Hackers launch third 51% attack on ETC this month, OK suffers heavy losses

In August, hackers gained control of the Ethereum Classic (ETC) blockchain in a 51% attack for the third time , reorganizing more than 7,000 blocks.
Although Ethereum Classic developers are rushing to protect the blockchain from future attacks, the three attacks have raised concerns about the security of the network. For example, OKEx has considered delisting the coin to protect itself from future losses.
What is a 51% attack?
Hackers conduct 51% attacks to take over blockchains. Blockchain is a decentralized ledger that distributes all the work of verifying transactions across a global network of computers, called miners. Each transaction must be approved by more than 51% of miners. So in theory, it is difficult for a single actor to control 51% of the network because it requires huge computing power.
But if someone manages to gain control of the network, they can bend the blockchain to their will — for example, by topping up their own accounts with free cryptocurrency or diverting other people’s transactions to their own wallets.
The latest attack took place last night, with hackers brute-force taking control of the majority of the network again and successfully reorganizing more than 7,000 blocks, or about two days of mining time.
The attack was also discovered by Austrian mining company Bitfly, which also discovered the first and second attacks, in which hackers reorganized nearly 8,000 blocks and transferred about $9 million in trading coins, most of which came from crypto exchange OKEx.
The ETC Cooperative, a nonprofit that monitors the Ethereum Classic blockchain, tweeted late last night that it is “aware of the severity of the attack and is working with others to test and evaluate proposed solutions as quickly as possible.”
After the first two attacks earlier this month, OKEx said it would "consider delisting ETC pending the results of the Ethereum Classic community's work to improve its on-chain security." This is because according to an August 15 statement, OKEx suffered heavy losses in the first attack, suffering a loss of approximately $5.6 million in ETC.
According to OKEx's user protection policy, the loss was borne entirely by OKEx, and no losses were caused to platform users. The ETC deposited by users on OKEx remains safe.
Now, Ethereum Classic developers must plug the loophole before OKEx takes action. (Baijiahao)