Blockaid stated that at least $7.5 million worth of assets were stolen in the incident, while on-chain sources indicated that the total loss exceeded $15 million. The company added that the incident was not a classic phishing attack or a traditional smart contract vulnerability in the victim’s contract.
The attack was based on tricking the bot’s mechanism for automatically evaluating seemingly profitable MEV opportunities. The attackers created fake wrapper tokens and liquidity pools, pairing fake routes such as fWETH, fUSDC, and fUSDT with fCAP tokens. These transactions appeared to the MEV bot as lucrative arbitrage opportunities.
As a result, the bot approved auxiliary contracts controlled by the attackers as addresses with spending authority. In the initial test operations, it was noted that the approvals given were immediately consumed within the route and did not leave any permanent permission behind. However, in subsequent operations, the attackers created routes that the bot approved but where this permission was neither consumed nor revoked.
*This is not investment advice.