The malicious miner last week conducted a successful attack of double spending on the Bitcoin Gold network, making BTG at least the third altcoin affected by such actions.
Bitcoin Gold Communications Director, Edward Iskra, for the first time, warned users about the May 18 attack. To commit an attack, an attacker acquired about 51% hash capacity, which gave him temporary control over the network. This is a very expensive operation, however, it is recouped due to double expenditure.
The malefactor stole $ 18.6 million from crypto-exchange exchanges
After gaining control over the network, the miner began placing BTG on exchanges, while trying to send the same coins to the wallets controlled by these companies. Usually, the blockchain system solves this problem by adding only the first transaction to the block, but the attacker was able to perform the operations again, gaining control over the network.
Thus, an unknown person could place money on the exchange, and then quickly withdraw them again, after which the original transaction was canceled, and coins could be sent to another purse.
The attacked address received on May 16 388,200 BTG (most of the transactions themselves). Assuming that all of these funds were obtained through double spending, it means that the attacker stole $ 18.6 million from crypto-exchange exchanges.
Will the attack be repeated?
The last transaction was made on May 18, but the miner will be able to resume operations if he has enough power to regain control of the network.
Bitcoin Gold developers advise the exchanges to solve the problem to increase the number of required confirmations when making deposits of up to 50 blocks.
BTG is currently the 26th largest cryptocurrency with a market capitalization of $ 827 million. In addition, Bitcoin Gold is the third altcoin to be attacked last week alone.
The malicious minor manipulated two of the five hash algorithms of Verge (XVG) to obtain 35 million coins (about $ 1.75 million) in a few hours. Prior to this, the Japanese Monacoin cryptocurrency was attacked when an unknown person gained control over 57% of the network.