Scout is an extensible open-source tool intended to assist Soroban Stellar smart contract developers and auditors detect common security issues and deviations from best practices.
This tool helps developers write secure and more robust smart contracts.
Our interest in this project comes from our experience in manual auditing and vulnerability detection in other blockchains (see Scout for ink!).
Make sure that Cargo is installed on your computer. Then, follow these 5 simple steps:
1. Install Rust Nightly Toolchain:
rustup toolchain install nightly-2023-12-162. Set Default Nightly Toolchain:
rustup default nightly-2023-12-163. Add rust-src Component:
rustup component add rust-src --toolchain nightly-2023-12-164. Install additional tools required by Scout:
cargo install cargo-dylint dylint-link mdbook5. Install Scout Audit:
cargo install cargo-scout-auditFinally, to run Scout on your project, navigate to the root directory of your smart contract (where the Cargo.toml file is) and execute the following command:
cargo scout-auditFor more information on installation and usage, please refer to the Getting Started section in our documentation section below.
Currently Scout includes the following detectors.
| Detector ID | What it Detects | Test Cases | Severity |
|---|---|---|---|
| divide-before-multiply | Performing a division operation before a multiplication, leading to loss of precision. | 1, 2, 3 | Medium |
| unsafe-unwrap | Inappropriate usage of the unwrap method, causing unexpected program crashes. | 1 | Medium |
| unsafe-expect | Improper usage of the expect method, leading to unexpected program crashes. | 1 | Medium |
| overflow-check | An arithmetic operation overflows or underflows the available memory allocated to the variable. | 1 | Critical |
| insufficiently-random-values | Avoid using block attributes for random number generation to prevent manipulation. | 1 | Critical |
| unprotected-update-current-contract-wasm | If users are allowed to call update_current_contract_wasm(), they can intentionally modify the contract behaviour. |
1 | Critical |
| avoid-core-mem-forget | The use of core::mem::forget() could lead to memory leaks and logic errors. |
1 | Enhancement |
| set-contract-storage | Insufficient access control on env.storage() method. |
1, 2, 3 | Critical |
| avoid-panic-error | Code panics on error instead of using descriptive enum. | 1 | Enhancement |
| avoid-unsafe-block | Using unsafe blocks in risks code safety and reliability. | 1 | Critical |
| dos-unbounded-operation | DoS due to unbounded operation. | 1, 2, 3 | Medium |
| soroban-version | Using an old version of Soroban can be dangerous, as it may have bugs or security issues. Use the latest version available. | 1 | Enhancement |
| unused-return-enum | Return enum from a function is not completely used. | 1, 2 | Minor |
| 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 |
| assert-violation | Avoid the usage of the macro assert!, it can panic. | 1 | Enhancement |
| unprotected-mapping-operation | Modifying mappings with an arbitrary key given by users can be a significant vulnerability. | 1, 2 | Critical |
| dos-unexpected-revert-with-vector | DoS due to improper storage. | 1 | Medium |
| unrestricted-transfer-from | Avoid passing an user-defined parameter as a from field in transfer-from. |
1 | Critical |
| unsafe-map-get | Inappropriate usage of the get method for Map in soroban |
1 | Medium |
| zero-or-test-address | Avoid zero or test address assignment to prevent contract control loss. | 1 | Medium |
| incorrect-exponentation | Warns against incorrect usage of ´^´. | 1 | Critical |
You can choose the output format that best suit your needs (html or markdown). To specify the desired output run the following command:
cargo scout-audit --output-format [html|md]
Example HTML report
Add Scout to your development workspace with Scout's VS Code extension to run Scout automatically upon saving your file.
myproject/contracts, and you want to work on the token contract while using the Scout VS Code Extension, open myproject/contracts/token.
💡 Tip: To see the errors highlighted in your code, we recommend installing the Error Lens Extension.
👉 Download Scout VS Code from Visual Studio Marketplace.
Integrate Scout into your CI/CD pipeline! Automatically run the tool against the targeted smart contracts. This immediate feedback loop allows developers to quickly address any issues before merging the code into the main branch, reducing the risk of introducing bugs or vulnerabilities.
Scout output as a comment in a pull request
👉 Find Scout GitHub Action in GitHub Marketplace.
Join us for an exciting series of video tutorials where you'll learn how to install and run Scout. Discover how to identify and resolve specific issues detected by the tool, and enhance your skills with our expert guidance.
- Introduction to Scout
- Installing Scout
- How to run Scout
- Detecting and fixing issues: Divide before multiply
- Detecting and fixing issues: Incorrect exponentiation
🎬 More videos comming soon!
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-featuresIn order to run the tests for a particular test-case, run the same command on that particular test-case folder (e.g: test-cases/divide-before-multiply/divide-before-multiply-1)
Follow our documentation links below and learn more about the vulnerabilities detected by Scout, how the tool works and how to contribute to the project!
- Getting Started
- Vulnerabilities
- Detectors
- Contribute
- Architecture
- Blog
- Precision and recall
- Scout GitHub Action
- Scout VS Code Extension
- Scout Soroban Examples
Scout for Soroban is an open source vulnerability analyzer developed by CoinFabrik's Research and Development team.
We received support through a grant from the Stellar Community Fund (SCF).
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, Stellar 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, TEAL and Stellar Soroban.
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.
Scout is licensed and distributed under a MIT license. Contact us if you're looking for an exception to the terms.