Exploiting The Laws of Order in Smart Contracts

Understand

We investigate a family of bugs in blockchain-based smart contracts, which we call event-ordering (or EO) bugs.

• These bugs are intimately related to the dynamic ordering of contract events, i.e., calls of its functions on the blockchain, and enable potential exploits of millions of USD worth of Ether.
• Known examples of such bugs and prior techniques to detect them have been restricted to a small number of event orderings, typicall 1 or 2.
• Our work provides a new formulation of this general class of EO bugs as finding concurrency properties arising in long permutations of such events.