DeFi Protocol Review Skill

You are performing a specialized security review of a DeFi protocol on Solana. This skill extends the base security-audit with domain-specific checks for financial primitives: AMM constant-product invariants, lending collateral ratios, oracle price manipulation vectors, flash loan attack surfaces, and liquidation logic correctness.

Context Sources

| Source | Path | Contains |

|--------|------|----------|

| Vulnerability Rules | programs/parity/src/context_engine.rs > VULNERABILITY_RULES | Base pattern database |

| Curated Audit Findings | programs/parity/src/context_engine.rs > CURATED_AUDIT_FINDINGS | Real DeFi vulnerabilities from public audits |

| Security Audit Skill | skills/security-audit/SKILL.md | Base security checks (run these first) |

| Token Analyzer Skill | skills/token-analyzer/SKILL.md | Token-specific checks for SPL/Token-2022 interactions |

GitHub base URL: https://github.com/paritydotcx/Skills/blob/main/

Step 1: Protocol Classification

Identify the protocol type by analyzing instruction handlers and account structures:

Classify the protocol and apply the relevant domain-specific checks below.

Step 2: Oracle Price Feed Validation (Critical)

If the protocol uses external price data, verify:

- Price is read from an AMM pool's reserve ratio (not an oracle)

- No TWAP or multi-block averaging is used

- The price influences a high-value operation (liquidation, borrowing, swap)

Vulnerable pattern:

// VULNERABLE: reads pool reserves as price, manipulable via flash loan
let price = pool.reserve_a as u128 * PRECISION / pool.reserve_b as u128;

Secure pattern:

// SECURE: Pyth oracle with staleness and confidence checks
let price_feed = ctx.accounts.oracle.load_price_feed()?;
let current_price = price_feed.get_price_no_older_than(clock.unix_timestamp, MAX_ORACLE_AGE)?;

require!(
    current_price.conf as u64 * 100 / current_price.price.unsigned_abs() < MAX_CONFIDENCE_PCT,
    ErrorCode::OraclePriceUnreliable
);

Finding if violated:

Step 3: AMM Invariant Checks (Critical)

For AMM/DEX protocols, verify:

Finding if violated:

Step 4: Lending Protocol Checks (Critical)

For lending protocols, verify:

Finding if violated:

Step 5: Flash Loan Attack Surface (Critical)

Analyze whether any operation can be exploited within a single transaction:

- Read pool reserves, manipulate with flash loan, execute swap at manipulated price, repay flash loan

- Read collateral value, inflate via flash loan deposit, borrow against inflated value, withdraw collateral

Finding if applicable:

Step 6: Liquidation Logic (High)

If the protocol has liquidation:

Finding if violated:

Step 7: Economic Invariants (High)

Check protocol-wide invariants that must always hold:

Identify whether these invariants are enforced on-chain or only implicitly assumed.

Finding if violated:

Scoring

| Severity | Penalty per finding |

|----------|-------------------|

| Critical | -25 |

| High | -15 |

| Medium | -8 |

| Info | -3 |

Start at 100. Subtract penalties. Floor at 0.

Output Format

{
  "score": 38,
  "defi_surface": {
    "protocol_type": "lending",
    "oracle_type": "pyth",
    "has_flash_loan": false,
    "has_liquidation": true,
    "token_standard": "spl-token",
    "attack_vectors_identified": ["oracle_staleness", "partial_liquidation_missing"]
  },
  "findings": [
    {
      "severity": "critical",
      "title": "Oracle price staleness not enforced in borrow instruction",
      "location": { "file": "lib.rs", "line": 134, "instruction": "borrow" },
      "description": "The Pyth price feed is read without a staleness check. An attacker could borrow against a stale price during high volatility.",
      "recommendation": "Add get_price_no_older_than(clock.unix_timestamp, 30) to reject prices older than 30 seconds."
    }
  ],
  "summary": "Lending protocol with 2 critical (oracle, collateral ratio), 1 high (liquidation). Flash loan surface: low (no pool-based pricing). Primary risk: oracle manipulation during borrow."
}