Analyzing Ethereum Smart Contract Vulnerabilities

---
name: analyzing-ethereum-smart-contract-vulnerabilities
description: Use when 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. Use when
  performing static and symbolic analysis of solidity smart contracts using.
domain: cybersecurity
subdomain: blockchain-security
tags:
- ethereum
- solidity
- smart-contract
- slither
- mythril
- blockchain
- defi
- audit
version: '1.0'
author: oyi77
license: Apache-2.0
nist_csf:
- PR.DS-01
- PR.DS-02
- ID.RA-01
category: cybersecurity
---


# 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
**Trigger phrases:**
- "analyzing ethereum smart contract vulnerabilities"
- "Perform static and symbolic analysis of Solidity smart contracts using Slither a"


- 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

```python
# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}
```

1. **Scope the task** — define objectives, boundaries, and success criteria
2. **Gather information** — collect all necessary data and context before proceeding
3. **Execute the core workflow** — follow the domain-specific steps methodically
4. **Validate results** — verify outputs against expected outcomes or baselines
5. **Document findings** — record results, anomalies, and recommendations
### 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.
## When NOT to Use

- You need to perform the attack, not analyze it (use performing-* skills)
- Task is about detection, not analysis (use detecting-* skills)
- You need to implement controls (use implementing-* skills)
- Task is about threat hunting, not post-incident analysis (use hunting-* skills)
- You don't have access to the artifacts/logs to analyze
- Task requires real-time monitoring (use SOC tools)


## Red Flags

- Performing actions without explicit written authorization from the asset owner
- Testing against production systems without a defined scope and rules of engagement
- Sharing sensitive findings or credentials in unencrypted communications
- Failing to properly scope and contain the assessment before starting

## Process

1. **Reconnaissance** — Gather target information, identify attack surface, enumerate services
1. **Analysis/Exploitation** — Execute the technique, analyze results, document findings
1. **Reporting** — Document IOCs, write findings, provide remediation recommendations

## Verification

- All steps executed successfully against a test environment before production use
- Output documented with screenshots or logs demonstrating expected behavior
- Results validated against known-good baselines or reference implementations
- Documentation complete enough for another analyst to reproduce findings

## Anti-Rationalization Table

| Rationalization | Reality |
|---|---|
| "We are too small to be targeted" | Automated attacks target everyone. Size does not matter. |
| "Security slows us down" | A breach slows you down 100x more. Build security in from the start. |
| "We will fix it after launch" | Vulnerabilities in production are exploited within hours. Fix before deploy. |