Cronos Erased Two Hours of Transactions to Reverse $111 Million DeFi Exploit

In brief

• Cronos says it reversed approximately $111.2 million tied to the Tectonic exploit by rolling back its blockchain.
• The intervention discarded 1 hour 54 minutes of transactions, including activity unrelated to the attack.
• Approximately $9.19 million left the network before validators halted it and remains unrecovered.

Cronos, a blockchain network backed by Crypto.com, erased nearly two hours of transaction history to reverse approximately $111.2 million tied to an exploit of lending protocol Tectonic, according to a network post-mortem on Monday.

According to the developers behind Cronos, validators reversed completed transactions to protect roughly 92% of affected funds still on the network, overriding the expectation that blockchain transactions are permanent.

“It was a hard decision, taken together with the validators, weighing the finality users expect from a chain against the funds at risk,” Cronos’ devs wrote. “Restoring state meant discarding 1 hour 54 minutes of settled transactions. The alternative, restarting without restoring state, would have left the borrowed assets in the attacker's control.”

Adding to the “hard decision” was the fact that the rollback also reversed every legitimate transaction processed during that period.