Double-spending is a potential flaw in a digital cash scheme in which the same single digital token can be spent more than once, allowing users to execute unauthorized transactions over legitimate ones.
As indicated by security engineer Mark Nesbitt in a security alert released by Coinbase, since January 5, a series of double-spending attack has been detected on the Ethereum Classic blockchain over the last three days, prompting Coinbase to delist ETC from the exchange.
According to Nesbitt, a total of 11 illicit transactions have been carried out in which the anonymous user transferred funds from other accounts to his own.
Upon discovering the initial attack, Coinbase has placed the ETC blockchain under close surveillance, inadvertently resulting in ETC’s exclusion from its trading platform after detecting a third double-spending attack where funds were illicitly transferred.
A slew of more attacks followed thereafter, allowing attackers to execute eight more transactions, amassing a total of roughly 88,500 ETC equivalent to nearly $460,000 in just three days time.
As it stands, the attack is still ongoing. While Coinbase noted that the attackers were no longer targeting the trading platform, the exchange did not disclose whether funds were moved from another crypto exchange.
Launched in August 2016 following the now-notorious DAO attack, ETC was one of the Ethereum (ETH) network’s first forks.
At press time, ETC has plunged by almost 8 percent and is trading at $4.88, based on data aggregated by CoinMarketCap.