Congesting Ethereum after EIP-1559 (Full Version)

Abstract

We provide two novel block congestion attacks onEthereum that are applicable even in the presence of the EIP-1559 base fee mechanism, which aimed to make such attacksimpossible or highly costly. Unlike traditional block congestionmethods, our approaches allow the attacker to avoid paying largetransaction fees in case the attack is unsuccessful. Moreover, oursecond attack avoids an explosion in the block base fee and canthus be used for prolonged congestion of an interval of blocks.Finally, we provide real-world examples of contracts currentlydeployed on the Ethereum blockchain which are vulnerableto such attacks. Thus, block congestion is both possible andprofitable, even after EIP-1559.