substrate-vulnerability-scanner

Audit Substrate pallets by checking each dispatchable for the 7 critical patterns: unchecked arithmetic, panics from unwrap or indexing, fixed weights on variable-cost operations, storage writes before validation, weak unsigned transaction validation, insecure randomness, and ensure_signed on privileged calls. This Skill walks through each pattern with detection commands and fixes.

Replace direct +, -, *, / operators with checked_* or saturating_* methods from sp_runtime traits. In release mode Rust primitives wrap silently, so balance and reward calculations must use checked_sub, checked_mul, or saturating_add and return DispatchError on overflow.

A panic in a dispatchable stops the node from processing blocks, letting attackers halt the chain with crafted inputs. Avoid unwrap(), expect(), unchecked array indexing, and division by zero; validate all user input with ensure! and return DispatchError instead.

Use ensure_root or custom origins like ForceOrigin for privileged operations such as emergency pause, fee updates, or force transfers. ensure_signed only proves some account signed, so any user could invoke admin functions if it guards privileged calls.

Yes, v0.9.25 introduced a transactional storage layer that rolls back writes when a dispatch fails. On earlier versions you must validate before writing or add the #[transactional] attribute manually to prevent state corruption on error.

Use BABE randomness via pallet_babe::RandomnessFromOneEpochAgo for production. pallet_randomness_collective_flip is vulnerable to validator collusion, and on-chain randomness should never be used to generate cryptographic keys.