Cronos, the public blockchain supported by Crypto.com, disclosed that, in response to an attack on the lending protocol Tectonic, network validators rolled back approximately two hours of on-chain history. Cronos stated that this action reversed around $111.2 million in related transactions, preserving most of the funds still on the chain, but also undid all legitimate transactions during that period.
The attack occurred on August 30.
According to Cronos’s post-incident review, the attacker exploited insufficient liquidity on a decentralized exchange on August 30 to inflate the price of TONIC, then borrowed approximately $120.4 million in assets across nine Tectonic markets using the inflated collateral value.
Cronos stated that validators paused the network at 9:32 AM Eastern Time, then rolled back 10,961 blocks, erasing 1 hour and 54 minutes of transaction history. The network resumed block production at 6:49 PM that evening, resulting in approximately 9 hours of downtime.
Approximately 92% of the affected funds remain on-chain.
Cronos stated that the rollback was chosen because approximately 92% of the affected funds were still within the network at the time. Without reverting to the state prior to the attack, the borrowed assets involved would remain under the attacker's control.
However, this approach also disrupted users’ usual expectation that blockchain transactions are irreversible. In its post-mortem, Cronos acknowledged that every confirmed transaction within the rollback window—regardless of whether it was related to the attack—was reversed; some applications repriced open positions after restoring the transactions.
Still, $9.19 million has been transferred out.
Although the rollback reversed most of the related operations, Cronos stated that approximately $9.19 million had already been withdrawn from the network before the halt and is therefore outside the scope of the rollback, remaining unrecovered.
Previously, external estimates suggested that the affected amount was approximately $75 million, with about $6 million transferred across chains. Cronos has now provided higher figures in its post-incident review, stating that the total borrowed amount was approximately $120.4 million, of which about $111.2 million has been reversed.
Cronos acknowledges insufficient communication during the downtime.
Cronos stated that before the network restart, validators conducted multiple rounds of coordination and resumed operations based on the same transaction history after patching the software. The project team also acknowledged insufficient external communication during the downtime.
For canceled transactions, Cronos states that users can now query them via archived records, but these records will no longer appear in the main chain history on public block explorers.
Additional context: Similar incidents have occurred before. Maya Protocol previously halted its network following an attack, and Ravencoin也曾因漏洞面临重建链历史的压力。