slither/README.md

# Slither, the Solidity source analyzer
<img src="./logo.png" alt="Logo" width="500"/>

[![Build Status](https://travis-ci.com/crytic/slither.svg?token=JEF97dFy1QsDCfQ2Wusd&branch=master)](https://travis-ci.com/crytic/slither)
[![Slack Status](https://empireslacking.herokuapp.com/badge.svg)](https://empireslacking.herokuapp.com)
[![PyPI version](https://badge.fury.io/py/slither-analyzer.svg)](https://badge.fury.io/py/slither-analyzer)

Slither is a Solidity static analysis framework written in Python 3. It runs a suite of vulnerability detectors, prints visual information about contract details, and provides an API to easily write custom analyses. Slither enables developers to find vulnerabilities, enhance their code comprehension, and quickly prototype custom analyses.

## Features

* Detects vulnerable Solidity code with low false positives
* Identifies where the error condition occurs in the source code
* Easily integrates into continuous integration and Truffle builds
* Built-in 'printers' quickly report crucial contract information
* Detector API to write custom analyses in Python
* Ability to analyze contracts written with Solidity >= 0.4
* Intermediate representation ([SlithIR](https://github.com/trailofbits/slither/wiki/SlithIR)) enables simple, high-precision analyses
* Correctly parses 99.9% of all public Solidity code
* Average execution time of less than 1 second per contract

## Usage

Run Slither on a Truffle/Embark/Dapp/Etherlime application:
```
slither .
```

Run Slither on a single file:
``` 
$ slither tests/uninitialized.sol 
``` 

For additional configuration, see the [usage](https://github.com/trailofbits/slither/wiki/Usage) documentation. 

Use [solc-select](https://github.com/crytic/solc-select) if your contracts require older versions of solc.

## Detectors

By default, all the detectors are run.

Num | Detector | What it Detects | Impact | Confidence
--- | --- | --- | --- | ---
1 | `rtlo` | [Right-To-Left-Override control character is used](https://github.com/crytic/slither/wiki/Detector-Documentation#right-to-left-override-character) | High | High
2 | `shadowing-state` | [State variables shadowing](https://github.com/crytic/slither/wiki/Detector-Documentation#state-variable-shadowing) | High | High
3 | `suicidal` | [Functions allowing anyone to destruct the contract](https://github.com/crytic/slither/wiki/Detector-Documentation#suicidal) | High | High
4 | `uninitialized-state` | [Uninitialized state variables](https://github.com/crytic/slither/wiki/Detector-Documentation#uninitialized-state-variables) | High | High
5 | `uninitialized-storage` | [Uninitialized storage variables](https://github.com/crytic/slither/wiki/Detector-Documentation#uninitialized-storage-variables) | High | High
6 | `arbitrary-send` | [Functions that send ether to arbitrary destinations](https://github.com/crytic/slither/wiki/Detector-Documentation#functions-that-send-ether-to-arbitrary-destinations) | High | Medium
7 | `controlled-delegatecall` | [Controlled delegatecall destination](https://github.com/crytic/slither/wiki/Detector-Documentation#controlled-delegatecall) | High | Medium
8 | `reentrancy-eth` | [Reentrancy vulnerabilities (theft of ethers)](https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities) | High | Medium
9 | `erc20-interface` | [Incorrect ERC20 interfaces](https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-erc20-interface) | Medium | High
10 | `erc721-interface` | [Incorrect ERC721 interfaces](https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-erc721-interface) | Medium | High
11 | `incorrect-equality` | [Dangerous strict equalities](https://github.com/crytic/slither/wiki/Detector-Documentation#dangerous-strict-equalities) | Medium | High
12 | `locked-ether` | [Contracts that lock ether](https://github.com/crytic/slither/wiki/Detector-Documentation#contracts-that-lock-ether) | Medium | High
13 | `shadowing-abstract` | [State variables shadowing from abstract contracts](https://github.com/crytic/slither/wiki/Detector-Documentation#state-variable-shadowing-from-abstract-contracts) | Medium | High
14 | `constant-function` | [Constant functions changing the state](https://github.com/crytic/slither/wiki/Detector-Documentation#constant-functions-changing-the-state) | Medium | Medium
15 | `reentrancy-no-eth` | [Reentrancy vulnerabilities (no theft of ethers)](https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-1) | Medium | Medium
16 | `tx-origin` | [Dangerous usage of `tx.origin`](https://github.com/crytic/slither/wiki/Detector-Documentation#dangerous-usage-of-txorigin) | Medium | Medium
17 | `unchecked-lowlevel` | [Unchecked low-level calls](https://github.com/crytic/slither/wiki/Detector-Documentation#unchecked-low-level-calls) | Medium | Medium
18 | `unchecked-send` | [Unchecked send](https://github.com/crytic/slither/wiki/Detector-Documentation#unchecked-send) | Medium | Medium
19 | `uninitialized-local` | [Uninitialized local variables](https://github.com/crytic/slither/wiki/Detector-Documentation#uninitialized-local-variables) | Medium | Medium
20 | `unused-return` | [Unused return values](https://github.com/crytic/slither/wiki/Detector-Documentation#unused-return) | Medium | Medium
21 | `shadowing-builtin` | [Built-in symbol shadowing](https://github.com/crytic/slither/wiki/Detector-Documentation#builtin-symbol-shadowing) | Low | High
22 | `shadowing-local` | [Local variables shadowing](https://github.com/crytic/slither/wiki/Detector-Documentation#local-variable-shadowing) | Low | High
23 | `void-cst` | [Constructor called not implemented](https://github.com/crytic/slither/wiki/Detector-Documentation#void-constructor) | Low | High
24 | `calls-loop` | [Multiple calls in a loop](https://github.com/crytic/slither/wiki/Detector-Documentation/_edit#calls-inside-a-loop) | Low | Medium
25 | `reentrancy-benign` | [Benign reentrancy vulnerabilities](https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-2) | Low | Medium
26 | `timestamp` | [Dangerous usage of `block.timestamp`](https://github.com/crytic/slither/wiki/Detector-Documentation#block-timestamp) | Low | Medium
27 | `assembly` | [Assembly usage](https://github.com/crytic/slither/wiki/Detector-Documentation#assembly-usage) | Informational | High
28 | `deprecated-standards` | [Deprecated Solidity Standards](https://github.com/crytic/slither/wiki/Detector-Documentation#deprecated-standards) | Informational | High
29 | `erc20-indexed` | [Un-indexed ERC20 event parameters](https://github.com/crytic/slither/wiki/Detector-Documentation#unindexed-erc20-event-parameters) | Informational | High
30 | `low-level-calls` | [Low level calls](https://github.com/crytic/slither/wiki/Detector-Documentation#low-level-calls) | Informational | High
31 | `naming-convention` | [Conformance to Solidity naming conventions](https://github.com/crytic/slither/wiki/Detector-Documentation#conformance-to-solidity-naming-conventions) | Informational | High
32 | `pragma` | [If different pragma directives are used](https://github.com/crytic/slither/wiki/Detector-Documentation#different-pragma-directives-are-used) | Informational | High
33 | `solc-version` | [Incorrect Solidity version (< 0.4.24 or complex pragma)](https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-versions-of-solidity) | Informational | High
34 | `unused-state` | [Unused state variables](https://github.com/crytic/slither/wiki/Detector-Documentation#unused-state-variables) | Informational | High
35 | `too-many-digits` | [Conformance to numeric notation best practices](https://github.com/crytic/slither/wiki/Detector-Documentation#too-many-digits) | Informational | Medium
36 | `constable-states` | [State variables that could be declared constant](https://github.com/crytic/slither/wiki/Detector-Documentation#state-variables-that-could-be-declared-constant) | Optimization | High
37 | `external-function` | [Public function that could be declared as external](https://github.com/crytic/slither/wiki/Detector-Documentation#public-function-that-could-be-declared-as-external) | Optimization | High


[Contact us](https://www.trailofbits.com/contact/) to get access to additional detectors.

### Printers

To run a printer, use `--print` and a comma-separated list of printers.

Num | Printer | Description
--- | --- | ---
1 | `call-graph` | [Export the call-graph of the contracts to a dot file](https://github.com/trailofbits/slither/wiki/Printer-documentation#call-graph)
2 | `cfg` | [Export the CFG of each functions](https://github.com/trailofbits/slither/wiki/Printer-documentation#cfg)
3 | `contract-summary` | [Print a summary of the contracts](https://github.com/trailofbits/slither/wiki/Printer-documentation#contract-summary)
4 | `data-dependency` | [Print the data dependencies of the variables](https://github.com/trailofbits/slither/wiki/Printer-documentation#data-dependencies)
5 | `function-id` | [Print the keccack256 signature of the functions](https://github.com/trailofbits/slither/wiki/Printer-documentation#function-id)
6 | `function-summary` | [Print a summary of the functions](https://github.com/trailofbits/slither/wiki/Printer-documentation#function-summary)
7 | `human-summary` | [Print a human-readable summary of the contracts](https://github.com/trailofbits/slither/wiki/Printer-documentation#human-summary)
8 | `inheritance` | [Print the inheritance relations between contracts](https://github.com/trailofbits/slither/wiki/Printer-documentation#inheritance)
9 | `inheritance-graph` | [Export the inheritance graph of each contract to a dot file](https://github.com/trailofbits/slither/wiki/Printer-documentation#inheritance-graph)
10 | `modifiers` | [Print the modifiers called by each function](https://github.com/trailofbits/slither/wiki/Printer-documentation#modifiers)
11 | `require` | [Print the require and assert calls of each function](https://github.com/trailofbits/slither/wiki/Printer-documentation#require)
12 | `slithir` | [Print the slithIR representation of the functions](https://github.com/trailofbits/slither/wiki/Printer-documentation#slithir)
13 | `slithir-ssa` | [Print the slithIR representation of the functions](https://github.com/trailofbits/slither/wiki/Printer-documentation#slithir-ssa)
14 | `variable-order` | [Print the storage order of the state variables](https://github.com/trailofbits/slither/wiki/Printer-documentation#variable-order)
15 | `vars-and-auth` | [Print the state variables written and the authorization of the functions](https://github.com/trailofbits/slither/wiki/Printer-documentation#variables-written-and-authorization)

## How to install

Slither requires Python 3.6+ and [solc](https://github.com/ethereum/solidity/), the Solidity compiler. 

### Using Pip

```
$ pip install slither-analyzer
```

### Using Git

```bash
$ git clone https://github.com/crytic/slither.git && cd slither
$ python setup.py install 
```

We recommend using an Python virtual environment, as detailed in the [Developer Installation Instructions](https://github.com/trailofbits/slither/wiki/Developer-installation), if you prefer to install Slither via git.

### Using Docker

Use the [`eth-security-toolbox`](https://github.com/trailofbits/eth-security-toolbox/) docker image. It includes all of our security tools and every major version of Solidity in a single image. `/home/share` will be mounted to `/share`  in the container. Use [`solc-select`](https://github.com/trailofbits/eth-security-toolbox/#usage) to switch the Solidity version.

```
docker pull trailofbits/eth-security-toolbox
```

To share a directory in the container:

```
docker run -it -v /home/share:/share trailofbits/eth-security-toolbox
```

## Getting Help

Feel free to stop by our [Slack channel](https://empireslacking.herokuapp.com) (#ethereum) for help using or extending Slither.

* The [Printer documentation](https://github.com/trailofbits/slither/wiki/Printer-documentation) describes the information Slither is capable of visualizing for each contract.

* The [Detector documentation](https://github.com/trailofbits/slither/wiki/Adding-a-new-detector) describes how to write a new vulnerability analyses.

* The [API documentation](https://github.com/trailofbits/slither/wiki/API-examples) describes the methods and objects available for custom analyses.

* The [SlithIR documentation](https://github.com/trailofbits/slither/wiki/SlithIR) describes the SlithIR intermediate representation.

## License

Slither is licensed and distributed under the AGPLv3 license. [Contact us](mailto:opensource@trailofbits.com) if you're looking for an exception to the terms.