The unauthorized coins were indistinguishable from legitimate ZANO, leaving the team unable to remove them without rolling back the blockchain.
Source: [CoinTelegraph](https://cointelegraph.com/news/zano-exploiter-created-369m-unauthorized-zano-before-blockchain-rollback?utm_source=rss_feed&utm_medium=rss&utm_campaign=rss_partner_inbound)