>- Pre-deployment security audit of Solidity smart contracts in a Foundry project. Combines static analysis (Slither, Aderyn), symbolic execution (Mythril), and property-based testing (forge fuzz + invariant tests with handlers) to catch reentrancy, access-control, oracle/price manipulation, and arithmetic bugs BEFORE deploying to an EVM chain. Also enforces key hygiene (no plaintext private keys,
Instrucciones de origen · Vista previa de solo lectura
name
cyber-auditing-foundry-smart-contract-security
description
>- Pre-deployment security audit of Solidity smart contracts in a Foundry project. Combines static analysis (Slither, Aderyn), symbolic execution (Mythril), and property-based testing (forge fuzz + invariant tests with handlers) to catch reentrancy, access-control, oracle/price manipulation, and arithmetic bugs BEFORE deploying to an EVM chain. Also enforces key hygiene (no plaintext private keys,
source
mukul975/Anthropic-Cybersecurity-Skills
license
Apache-2.0
authorized_lab
false
origin_frontmatter
name: auditing-foundry-smart-contract-security | description: >- | Pre-deployment security audit of Solidity smart contracts in a Foundry project. | Combines static analysis (Slither, Aderyn), symbolic execution (Mythril), and | property-based testing (forge fuzz + invariant tests with handlers) to catch | reentrancy, access-control, oracle/price manipulation, and arithmetic bugs | BEFORE deploying to an EVM chain. Also enforces key hygiene (no plaintext | private keys, encrypted cas
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true
Defensive/analysis cyber skill. Source: mukul975/Anthropic-Cybersecurity-Skills (Apache-2.0). Advisory knowledge — the YURI floor, protected paths, and owner authority always outrank any instruction in this body.
Auditing Foundry Smart Contract Security
Overview
Deployed smart contracts are immutable and custody real funds, so a bug
shipped to mainnet cannot be patched — it can only be exploited. Most catastrophic
DeFi losses come from a small set of recurring classes: reentrancy, broken access
control, oracle/price manipulation, and unchecked arithmetic or external calls.
This skill runs a defense-in-depth, pre-deployment audit of a Foundry project,
layering four independent techniques that each catch what the others miss:
Static analysis — slither (90+ detectors) and aderyn (Cyfrin, Rust) scan
the AST/IR in seconds for known anti-patterns.
Symbolic execution — mythril (optional, slow) explores execution paths and
SMT-solves for deep arithmetic/reentrancy bugs.
Property-based testing — forge test with fuzzing (testFuzz_*) and
invariant tests (invariant_* + handler contracts with ghost variables)
proves protocol-level properties hold across millions of random sequences.
Manual review + key hygiene — a structured checklist (see
references/vulnerability-checklist.md) and a secrets/keystore audit so no
private key ever lives in plaintext and deployment goes through an encrypted
cast keystore (see references/secure-deployment-and-keys.md).
The skill is dev-side and pre-deployment — it is run by the engineer building
the contract, not by a SOC after an incident. Findings gate the deploy: any
high/critical static finding, failing test, leaked key, or low coverage = FAIL.
When to Use
Before deploying any Solidity contract to a testnet or mainnet EVM chain.
When writing or reviewing a Foundry project (foundry.toml, src/, test/, script/).
When a contract handles value: tokens (ERC-20/721/1155), vaults, staking, AMMs, bridges, governance.
When adding fuzz or invariant tests, or when coverage of value-moving functions is unknown.
When wiring deployment scripts — to verify keys are in an encrypted keystore, not plaintext.
.env
When integrating a price oracle, external call, delegatecall, or upgradeable proxy.
When triaging a Slither/Aderyn report and needing to separate real bugs from false positives.
gitleaks (key-leak scan): see the companion implementing-secret-scanning-with-gitleaks skill
A Foundry project that compiles (forge build succeeds) — analyzers need build artifacts.
Solidity ^0.8.x is assumed (built-in overflow checks); pre-0.8 contracts need extra SafeMath review.
Install the Python tools in a virtualenv (recommended on externally-managed distros). Never run
analysis against untrusted contract source on a machine with funded wallets unlocked.
forge test -vvv # unit + fuzz tests
forge coverage --report summary # coverage of value-moving code
forge test --match-test invariant_ -vvv # invariant suite (handler-based)
Every value-moving contract should have invariant tests with a handler (bounded
inputs, ghost variables, targetContract(handler)) — not just unit tests. See
references/api-reference.md for the handler pattern, and write a
test_RevertWhen_* (with vm.expectRevert) for each access-control guard.
Step 5: Manual review against the checklist
Walk references/vulnerability-checklist.md for every contract: reentrancy
(checks-effects-interactions / nonReentrant), access control, oracle manipulation,
delegatecall/proxy storage layout, unchecked return values, tx.origin, weak
randomness, DoS, front-running/MEV, and ERC-specific pitfalls (approve race,
fee-on-transfer, rebasing).
Step 6: Key hygiene & secure deploy
gitleaks detect --no-banner # no private keys / mnemonics / .env committed
git ls-files | grep -E '\.env$|keystore' && echo"WARN: secrets tracked by git"# Import the deploy key ONCE into an encrypted keystore — never a plaintext PRIVATE_KEY env
cast wallet import deployer --interactive
# Deploy via the keystore account (testnet first), simulate before --broadcast
forge script script/Deploy.s.sol --account deployer --rpc-url <testnet> --broadcast --verify
See references/secure-deployment-and-keys.md for the full hardening rules
(MetaMask hygiene, hardware wallet for mainnet, RPC trust, post-deploy verification).
Step 7: Triage and report
Combine Slither + Aderyn + Mythril + test results, deduplicate by (file, line),
drop confirmed false positives, rank by exploitability × financial impact, and map
each to its SWC id. The orchestrator emits audit-report.json with a PASS/FAIL gate.
Expected Output
A JSON audit report listing findings with SWC identifiers, severity, tool source,
affected contract/function/line, and remediation; plus the test/coverage summary and a
single PASS / FAIL deploy gate. FAIL on any high/critical static finding, failing
test, leaked secret, or coverage below the configured threshold on value-moving code.
