Scout: Security Analysis Tool

Scout is an extensible open-source tool intended to assist ink! smart contract developers and auditors detect common security issues and deviations from best practices.

This tool will help developers write secure and more robust smart contracts.

Our interest in this project comes from our experience in manual auditing and our usage of comparable tools in other blockchains. To improve coverage and precision, we´ll persist in research efforts on static and dynamic analysis techniques. Find more about our ongoing research at our associated repository.

Quick Start

For a quick start, make sure that Cargo is installed on your computer. Then, install Scout dependencies by running the following command:

cargo install cargo-dylint dylint-link

Afterwards, install Scout with the following command:

cargo install cargo-scout-audit

To run Scout on your project, navigate to its root directory and execute the following command:

cargo scout-audit

For more information on installation and usage, please refer to the Getting Started section in our documentation below.

Documentation

• Getting Started
• Vulnerabilities
• Detectors
• Contribute
• Architecture
• Blog

Visit Scout's website to view the full documentation.

Detectors

Detector ID	What it Detects	Test Cases	Severity
integer-overflow-or-underflow	An arithmetic operation overflows or underflows the available memory allocated to the variable.	1, 2	Critical
set-contract-storage	Insufficient access control on set_contract_storage() function.	1	Critical
reentrancy	Consistency of contract state under recursive calls.	1, 2, 3	Critical
panic-error	Code panics on error instead of using descriptive enum.	1	Enhancement
unused-return-enum	Return enum from a function is not completely used.	1	Minor
dos-unbounded-operation	DoS due to unbounded operation.	1	Medium
dos-unexpected-revert-with-vector	DoS due to improper storage.	1	Medium
unsafe-expect	Improper usage of the expect method, leading to unexpected program crashes.	1	Medium
unsafe-unwrap	Inappropriate usage of the unwrap method, causing unexpected program crashes.	1	Medium
divide-before-multiply	Performing a division operation before a multiplication, leading to loss of precision.	1	Medium
delegate-call	Invoking code in another contract keeping the first contract's context.	1	Critical
zero-or-test-address	Avoid zero or test address assignment to prevent contract control loss.	1	Medium
insufficiently-random-values	Avoid using block attributes for random number generation to prevent manipulation.	1	Critical
unrestricted-transfer-from	Avoid passing an user-defined parameter as a from field in transfer-from	1	Critical
assert-violation	Avoid the usage of the macro assert!, it can panic.	1	Enhancement
avoid-core-mem-forget	The use of core::mem::forget could lead to memory leaks and logic errors	1	Enhancement
avoid-format-string	The format! macro is not recommended. A custom error is recommended instead.	1	Enhancement
unprotected-self-destruct	If users are allowed to call terminate_contract, they can intentionally or accidentally destroy the contract.	1	Critical
iterators-over-indexing	Iterating with hardcoded indexes is slower than using an iterator. Also, if the index is out of bounds, it will panic.	1	Enhancement
ink-version	Using an old version of ink! can be dangerous, as it may have bugs or security issues. Use the latest version available.	1	Enhancement
unprotected-set-code-hash	If users are allowed to call terminate_contract, they can intentionally modify the contract behaviour.	1	Critical
unprotected-mapping-operation	Modifying mappings with an arbitrary key given by the user could lead to unintented modifications of critical data, modifying data belonging to other users, causing denial of service, unathorized access, and other potential issues.	1	Critical
lazy-delegate	Delegated calls in ink! need lazy storage.	1	Critical

Tests

To validate our tool, we provide a set of code examples located in the test-cases folder.

In order to run the integration tests, navigate to apps/cargo-scout-audit and run:

cargo test --all --all-features

In order to run the tests for a particular test-case, run the same command on that particular test-case folder (e.g: test-cases/delegate-call/delegate-call-1/vulnerable-example)

Acknowledgements

Scout is an open source vulnerability analyzer developed by CoinFabrik's Research and Development team.

We received support through grants from both the Web3 Foundation Grants Program and the Aleph Zero Ecosystem Funding Program.

Grant Program	Description
	Proof of Concept: We collaborated with the Laboratory on Foundations and Tools for Software Engineering (LaFHIS) at the University of Buenos Aires to establish analysis techniques and tools for our detectors, as well as to create an initial list of vulnerability classes and code examples. View Grant | Application Form. Prototype: We built a functioning prototype using linting detectors built with Dylint and expanded the list of vulnerability classes, detectors, and test cases. View Prototype | Application Form.
	We improved the precision and number of detectors for the tool with a multi-phase approach. This included a manual vulnerability analysis of projects within the Aleph Zero ecosystem, comprehensive testing of the tool on leading projects, and refining its detection accuracy.

About CoinFabrik

We - CoinFabrik - are a research and development company specialized in Web3, with a strong background in cybersecurity. Founded in 2014, we have worked on over 180 blockchain-related projects, EVM based and also for Solana, Algorand, and Polkadot. Beyond development, we offer security audits through a dedicated in-house team of senior cybersecurity professionals, currently working on code in Substrate, Solidity, Clarity, Rust, and TEAL.

Our team has an academic background in computer science and mathematics, with work experience focused on cybersecurity and software development, including academic publications, patents turned into products, and conference presentations. Furthermore, we have an ongoing collaboration on knowledge transfer and open-source projects with the University of Buenos Aires.

License

Scout is licensed and distributed under a MIT license. Contact us if you're looking for an exception to the terms.