The Juno blockchain based on Cosmos suspended work on April 5 due to a cyber attack on the network. Juno developers claim that user funds have not been affected.
It is reported that the failure of the blockchain occurred due to a vulnerable smart contract, which was disguised as a “Hello World” program.
An unknown attacker sent a string of more than 400 transactions to a smart contract. By trial and error in 3 days, the hacker was able to pick up a combination of transactions that led to a network failure.
According to the developer, the attacker took advantage of a blockchain vulnerability that Juno planned to eliminate during the next update.
The team informed all partners about the vulnerability, since the exploit affected all blockchains using the CosmWasm smart contract platform.