Guard CLI

Static analysis engine for Soroban smart contracts — securing the Stellar blockchain, one contract at a time.

Guard CLI is a CLI-based static analyzer for Rust smart contracts deployed on the Stellar network via the Soroban smart contract platform. It detects vulnerabilities before your code ever touches the chain.

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Why Soroban Guard?

Soroban is Stellar's smart contract platform — a WebAssembly-based execution environment designed for speed, low cost, and predictability. But like any smart contract platform, bugs in Soroban contracts can be exploited on-chain and are irreversible.

Soroban Guard catches common vulnerability classes at the source level, before stellar contract deploy ever runs.

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Stellar / Soroban Context

Soroban contracts are Rust crates compiled to WASM and deployed to the Stellar network. Key security concerns this tool addresses:

Concern	Stellar/Soroban Impact
Missing require_auth	Any caller can invoke privileged contract functions
Unchecked arithmetic	Integer overflow/underflow in token balances or ledger math
Unprotected admin	Admin keys can be overwritten without authorization
Unsafe storage patterns	Persistent/temporary ledger storage misuse

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Requirements

• Rust 1.74+ (2021 edition)
• No Stellar SDK or network connection required — analysis is purely static

Build

cargo build --release

The binary is target/release/soroban-guard (package soroban-guard-cli).

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Usage

Scan a Soroban contract crate before deploying to Stellar:

cargo run -p soroban-guard-cli -- scan ./path/to/contract-crate

Output as JSON (useful for CI pipelines or the web dashboard):

cargo run -p soroban-guard-cli -- scan ./path/to/contract-crate --json

Write JSON to a file instead of stdout:

cargo run -p soroban-guard-cli -- scan ./path/to/contract-crate --json --output findings.json

Emit SARIF 2.1.0 for GitHub Code Scanning:

cargo run -p soroban-guard-cli -- scan ./path/to/contract-crate --sarif > findings.sarif

List the checks that run by default:

cargo run -p soroban-guard-cli -- list-checks

For plain terminal output, disable ANSI colors with:

NO_COLOR=1 soroban-guard scan ./path/to/contract-crate

Exit codes

Code	Meaning
0	No High severity findings — safe to proceed
1	At least one High finding — do not deploy
2	Scan error (I/O or parse failure)

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Workspace Scaffold

See Architecture for the crate dependency graph, scan data flow, key types, and extension points.

Guard-CLI/
├── Cargo.toml                  # workspace root
├── crates/
│   ├── cli/                    # clap entrypoint & reporting
│   │   └── src/main.rs
│   ├── analyzer/               # walks .rs files, parses with syn, runs checks
│   │   └── src/lib.rs
│   └── checks/                 # Check trait + individual detectors
│       └── src/
│           ├── lib.rs          # trait definition, Finding, Severity, default_checks()
│           ├── auth.rs         # missing-require-auth
│           ├── overflow.rs     # unchecked-arithmetic
│           ├── admin.rs        # unprotected-admin
│           └── storage.rs      # unsafe-storage-patterns
└── test-contracts/             # standalone Soroban crates (excluded from workspace)
    ├── vulnerable/             # triggers missing-require-auth
    ├── safe/                   # passes missing-require-auth
    ├── arithmetic-vulnerable/
    ├── arithmetic-safe/
    ├── admin-vulnerable/
    ├── admin-safe/
    ├── storage-vulnerable/
    └── storage-safe/

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Code Snippets

Vulnerable contract — triggers missing-require-auth

#![no_std]
use soroban_sdk::{contract, contractimpl, symbol_short, Env, Symbol};

#[contract]
pub struct VulnerableContract;

const KEY: Symbol = symbol_short!("counter");

#[contractimpl]
impl VulnerableContract {
    // ❌ No env.require_auth() — anyone on Stellar can call this
    pub fn bump(env: Env) {
        let mut n: u32 = env.storage().instance().get(&KEY).unwrap_or(0);
        n += 1;
        env.storage().instance().set(&KEY, &n);
    }
}

Safe contract — passes missing-require-auth

#![no_std]
use soroban_sdk::{contract, contractimpl, symbol_short, Address, Env, Symbol};

#[contract]
pub struct SafeContract;

const KEY: Symbol = symbol_short!("owner");

#[contractimpl]
impl SafeContract {
    // ✅ Caller must be the authorized Address on Stellar
    pub fn set_owner(env: Env, new_owner: Address) {
        env.require_auth();
        env.storage().instance().set(&KEY, &new_owner);
    }
}

Adding a custom check

Implement the Check trait in crates/checks/src/ and register it in default_checks():

use crate::{Check, Finding};
use syn::File;

pub struct MyCustomCheck;

impl Check for MyCustomCheck {
    fn name(&self) -> &str { "my-custom-check" }

    fn run(&self, file: &File, source: &str) -> Vec<Finding> {
        // inspect the syn AST and return any findings
        vec![]
    }
}

// crates/checks/src/lib.rs — register it here
pub fn default_checks() -> Vec<Box<dyn Check + Send + Sync>> {
    vec![
        Box::new(MissingRequireAuthCheck),
        Box::new(UncheckedArithmeticCheck),
        Box::new(UnprotectedAdminCheck),
        Box::new(UnsafeStoragePatternsCheck),
        Box::new(MyCustomCheck),   // 👈 add your check
    ]
}

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Stellar Integration

Guard CLI is designed to sit at the gate of your Stellar deployment pipeline. Soroban contracts are compiled to WASM and deployed to the Stellar network — Guard CLI catches vulnerabilities at the source level before any of that happens.

How it fits in

[Source code] → Guard CLI scan → [WASM build] → [Stellar deploy]

• Runs purely on Rust source — no Stellar SDK, no network connection, no wallet required.
• Exit code 1 on High findings lets CI block a deploy automatically.
• --json output can be piped into any dashboard or audit log.
• --sarif emits SARIF 2.1.0 for GitHub Advanced Security and other code scanning integrations.
• --output findings.json writes JSON output to disk for CI logs that should stay clean.

Deployment workflow

# 1. Scan before building — fails fast on High findings (exit 1)
cargo run -p soroban-guard-cli -- scan ./my-contract --json > findings.json

# 2. Build the WASM artifact only if scan passed
cargo build --target wasm32-unknown-unknown --release

# 3. Deploy to Stellar Testnet
stellar contract deploy \
  --wasm target/wasm32-unknown-unknown/release/my_contract.wasm \
  --source <account-name> \
  --network testnet

# 4. Or deploy to Mainnet
stellar contract deploy \
  --wasm target/wasm32-unknown-unknown/release/my_contract.wasm \
  --source <account-name> \
  --network mainnet

CI example (GitHub Actions)

- name: Guard CLI scan
  run: cargo run -p soroban-guard-cli -- scan ./my-contract --sarif --output findings.sarif
  # exits 1 on High findings — blocks the workflow

- name: Build WASM
  run: cargo build --target wasm32-unknown-unknown --release

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Workspace layout

Crate	Role
crates/cli	clap entrypoint, reporting
crates/analyzer	Walk .rs files, parse with syn, run checks
crates/checks	Check trait + individual detectors

See docs/checks.md for implemented rules, docs/json-schema.md for the --json output schema, docs/integrations.md for pre-commit / CI / editor snippets, and CONTRIBUTING.md to add a check.

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License

MIT OR Apache-2.0 (see workspace Cargo.toml).