Crypto exchange Binance said late on October 6 that $100 million was likely stolen as a result of a hack on its Binance Smart Chain blockchain network, although the real figure is most likely more than half a billion.
Binance initially estimated that tokens worth about $100 m. had been taken, pausing the operation of the affected blockchain for approximately eight hours.
The exchange later disclosed, however, that the hacker had taken around two million of the cryptocurrency BNB, Binance’s own digital coin, with a value of around $284 each. The hack targeted BSC Token Hub, a bridge between two Binance systems.
Changpeng Zhao, Binance’s chief executive, said on Twitter that the issue involved the hub, a so-called cross-chain bridge. These enable the transfer of digital assets and information from one independent blockchain to another.
“The issue is contained now. Your funds are safe,” Zhao wrote, apologizing for the inconvenience.
An exploit on a cross-chain bridge, BSC Token Hub, resulted in extra BNB. We have asked all validators to temporarily suspend BSC. The issue is contained now. Your funds are safe. We apologize for the inconvenience and will provide further updates accordingly.— CZ Binance (@cz_binance) October 6, 2022
Binance said in a blog post on Friday that it was working on locking down any areas of vulnerabity.
"A new on-chain governance mechanism will be introduced on the BNB Chain to fight and defend [against] future possible attacks," the post read.
"A new on-chain governance mechanism will be introduced on the BNB Chain to fight and defend [against] future possible attacks."Changpeng Zhao
Binance also said that there would be an increase in community validators as it moves towards further decentralization. The company's position as the world’s largest crypto exchange means Friday’s exploit represents a significant blow to the digital assets industry.
$2b in cryptocurrency stolen this year
Cross-chain bridge hacks have become a common occurrence. High-profile thefts included $600 m. from the blockchain behind popular crypto-gaming platform Axie Infinity.
In August, attackers drained $190 m. worth of crypto from cross-chain bridge Nomad after a hacker exploited a vulnerability in an upgrade to the platform.
So far this year, about $2 b. in cryptocurrency has been stolen in cross-chain bridge hacks, according to blockchain data firm Chainalysis.