Slither, the Solidity source 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) 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 documentation.
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 | High | High |
| 2 | shadowing-state |
State variables shadowing | High | High |
| 3 | suicidal |
Functions allowing anyone to destruct the contract | High | High |
| 4 | uninitialized-state |
Uninitialized state variables | High | High |
| 5 | uninitialized-storage |
Uninitialized storage variables | High | High |
| 6 | arbitrary-send |
Functions that send ether to arbitrary destinations | High | Medium |
| 7 | controlled-delegatecall |
Controlled delegatecall destination | High | Medium |
| 8 | reentrancy-eth |
Reentrancy vulnerabilities (theft of ethers) | High | Medium |
| 9 | erc20-interface |
Incorrect ERC20 interfaces | Medium | High |
| 10 | erc721-interface |
Incorrect ERC721 interfaces | Medium | High |
| 11 | incorrect-equality |
Dangerous strict equalities | Medium | High |
| 12 | locked-ether |
Contracts that lock ether | Medium | High |
| 13 | shadowing-abstract |
State variables shadowing from abstract contracts | Medium | High |
| 14 | constant-function |
Constant functions changing the state | Medium | Medium |
| 15 | reentrancy-no-eth |
Reentrancy vulnerabilities (no theft of ethers) | Medium | Medium |
| 16 | tx-origin |
Dangerous usage of tx.origin |
Medium | Medium |
| 17 | unchecked-lowlevel |
Unchecked low-level calls | Medium | Medium |
| 18 | unchecked-send |
Unchecked send | Medium | Medium |
| 19 | uninitialized-local |
Uninitialized local variables | Medium | Medium |
| 20 | unused-return |
Unused return values | Medium | Medium |
| 21 | shadowing-builtin |
Built-in symbol shadowing | Low | High |
| 22 | shadowing-local |
Local variables shadowing | Low | High |
| 23 | calls-loop |
Multiple calls in a loop | Low | Medium |
| 24 | reentrancy-benign |
Benign reentrancy vulnerabilities | Low | Medium |
| 25 | timestamp |
Dangerous usage of block.timestamp |
Low | Medium |
| 26 | assembly |
Assembly usage | Informational | High |
| 27 | deprecated-standards |
Deprecated Solidity Standards | Informational | High |
| 28 | erc20-indexed |
Un-indexed ERC20 event parameters | Informational | High |
| 29 | low-level-calls |
Low level calls | Informational | High |
| 30 | naming-convention |
Conformance to Solidity naming conventions | Informational | High |
| 31 | pragma |
If different pragma directives are used | Informational | High |
| 32 | solc-version |
Incorrect Solidity version (< 0.4.24 or complex pragma) | Informational | High |
| 33 | unused-state |
Unused state variables | Informational | High |
| 34 | too-many-digits |
Conformance to numeric notation best practices | Informational | Medium |
| 35 | constable-states |
State variables that could be declared constant | Optimization | High |
| 36 | external-function |
Public function that could be declared as external | Optimization | High |
Contact us 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 |
| 2 | cfg |
Export the CFG of each functions |
| 3 | contract-summary |
Print a summary of the contracts |
| 4 | data-dependency |
Print the data dependencies of the variables |
| 5 | function-id |
Print the keccack256 signature of the functions |
| 6 | function-summary |
Print a summary of the functions |
| 7 | human-summary |
Print a human-readable summary of the contracts |
| 8 | inheritance |
Print the inheritance relations between contracts |
| 9 | inheritance-graph |
Export the inheritance graph of each contract to a dot file |
| 10 | modifiers |
Print the modifiers called by each function |
| 11 | require |
Print the require and assert calls of each function |
| 12 | slithir |
Print the slithIR representation of the functions |
| 13 | slithir-ssa |
Print the slithIR representation of the functions |
| 14 | variable-order |
Print the storage order of the state variables |
| 15 | vars-and-auth |
Print the state variables written and the authorization of the functions |
How to install
Slither requires Python 3.6+ and solc, the Solidity compiler.
Using Pip
$ pip install slither-analyzer
Using Git
$ git clone https://github.com/trailofbits/slither.git && cd slither
$ python setup.py install We recommend using an Python virtual environment, as detailed in the Developer Installation Instructions, if you prefer to install Slither via git.
Using Docker
Use the 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 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 (#ethereum) for help using or extending Slither.
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The Printer documentation describes the information Slither is capable of visualizing for each contract.
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The Detector documentation describes how to write a new vulnerability analyses.
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The API documentation describes the methods and objects available for custom analyses.
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The SlithIR documentation describes the SlithIR intermediate representation.
License
Slither is licensed and distributed under the AGPLv3 license. Contact us if you're looking for an exception to the terms.