Ethereum Classic [ETC] has suffered a 51% attack for the third time in a month following which reorganization of over 7000 blocks occurred on the network which corresponded to approximately two days of mining.
A chain reorganization takes place when a party gains more hashing power than the rest of the miners in the network. The offending miner then achieves the ability to rewrite the chain’s history and also “double-spend” the blockchain’s native token. The double spends made in the latest attack is not known yet.
A leading organization behind the Ethereum Classic network, ETC Labs called the entire fiasco “suspicious” as it occurred a day after the core-dev meeting.
Today another large 51% attack occurred on the #ETC network which caused a reorganization of over 7000 blocks which corresponds to approximately 2 days of mining. All lost blocks will be removed from the immature balance and we will check all payouts for dropped txs.
— Bitfly (@etherchain_org) August 29, 2020
The 51% attack was first spotted by the mining pool Ethermine’s parent entity Bitfly which revealed that all the lost blocks will be removed from the immature balance and that the platform will check all payouts for dropped transactions.
Ethereum Classic official Twitter handle also responded and tweeted,
“While ETC is still making progress in evaluating proposed solutions, we are aware of the current risk to the network at these low hash rate levels. To miners, exchanges, and other service providers we suggest keeping confirmation requirements levels well above 7K for now.”
Following the attack, Ethereum Classic’s hash rate which was declined significantly over the past couple of months was down by 4.77% in the last 24 hours. At 3.78 Th/s, the hash rate was still hovering close to its three-year low.
ETC Cooperative, which happens to be another prominent foundation supporting ETC network’s development also addressed the recent turn of events and tweeted,
“We are aware of today’s attack and are working with others to test and evaluate proposed solutions as quickly as possible. As ETC makes progress in areas, it still makes up just ~3% of ETH’s hash rate. We kindly ask that miners, exchanges, and others raise confirmations to >12K.”
The network suffered its first 51% attack of the year between July 29 and August 1, when 3,693 blocks were reorganized. Less than a week later 4,000 blocks were reorganized after the network was hit by the second attack. During this time, the adversary was able to double-spend 807,260 ETC [nearly $5.6 million, at that time] after spending 17.5 BTC [around $200,000] to acquire the hash power for the attack.
In light of these events, cryptocurrency exchange, OKEx had revealed that it was considering the removal of the asset.
The series of attacks pertaining to the network insecurity has pushed ETC’s price further down the bearish region as it was down by nearly 50% since February this year. Notably, ETC had suffered a similar attack in 2019.