of phishing utilized in the attack has not been publicly detailed, raising questions around the tactics employed, whether it was a fake website, compromised application interface, or manipulation through social engineering.
#What Does This Tell Us About Base?
This incident unfolded within Base, Coinbase’s Ethereum Layer-2 network, which has seen marked growth in trading operations. It’s ironic that an individual capable of executing a phishing attack failed to leverage existing resources designed to mitigate risks related to MEV exposure, including private transaction submissions and decentralized exchange (DEX) aggregators that provide MEV protection.
At present, the attacker retains around $130,000 in ETH, the MEV bot operator enhances their wealth by approximately $370,000, and the victim remains at a $500,000 loss while desperately seeking answers on the blockchain.