Once hailed as unhackable, blockchains are now getting hacked
Early last month, the security team at Coinbase noticed something strange going on in Ethereum Classic, one of the cryptocurrencies people can buy and sell using Coinbase’s popular exchange platform. Its blockchain, the history of all its transactions, was under attack.
An attacker had somehow gained control of more than half of the network’s computing power and was using it to rewrite the transaction history. That made it possible to spend the same cryptocurrency more than once—known as “double spends.” The attacker was spotted pulling this off to the tune of $1.1 million.
Blockchains are particularly attractive to thieves because fraudulent transactions can’t be reversed as they often can be in the traditional financial system. Besides that, we’ve long known that just as blockchains have unique security features, they have unique vulnerabilities. Marketing slogans and headlines that called the technology “unhackable” were dead wrong.
But the more complex a blockchain system is, the more ways there are to make mistakes while setting it up.