Slither: A Static Analysis Framework For Smart Contracts

TL;DR

Slither is a static analysis framework for Ethereum smart contracts that converts Solidity code into an SSA-based intermediate form, enabling efficient vulnerability detection, optimization suggestions, and improved understanding.

Contribution

It introduces SlithIR, an SSA-based intermediate representation, and demonstrates its effectiveness in fast, accurate vulnerability detection and analysis of real-world smart contracts.

Findings

Outperforms existing tools in speed and accuracy

Effective at detecting vulnerabilities and optimization opportunities

Validated on large dataset of popular contracts

Abstract

This paper describes Slither, a static analysis framework designed to provide rich information about Ethereum smart contracts. It works by converting Solidity smart contracts into an intermediate representation called SlithIR. SlithIR uses Static Single Assignment (SSA) form and a reduced instruction set to ease implementation of analyses while preserving semantic information that would be lost in transforming Solidity to bytecode. Slither allows for the application of commonly used program analysis techniques like dataflow and taint tracking. Our framework has four main use cases: (1) automated detection of vulnerabilities, (2) automated detection of code optimization opportunities, (3) improvement of the user's understanding of the contracts, and (4) assistance with code review. In this paper, we present an overview of Slither, detail the design of its intermediate representation, and evaluate its capabilities on real-world contracts. We show that Slither's bug detection is fast, accurate, and outperforms other static analysis tools at finding issues in Ethereum smart contracts in terms of speed, robustness, and balance of detection and false positives. We compared tools using a large dataset of smart contracts and manually reviewed results for 1000 of the most used contracts.