Aptos Move Security Checklist

    2025, Oct 21

    This article is a summary of the Aptos Documentation Move Security Guidelines made with ChatGPT

    Access Control

    • Verify signer ownership of all objects passed to functions.
    • Use object::owner(&obj) == address_of(user) before granting access to resources.
    • Restrict global storage access to the signer’s own address (move_from / borrow_global using signer::address_of).
    • Avoid exposing sensitive objects to any user or function.

    Function Visibility

    • Start all functions as private by default.
    • Use entry for functions callable via Aptos CLI/SDK.
    • Implement proper access control if required
    • Use public(friend) for functions accessible only by trusted modules.
    • Apply #[view] to read-only functions that should not modify state.
    • Confirm no sensitive logic is exposed through public functions unnecessarily.

    Reminder:

      Module itself Other Modules Aptos CLI/SDK
    private ☑ ☒ ☒
    public(friend) ☑ ☑if friend
    ☒ otherwise    		 ☒
    public ☑ ☑ ☒
    entry ☑ ☒ ☑

    Type Safety and Generics

    • Validate generic types explicitly; do not trust unchecked generics.
    • Use phantom type parameters to enforce type constraints where necessary.
    • Ensure loaned or returned assets match the original type (e.g., flash loans).

    Resource Management & Unbounded Execution

    • Avoid loops over globally shared structures with unbounded entries.
    • Store user-specific assets in individual user accounts.
    • Separate module/package objects from user objects to prevent interference.
    • Use efficient data structures (e.g., SmartTable) for large collections.

    Move Abilities

    • Assign copy only where duplication of data is safe.
    • Assign drop only to resources that can be safely discarded.
    • Assign store only to data meant to persist in global storage.
    • Assign key only to resources that need to be globally accessible.

    Reminder:

    Ability Description
    copy Permits the duplication of values, allowing them to be used multiple times within the contract.
    drop Allows values to be discarded from memory, which is necessary for controlling resources and preventing leaks.
    store Enables data to be saved in the global storage, critical to persist data across transactions.
    key Grants data the ability to serve as a key in global storage operations, important for data retrieval and manipulation.

    Arithmetic Safety

    • Handle integer truncation for division; ensure fees or calculations cannot round down to zero.
    • Consider integer overflow/underflow; +, -, * abort on overflow, / aborts on divide-by-zero.
    • Avoid left-shift operations that exceed integer capacity.

    Aptos Objects

    • ConstructorRef leak
      • When creating objects ensure to never expose publicly the object’s ConstructorRef as it allows adding resources to an object.
    • Keep objects in separate accounts when multiple objects are created together.
    • Prevent ownership leaks or unauthorized transfers of grouped objects.

    Business Logic Security

    • Front-running
      • Avoid multi-transaction sequences that can be manipulated.
      • Combine state changes in a single transaction where possible.
    • Price Oracle Manipulation
      • Use multiple oracles to determine prices.
      • Implement fallback mechanisms if primary oracle fails.
    • Token Identifier Collision
      • When dealing with tokens, ensure that the method for comparing token structs to establish a deterministic ordering does not lead to collisions.
      • Use unique object::object_address identifiers rather than concatenated strings.

    Reference

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