Cosmos Downtime Exposes Complexities of Blockchain Consensus

A recent incident involving Cosmos's 25-hour downtime has shed light on the complexities of blockchain consensus.

The event began when a user initiated an ATOM transfer on September 22, but the transaction remained stuck in 'waiting for confirmation' overnight.

When checking again the next day, multiple public RPCs indicated that Cosmos Hub had halted at block height 33,086,740.

No private key was lost and the wallet showed no signature anomalies. The halt wasn't due to a direct attack on Cosmos Hub, but rather the subsequent cross-chain fund transfer of approximately 1.7 million ATOM into the Hub.

Some validators took their nodes offline, preventing new blocks from being produced and causing the network to come to a standstill.

The halt was eventually resolved when validators received a recovery plan and installed a patch that executed a one-time state modification at the designated recovery height. This transferred 1,227,121 ATOM from the attacker's address into a multi-signature address jointly managed by community validators.