According to official news, Casper announced that it has fixed the testnet attack vector. It is reported that an increase in transaction volume on the testnet was found on August 7 UTC time. The investigation found that a large number of transactions were submitted within a few hours, all of which called the add_bid routine on the auction contract. The attack vector took advantage of the fact that there was no minimum value specified for the add_bid function in the auction contract, and tens of thousands of transactions calling the add_bid function were submitted on the testnet at almost zero cost, and the bid amount of these transactions was close to zero.
It is reported that Casper will increase the cost of add_bid to 3,500 CSPR and introduce a minimum bid of 10,000 CSPR, and the community does not need to take further action. No funds were stolen and the mainnet was not affected.