analyzing-ethereum-smart-contract-vulnerabilities - SKILL.md Agent Skill

name: analyzing-ethereum-smart-contract-vulnerabilities description: Perform static and symbolic analysis of Solidity smart contracts using Slither and Mythril to detect reentrancy, integer overflow, access control, and other vulnerability classes before deployment to Ethereum mainnet. domain: cybersecurity subdomain: blockchain-security tags:

ethereum
solidity
smart-contract
slither
mythril
blockchain
defi
audit version: '1.0' author: mahipal license: Apache-2.0 nist_csf:
PR.DS-01
PR.DS-02
ID.RA-01

Analyzing Ethereum Smart Contract Vulnerabilities

Overview

Smart contract vulnerabilities have led to billions of dollars in losses across DeFi protocols. Unlike traditional software, deployed smart contracts are immutable and handle real financial assets, making pre-deployment security analysis critical. Slither performs fast static analysis using an intermediate representation to detect over 90 vulnerability patterns in seconds, while Mythril uses symbolic execution and SMT solving to discover complex execution path vulnerabilities like reentrancy and integer overflows. This skill covers running both tools against Solidity contracts, interpreting results, triaging findings by severity, and generating audit reports.

When to Use

When investigating security incidents that require analyzing ethereum smart contract vulnerabilities
When building detection rules or threat hunting queries for this domain
When SOC analysts need structured procedures for this analysis type
When validating security monitoring coverage for related attack techniques

Detection Gaps & Validation

Vulnerability classes to cover deliberately: reentrancy (cross-function and read-only), integer overflow/underflow in pre-0.8.0 or unchecked blocks, access-control gaps (missing onlyOwner, unprotected initialize), and delegatecall / storage-collision bugs in proxies.
Tool false negatives: Slither and Mythril routinely miss bugs behind proxy patterns (EIP-1967/UUPS/Diamond) because the implementation is reached only through delegatecall. Run Slither with --compile-force-framework against the full project and point Mythril at the implementation contract directly, not the proxy.
Economic and oracle logic is invisible to static tools: price manipulation, flash-loan attack paths, slippage, and rounding abuse will not appear in detector output. These require manual review of the protocol's invariants.
How to confirm a hit (avoid false positives/negatives): turn each candidate finding into a PoC exploit on a mainnet fork using Foundry (forge test --fork-url), and assert the attacker balance actually increases or the invariant breaks. A detector flag with no working PoC stays "suspected," not "confirmed."
Don't conclude "safe" until you've run both tools, manually reviewed access control and external-call ordering, modeled economic/oracle assumptions, and fuzzed key invariants (forge test with invariant/fuzz harnesses).

Prerequisites

Python 3.10+ with pip
Slither (pip install slither-analyzer) and solc compiler
Mythril (pip install mythril) with solc-select for compiler version management
Solidity source code or compiled contract bytecode
Foundry or Hardhat development framework (optional, for project-level analysis)

Steps

Step 1: Run Slither Static Analysis

Execute Slither against the contract codebase to identify vulnerability patterns, optimization opportunities, and code quality issues using its 90+ built-in detectors.

Step 2: Run Mythril Symbolic Execution

Run Mythril deep analysis to explore execution paths and discover reentrancy, unchecked external calls, and arithmetic vulnerabilities that require path-sensitive analysis.

Step 3: Triage and Correlate Findings

Combine results from both tools, deduplicate findings, assess severity based on exploitability and financial impact, and filter false positives.

Step 4: Generate Audit Report

Produce a structured audit report with vulnerability descriptions, affected code locations, exploit scenarios, and remediation recommendations.

Expected Output

JSON report listing vulnerabilities with SWC (Smart Contract Weakness Classification) identifiers, severity ratings, affected functions, and suggested fixes.