Beosin: The project SheepFarm on the BNB Chain was attacked by a vulnerability and lost about 262 BNB

According to the Beosin EagleEye security risk monitoring, early warning and blocking platform monitoring of Beosin, the project SheepFarm on the BNB Chain was attacked by a vulnerability, and lost about 262 BNB, about 72,000 US dollars. Beosin Trace found that the stolen amount is still in the attacker's account, and will continue to pay attention to the direction of the funds. Beosin analyzed the cause of the attack: because the register function of the SheepFarm contract can be called multiple times, the attacker 0x2131c67ed7b6aa01b7aa308c71991ef5baedd049 used the register function to increase his own gems multiple times, and then used the upgradeVillage function to accumulate the yield attribute while consuming gems, and finally called the sellVillage method to Convert to money before withdrawing.