BNB Smart Chain to hard-fork following $100M exploit


BNB Smart Chain, the smart contract-enabled blockchain of crypto exchange Binance, will undergo a hard fork as a fix for the exploit that drained the platform of an estimated $100 million on Oct. 6, according to a post on GitHub. 

The release for the mainnet and testnet is a “temporary urgent patch to mitigate the cross-chain infrastructure between Beacon Chain and Smart Chain,” said the post, aiming to reenable the cross-chain.

The hard fork, dubbed Moran, will take place at block height 22,107,423 — estimated to occur on Oct. 12 at 8:00 am UTC. Changes will include fixing a vulnerability in the iavl hash check and introducing block header in sequence checks.

While the fork does not affect regular users, node operators will have to follow a few steps, such as stopping the actual node if it’s still running and replacing it with a new binary. 

In short, a hard fork is an upgrade meant to improve a blockchain. It’s a permanent divergence from a blockchain’s most recent version, leading to a separation of the chain. As some nodes no longer meet consensus, two versions of the network run separately. In this way, it is created when one path keeps following its current set of rules while the second path follows a new set.

A vulnerability in BNB Chain’s cross-chain bridge led to its pause on Oct. 6, with attackers making off with $100 million in cryptocurrency. The exploit, perpetrated on the BSC Token Hub, created “extra BNB,” explained the company.