The attacker exploited a vulnerability in the smart contract on the Arbitrum blockchain by issuing an additional amount of Sun (SUN) tokens and exchanging them for USDT and WETH. As a result, the losses amounted to about $2.8 million. The attack began after an upgrade to the governance contract when 200 trillion SUN were created and quickly sold. The main transaction netted the attacker 2.1 million USDT, while the remaining tokens were exchanged for WETH, adding another $750,000 to the losses.
The Arbitrum network remained unharmed, but this is already the second recent attack on its contracts, following a leak of $93,000.