The Ravencoin project the incident on Aug. 11, and warned that the vulnerability had been exploited since Aug. 7. Ravencoin flaw allowed attackers to bypass KAWPOWThe vulnerability affects validation of Ravencoin's KAWPOW block headers. That made malicious blocks dramatically cheaper to create than legitimate blocks requiring miners to perform the memory-intensive KAWPOW process. In one examined range of 2,089 blocks, the pool identified 96 affected blocks. Affected nodes could fail after restarting, while nodes attempting to synchronize with the blockchain could encounter invalid header sequences and stop syncing.