mtarcure/claude-vibe-squad/read-only-reentrancy-check

Read-Only Reentrancy Check

Audit composable DeFi integrations for read-only reentrancy: while a protocol is mid-operation (its state temporarily inconsistent and its non-reentrant write guard held), an attacker re-enters through an ERC-721/1155/777 receiver hook or a native-transfer callback and reads a view function (price, share value, collateral ratio) that returns a skewed value, which a second consuming protocol trusts to over-borrow, mint, or liquidate.

Source: corpus A §III.3 (OWASP SC08 read-only reentrancy) — strategy-to-vault state mismatches in composable lending/AMM stacks. Impact class: funds theft / vault drain via mispriced valuation (intrinsic). Governing method: Phase-3a hypothesis lane of systematic-attacking; leads only into the verification spine.

Method

1. Identify every externally-callable view function used by other protocols for pricing/valuation

(get_virtual_price, getReserves-derived quotes, share-to-asset conversions). slither + manual mapping of cross-protocol consumers.

1. For each, check whether it can be read while the owning protocol holds only a write-side

nonReentrant guard (no read guard) during an operation that hands control to the caller (token callbacks, ETH transfers, remove_liquidity).

1. Map the consumer: a second protocol that reads that view mid-callback and acts on it (borrow,

mint, liquidate).

1. PoC on anvil --fork: trigger the owning op, re-enter via the receiver hook, read the skewed

view, and execute the over-borrow/mint on the consumer in the same transaction. Link-level negative control = the same read outside the reentrant window returns the correct value and the consumer action reverts/nets zero.

1. Add a medusa/echidna property spanning both protocols: "consumer valuation reads are never

served from an inconsistent mid-operation state."

Acceptance

• Cross-protocol valuation views are enumerated with their reentrancy-window exposure classified.
• The PoC realizes a fund loss on a real fork by reading a skewed view mid-callback; the

outside-window negative control does not.

• Finding names the view, the reentrancy window, and the consuming protocol; deduped before submission.