Who Is Pulling the Strings: Unveiling Smart Contract State Manipulation Attacks Through State-Aware Dataflow Analysis

Abstract

Recently, the increasing complexity of smart contracts and their interactions has led to more sophisticated strategies for executing attacks. Hackers often need to deploy attacker contracts as delegators to automate these attacks on their behalf. Existing identification methods for attacker contracts either rely on simple patterns (e.g., recursive callback control flow) that suffer from high false-positive rates and limited extraction of interaction and call information, or lack fully automated detection capabilities. Consequently, these limitations reduce the effectiveness of current solutions in identifying modern, intricate attacks. To overcome these challenges, we introduce the concept of state manipulation attacks, which abstracts the exploitation of problematic state dependencies arising from contract interactions. During these attacks, hackers first alter the storage state of one contract (the manipulated contract), which determines the profit they can gain. They then call another contract (the victim contract) to exploit its dependency on the altered state and maximize their profits. We present SMAsher, a tool designed to automatically identify state manipulation attacker contracts. SMAsher leverages fine-grained state-aware dataflow analysis to detect exploitation traces and exploited state dependencies among contracts, focusing on recovering the call path and interaction semantics. Our extensive experiments on 1.38 million real-world contracts demonstrate that SMAsher successfully identifies 311 state manipulation attacker contracts with 100% precision, resulting in $ 6.95 million in losses. Our findings also reveal some notable malicious characteristics of hackers’ accounts through their deployed attacker contracts. Additionally, we have provided 10 PoCs (Proof-of-Concepts) for previously unidentified attacks, all of which have been confirmed and released to the community.