Anchor security checklist: 16 checks before your Solana audit

Anchor turns account validation into declarations, which removes whole classes of bugs. But Anchor only checks what you tell it to check. Run these 16 checks on any Anchor program before sending it to an auditor. This list is preparation for an audit, not a replacement for one.

Accounts and signers

• [ ] Use Signer for every account that must authorize the instruction. A plain account or UncheckedAccount is not checked for a signature.
• [ ] Tie stored authorities to the signer with has_one or an explicit constraint, for example #[account(mut, has_one = authority)].
• [ ] Justify every UncheckedAccount and AccountInfo: validate owner, key or data yourself.
• [ ] Prevent the same account being passed twice into two mutable slots, for example from.key() != to.key().

PDAs and initialization

• [ ] Validate PDAs with seeds and bump in the account constraint, and store the canonical bump.
• [ ] Design seeds so users cannot collide: include the user or the parent account.
• [ ] Avoid init_if_needed unless you have a reason, and check it cannot reset balances or owners.
• [ ] Close accounts with the close constraint instead of draining lamports by hand.

Tokens and CPIs

• [ ] Constrain token accounts by mint and authority (token::mint, token::authority or associated token constraints).
• [ ] Use Program<> or Interface<> types for programs you call, so the program ID is checked.
• [ ] Decide on Token-2022 support explicitly and review extensions such as transfer fees and transfer hooks.
• [ ] Scope PDA signer seeds tightly: separate PDAs for vaults, authorities and configuration.

Math, upgrades and testing

• [ ] Use checked arithmetic and keep overflow-checks = true in the release profile. Round in the protocol's favour.
• [ ] Validate remaining_accounts by hand: Anchor does no validation on them.
• [ ] Plan account layout changes before upgrades: version accounts or reserve space, use realloc carefully.
• [ ] Test the failure paths (wrong signer, wrong mint, duplicated accounts, zero and maximum amounts) and fuzz the rest, for example with Trident.

What to do with the results

Fix what you find, write down the invariants your program must always keep, and send both to your auditor with a frozen commit. Before mainnet, also go through the pre-launch checklist in the GitHub repository below.

Full article with FAQ: https://orivions.com/blog/anchor-security-checklist
All three checklists on GitHub: https://github.com/JakeMalarczyk/solana-security-checklists