Ontology’s blockchain remained offline on September 1 after developers attributed the August 31 preventive shutdown to targeted malicious attack activity identified during a routine security check. The identity-focused public chain, known for ONT and ONG and for decentralized identity infrastructure including ONT ID, said user assets were not compromised and framed the halt as a precaution while its team and validators complete security remediation, a network upgrade, testing, and third-party assessment. Ontology set a provisional target of restoring normal operations within 24 hours and said it would issue a further announcement when the mainnet is ready. Block production stopped at block 20,770,893, created at 08:24:26 UTC, and the project announced the pause at 09:09 UTC; a 13:30:49 UTC snapshot showed a five-hour, six-minute, and 23-second gap. No on-chain transactions could be processed, Ontology EVM applications and identity-dependent services were affected, and the off-chain ONTO wallet remained available. Upbit and Bithumb suspended deposits and withdrawals for ONT, ONG, and MBL on the Ontology network while trading remained open on Upbit. The incident occurred about 10 days after Ontology’s v3.1.2 mainnet upgrade, which the network has not linked to the concern. Cronos and Injective also experienced separate disruptions around the same period, and both later resumed operations.