Today the STEEM blockchain got hit with an attack aimed at disrupting its usual functionality. Particularly by stalling steemd nodes causing witnesses to miss blocks.

The Big One

Numerous witnesses missed blocks because of the size of the transaction that is being broadcast. The blockchain rejected those blocks, causing witnesses to fail at processing normal transactions.

The transaction is as follows:

{"trx":{"ref_block_num":4943,"ref_block_prefix":2623990396,"expiration":"2018-04-23T20:49:12","operations":[["custom_json",{"required_auths":["notahotdog"],"required_posting_auths":[],"id":"nothotdog0.2866754495943664","json":"["biggadicka",{"data":"BiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKaBiGGaDiCKa....

The Culprit

The account the attack was launched from is @notahotdog and the actual attack consisted of sending a long custom JSON transaction as seen here:

Looking forward to check in on steem.chat and github for a potential node update as soon as possible.