What it does. Perform static and symbolic analysis of Solidity smart contracts using Part of mukul975/Anthropic-Cybersecurity-Skills (817 security skills) (mukul975/Anthropic-Cybersecurity-Skills).

Install

• npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill analyzing-ethereum-smart-contract-vulnerabilities, or copy the skill folder into ~/.claude/skills/analyzing-ethereum-smart-contract-vulnerabilities/.
• Raw file: curl -sL https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/HEAD/skills/analyzing-ethereum-smart-contract-vulnerabilities/SKILL.md

SKILL.md (verbatim)

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
mitre_attack:
- T1190
- T1059

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

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.

Other files in this skill

• LICENSE
• references/api-reference.md
• scripts/agent.py

references/api-reference.md (verbatim)

API Reference: Analyzing Ethereum Smart Contract Vulnerabilities

Slither CLI

# Basic analysis
slither contracts/

# JSON output
slither contracts/ --json slither-report.json

# Run specific detector only
slither contracts/ --detect reentrancy-eth,unprotected-upgrade

# List all detectors
slither --list-detectors

# Print contract summary
slither contracts/ --print human-summary

# Generate inheritance graph
slither contracts/ --print inheritance-graph

Mythril CLI

# Analyze single contract
myth analyze contracts/Token.sol

# JSON output
myth analyze contracts/Token.sol -o json

# Set execution timeout
myth analyze contracts/Token.sol --execution-timeout 300

# Analyze deployed bytecode
myth analyze --address 0x1234... --rpc infura

# Increase analysis depth
myth analyze contracts/Token.sol --max-depth 50 --transaction-count 3

Slither Detector Severity Levels

SWC Registry (Key Entries)

Installation

# Slither (requires solc)
pip install slither-analyzer
solc-select install 0.8.20
solc-select use 0.8.20

# Mythril
pip install mythril

Slither JSON Output Structure

{
  "success": true,
  "results": {
    "detectors": [{
      "check": "reentrancy-eth",
      "impact": "High",
      "confidence": "Medium",
      "description": "Reentrancy in Contract.withdraw()",
      "elements": [{"source_mapping": {"filename_short": "Contract.sol", "lines": [42, 43]}}]
    }]
  }
}

References

• Slither: https://github.com/crytic/slither
• Mythril: https://github.com/Consensys/mythril
• SWC Registry: https://swcregistry.io/
• Solidity Security: https://docs.soliditylang.org/en/latest/security-considerations.html

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