Encrypted data analysis company Bitquery released an investigation report on the “51% Attack on ETC” incident. The report shows: 1. During the 12 hours from 0:30 on August 1st to 11:30 on August 2nd, ETC suffered 51% attacks. The attacks were initiated by miners starting with 0x75d1e. The miner quietly produced more than 3,500 blocks (from 10904146 to 10907740), which were then broadcast to other miners. Due to the large number of these blocks, the block sequence occupies a greater weight than the chains established by other miners, making other miners unable to This series of blocks is not accepted, and finally the attacker’s block successfully replaced the original block; 2. Not all nodes take the same behavior in this event. Nodes based on Geth and Hyperledger Besu clients accept the attacker’s block and choose the longest fork chain, while nodes based on the Open Ethereum client still retain the old chain, which leads to some miners still transferring funds based on the old chain, but in It has not been reflected on the fork chain; 3. The data on the chain shows that the miner seems to have deliberately purchased computing power from the outside to launch an attack. The miner address has only been shown as active since July 29th. In the end, the attacker spent only 17.5 BTC to implement a 12-hour attack on the entire ETC network. Lianwen previously reported that the ETC network has undergone a blockchain reorganization on August 1, and the issue of stopping block production has been resolved.