majiayu000 Web3 & Blockchain Security
Overview
This skill covers Web3 security resources from the awesome-game-security collection, focusing on smart contract security, DeFi vulnerabilities, and blockchain gaming.
Smart Contract Security
Common Vulnerabilities
- Reentrancy attacks
- Integer overflow/underflow
- Access control flaws
- Front-running
- Flash loan attacks
- Oracle manipulation
- Timestamp dependence
- Unchecked external calls
Reentrancy Example
// Vulnerable
function withdraw(uint amount) public {
require(balances[msg.sender] >= amount);
(bool success, ) = msg.sender.call{value: amount}("");
require(success);
balances[msg.sender] -= amount; // State change after external call
}
// Fixed
function withdraw(uint amount) public {
require(balances[msg.sender] >= amount);
balances[msg.sender] -= amount; // State change before external call
(bool success, ) = msg.sender.call{value: amount}("");
require(success);
}
Analysis Tools
Static Analyzers
- Slither: Trail of Bits' static analyzer
- Mythril: ConsenSys security tool
- 4naly3er: Automated code analysis
- Semgrep: Pattern-based scanning
Dynamic Analysis
- Echidna: Property-based fuzzer
- Manticore: Symbolic execution
- Foundry: Testing framework with fuzzing
- Ityfuzz: EVM fuzzer
Decompilers
- ABI Decompiler: Recover contract ABI
- EthIR: Bytecode analysis framework
- Heimdall-rs: Bytecode analysis in Rust
Security Frameworks
OpenZeppelin
- Audited contract libraries
- Access control patterns
- Upgradeable contracts
- Security best practices
Development Tools
- Foundry: Modern Solidity toolkit
- Hardhat: Development environment
- Truffle: Testing framework
- Brownie: Python-based framework
DeFi Security
Attack Vectors
- Flash loan attacks
- Price oracle manipulation
- Liquidity pool attacks
- Governance attacks
- MEV extraction
Protection Mechanisms
- Time locks
- Multi-sig requirements
- Oracle diversification
- Rate limiting
- Circuit breakers
Blockchain Gaming Security
On-Chain Game Issues
- Randomness manipulation
- Front-running player actions
- Economic exploits
- NFT vulnerabilities
- Token inflation
Off-Chain Components
- API security
- Database integrity
- Asset verification
- Player identity
Audit Process
Pre-Audit Checklist
1. Complete code documentation
2. Test coverage report
3. Deployment configuration
4. Previous audit findings
5. Scope definition
Audit Methodology
1. Automated analysis (Slither, Mythril)
2. Manual code review
3. Business logic verification
4. Access control analysis
5. Economic model review
6. Integration testing
Post-Audit
1. Findings report
2. Severity classification
3. Remediation verification
4. Ongoing monitoring
Learning Resources
Practice Platforms
- Damn Vulnerable DeFi: CTF challenges
- Ethernaut: OpenZeppelin's wargame
- DeFiHackLabs: Reproduce real hacks
- DeFiVulnLabs: Learn vulnerabilities
Research
- Rekt News: Hack postmortems
- Trail of Bits Blog: Security research
- Consensys Blog: Best practices
- SlowMist: Security reports
Security Standards
EIP Standards
- EIP-20: Token standard
- EIP-721: NFT standard
- EIP-1155: Multi-token standard
- EIP-2535: Diamond standard
Audit Standards
- Smart Contract Security Verification Standard (SCSVS)
- Wallet Security Verification Standard
MEV (Miner Extractable Value)
Concepts
- Transaction ordering
- Sandwich attacks
- Arbitrage extraction
- Liquidation frontrunning
Protection
- Flashbots RPC
- Private transactions
- Commit-reveal schemes
- Time-weighted pricing
Solana Security
Unique Considerations
- Account model vs UTXO
- Program-derived addresses
- Cross-program invocation
- Rent mechanism
Tools
- Anchor framework
- Trident fuzzer
- Solana-specific analyzers
Move Language Security
Platforms
- Aptos
- Sui
- Movement
Security Features
- Resource-oriented programming
- Linear types
- Built-in formal verification
- Ability-based access control
Report Writing
Severity Levels
Critical: Direct fund loss possible
High: Significant impact, complex exploit
Medium: Limited impact or difficult exploit
Low: Best practice violations
Informational: Gas optimizations, style
Finding Format
## [Severity] Finding Title
**Description**: What the issue is
**Impact**: Potential consequences
**Location**: File and line numbers
**Recommendation**: How to fix
**Status**: Fixed/Acknowledged/Disputed