Port 8545 was used for exposing some Ethereum wallets to the public Internet without the knowledge of its owners. With a much lower price, easier to mine and easier in system resources, it became very popular. With an Internet-exposed. wallet, unauthorized fund transfers can occur, causing the unsuspecting user to lose. The only initial defense strategy against this is for the user to be mindful of their wallets, by setting a very strong password for it, preventing brute force attack against its encryption.”]
Source: https://hackercombat.com/port-8545-and-ethereum-wallets-a-very-bad-combination/