Cronos Validators Roll Back Chain After $75M Hack

Cronos' validators took drastic measures to mitigate a $75 million hack on August 30, halting block production and rolling back over 10,000 blocks to restore the chain to its pre-exploit state.

The attack, known as a Mango-style pump-and-borrow, saw an attacker inflate the price of TONIC by 100x in just 20 minutes using $600,000. They then supplied 364.6 trillion TONIC tokens as collateral and borrowed approximately $75 million from the lending protocol Tectonic.

Tectonic's total value locked collapsed from $121.7 million to roughly $3 million within 48 hours of the exploit, with only about $6 million escaping to Ethereum before the halt.

Cronos' decision to roll back its chain has raised questions about the decentralization and immutability of blockchains, with some arguing that if a small group of validators can rewrite a chain's history, what exactly separates it from a database?