PPTD: A Path Profiling-Based Threat Detection Method Toward Deployed Smart Contracts

Abstract

Smart contracts have been the target of attackers (e.g., identifying and exploiting vulnerabilities). Existing countermeasures for detecting threats in smart contracts include symbolic execution, formal verification, and fuzzing, most of which only target specific known threats. However, such approaches may not be effective in detecting unknown/unseen threats (e.g., those without predefined vulnerability patterns). Building on the principles of smart contract threats and the immutability property, we propose a path profiling-based threat detection (PPTD) approach. To achieve accurate tracking of cyclic and acyclic paths, PPTD combines the profiling all paths (PAP) algorithm with the efficient path profiling (EPP) algorithm to record contract execution paths. This incurs lower gas overhead while effectively detecting and preventing threats. PPTD obtains legal paths and achieves data flow level detection through fuzzer, and automatically protects vulnerable smart contracts from threats, avoiding manual modification of vulnerable codes. Specifically, our approach is also designed to detect threats and prevent attacks after the contract is deployed, as demonstrated in our evaluations.