# Slither, the Solidity source analyzer Logo [![Build Status](https://img.shields.io/github/workflow/status/crytic/slither/CI/master)](https://github.com/crytic/slither/actions?query=workflow%3ACI) [![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](#features) - [Bugs and Optimizations Detection](#bugs-and-optimizations-detection) - [Printers](#printers) - [Tools](#tools) - [How to Install](#how-to-install) ## 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 ## Bugs and Optimizations Detection 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 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-asm` | [Constant functions using assembly code](https://github.com/crytic/slither/wiki/Detector-Documentation#constant-functions-using-assembly-code) | Medium | Medium 15 | `constant-function-state` | [Constant functions changing the state](https://github.com/crytic/slither/wiki/Detector-Documentation#constant-functions-changing-the-state) | Medium | Medium 16 | `reentrancy-no-eth` | [Reentrancy vulnerabilities (no theft of ethers)](https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-1) | Medium | Medium 17 | `tx-origin` | [Dangerous usage of `tx.origin`](https://github.com/crytic/slither/wiki/Detector-Documentation#dangerous-usage-of-txorigin) | Medium | Medium 18 | `unchecked-lowlevel` | [Unchecked low-level calls](https://github.com/crytic/slither/wiki/Detector-Documentation#unchecked-low-level-calls) | Medium | Medium 19 | `unchecked-send` | [Unchecked send](https://github.com/crytic/slither/wiki/Detector-Documentation#unchecked-send) | Medium | Medium 20 | `uninitialized-local` | [Uninitialized local variables](https://github.com/crytic/slither/wiki/Detector-Documentation#uninitialized-local-variables) | Medium | Medium 21 | `unused-return` | [Unused return values](https://github.com/crytic/slither/wiki/Detector-Documentation#unused-return) | Medium | Medium 22 | `shadowing-builtin` | [Built-in symbol shadowing](https://github.com/crytic/slither/wiki/Detector-Documentation#builtin-symbol-shadowing) | Low | High 23 | `shadowing-local` | [Local variables shadowing](https://github.com/crytic/slither/wiki/Detector-Documentation#local-variable-shadowing) | Low | High 24 | `void-cst` | [Constructor called not implemented](https://github.com/crytic/slither/wiki/Detector-Documentation#void-constructor) | Low | High 25 | `calls-loop` | [Multiple calls in a loop](https://github.com/crytic/slither/wiki/Detector-Documentation/#calls-inside-a-loop) | Low | Medium 26 | `reentrancy-benign` | [Benign reentrancy vulnerabilities](https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-2) | Low | Medium 27 | `reentrancy-events` | [Reentrancy vulnerabilities leading to out-of-order Events](https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-3) | Low | Medium 28 | `timestamp` | [Dangerous usage of `block.timestamp`](https://github.com/crytic/slither/wiki/Detector-Documentation#block-timestamp) | Low | Medium 29 | `assembly` | [Assembly usage](https://github.com/crytic/slither/wiki/Detector-Documentation#assembly-usage) | Informational | High 30 | `deprecated-standards` | [Deprecated Solidity Standards](https://github.com/crytic/slither/wiki/Detector-Documentation#deprecated-standards) | Informational | High 31 | `erc20-indexed` | [Un-indexed ERC20 event parameters](https://github.com/crytic/slither/wiki/Detector-Documentation#unindexed-erc20-event-parameters) | Informational | High 32 | `low-level-calls` | [Low level calls](https://github.com/crytic/slither/wiki/Detector-Documentation#low-level-calls) | Informational | High 33 | `naming-convention` | [Conformance to Solidity naming conventions](https://github.com/crytic/slither/wiki/Detector-Documentation#conformance-to-solidity-naming-conventions) | Informational | High 34 | `pragma` | [If different pragma directives are used](https://github.com/crytic/slither/wiki/Detector-Documentation#different-pragma-directives-are-used) | Informational | High 35 | `solc-version` | [Incorrect Solidity version](https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-versions-of-solidity) | Informational | High 36 | `unused-state` | [Unused state variables](https://github.com/crytic/slither/wiki/Detector-Documentation#unused-state-variables) | Informational | High 37 | `reentrancy-unlimited-gas` | [Reentrancy vulnerabilities through send and transfer](https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-4) | Informational | Medium 38 | `too-many-digits` | [Conformance to numeric notation best practices](https://github.com/crytic/slither/wiki/Detector-Documentation#too-many-digits) | Informational | Medium 39 | `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 40 | `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 See the [Detectors Documentation](https://github.com/crytic/slither/wiki/Detector-Documentation) for more information. By default, all the detectors are run. Check out [Crytic](https://crytic.io/) to get access to additional Slither's detectors and GitHub integration. ## Printers ### Quick Review Printers - `human-summary`: [Print a human-readable summary of the contracts](https://github.com/trailofbits/slither/wiki/Printer-documentation#human-summary) - `inheritance-graph`: [Export the inheritance graph of each contract to a dot file](https://github.com/trailofbits/slither/wiki/Printer-documentation#inheritance-graph) - `contract-summary`: [Print a summary of the contracts](https://github.com/trailofbits/slither/wiki/Printer-documentation#contract-summary) ### In-Depth Review Printers - `call-graph`: [Export the call-graph of the contracts to a dot file](https://github.com/trailofbits/slither/wiki/Printer-documentation#call-graph) - `cfg`: [Export the CFG of each functions](https://github.com/trailofbits/slither/wiki/Printer-documentation#cfg) - `function-summary`: [Print a summary of the functions](https://github.com/trailofbits/slither/wiki/Printer-documentation#function-summary) - `vars-and-auth`: [Print the state variables written and the authorization of the functions](https://github.com/crytic/slither/wiki/Printer-documentation#variables-written-and-authorization) To run a printer, use `--print` and a comma-separated list of printers. See the [Printer documentation](https://github.com/crytic/slither/wiki/Printer-documentation) for the complete lists. ## Tools - `slither-check-upgradeability`: [Review `delegatecall`-based upgradeability](https://github.com/crytic/slither/wiki/Upgradeability-Checks) - `slither-flat`: [Flatten a codebase](https://github.com/crytic/slither/wiki/Contract-Flattening) - `slither-erc`: [Check the ERC's conformance](https://github.com/crytic/slither/wiki/ERC-Conformance) - `slither-format`: [Automatic patches generation](https://github.com/crytic/slither/wiki/Slither-format) See the [Tool documentation](https://github.com/crytic/slither/wiki/Tool-Documentation) for additional tools. [Contact us](https://www.trailofbits.com/contact/) to get help on building custom tools. ## How to install Slither requires Python 3.6+ and [solc](https://github.com/ethereum/solidity/), the Solidity compiler. ### Using Pip ``` $ pip3 install slither-analyzer ``` ### Using Git ```bash $ git clone https://github.com/crytic/slither.git && cd slither $ python3 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. ``` 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. ## Publication - [Slither: A Static Analysis Framework For Smart Contracts](https://arxiv.org/abs/1908.09878), Josselin Feist, Gustavo Grieco, Alex Groce - WETSEB '19 If you are using Slither on an academic work, consider applying to the [Crytic $10k Research Prize](https://blog.trailofbits.com/2019/11/13/announcing-the-crytic-10k-research-prize/).