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.
- Detects vulnerable Solidity code with low false positives (see the list of trophies)
- 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
Run Slither on a Truffle/Embark/Dapp/Etherlime/Hardhat application:
slither .Run Slither on a single file:
slither tests/uninitialized.solFor GitHub action integration, see slither-action. For additional configuration, see the usage documentation.
Use solc-select if your contracts require older versions of solc.
| Num | Detector | What it Detects | Impact | Confidence |
|---|---|---|---|---|
| 1 | abiencoderv2-array |
Storage abiencoderv2 array | High | High |
| 2 | array-by-reference |
Modifying storage array by value | High | High |
| 3 | incorrect-shift |
The order of parameters in a shift instruction is incorrect. | High | High |
| 4 | multiple-constructors |
Multiple constructor schemes | High | High |
| 5 | name-reused |
Contract's name reused | High | High |
| 6 | public-mappings-nested |
Public mappings with nested variables | High | High |
| 7 | rtlo |
Right-To-Left-Override control character is used | High | High |
| 8 | shadowing-state |
State variables shadowing | High | High |
| 9 | suicidal |
Functions allowing anyone to destruct the contract | High | High |
| 10 | uninitialized-state |
Uninitialized state variables | High | High |
| 11 | uninitialized-storage |
Uninitialized storage variables | High | High |
| 12 | unprotected-upgrade |
Unprotected upgradeable contract | High | High |
| 13 | arbitrary-send |
Functions that send Ether to arbitrary destinations | High | Medium |
| 14 | controlled-array-length |
Tainted array length assignment | High | Medium |
| 15 | controlled-delegatecall |
Controlled delegatecall destination | High | Medium |
| 16 | delegatecall-loop |
Payable functions using delegatecall inside a loop |
High | Medium |
| 17 | msg-value-loop |
msg.value inside a loop | High | Medium |
| 18 | reentrancy-eth |
Reentrancy vulnerabilities (theft of ethers) | High | Medium |
| 19 | storage-array |
Signed storage integer array compiler bug | High | Medium |
| 20 | unchecked-transfer |
Unchecked tokens transfer | High | Medium |
| 21 | weak-prng |
Weak PRNG | High | Medium |
| 22 | enum-conversion |
Detect dangerous enum conversion | Medium | High |
| 23 | erc20-interface |
Incorrect ERC20 interfaces | Medium | High |
| 24 | erc721-interface |
Incorrect ERC721 interfaces | Medium | High |
| 25 | incorrect-equality |
Dangerous strict equalities | Medium | High |
| 26 | locked-ether |
Contracts that lock ether | Medium | High |
| 27 | mapping-deletion |
Deletion on mapping containing a structure | Medium | High |
| 28 | shadowing-abstract |
State variables shadowing from abstract contracts | Medium | High |
| 29 | tautology |
Tautology or contradiction | Medium | High |
| 30 | write-after-write |
Unused write | Medium | High |
| 31 | boolean-cst |
Misuse of Boolean constant | Medium | Medium |
| 32 | constant-function-asm |
Constant functions using assembly code | Medium | Medium |
| 33 | constant-function-state |
Constant functions changing the state | Medium | Medium |
| 34 | divide-before-multiply |
Imprecise arithmetic operations order | Medium | Medium |
| 35 | reentrancy-no-eth |
Reentrancy vulnerabilities (no theft of ethers) | Medium | Medium |
| 36 | reused-constructor |
Reused base constructor | Medium | Medium |
| 37 | tx-origin |
Dangerous usage of tx.origin |
Medium | Medium |
| 38 | unchecked-lowlevel |
Unchecked low-level calls | Medium | Medium |
| 39 | unchecked-send |
Unchecked send | Medium | Medium |
| 40 | uninitialized-local |
Uninitialized local variables | Medium | Medium |
| 41 | unused-return |
Unused return values | Medium | Medium |
| 42 | incorrect-modifier |
Modifiers that can return the default value | Low | High |
| 43 | shadowing-builtin |
Built-in symbol shadowing | Low | High |
| 44 | shadowing-local |
Local variables shadowing | Low | High |
| 45 | uninitialized-fptr-cst |
Uninitialized function pointer calls in constructors | Low | High |
| 46 | variable-scope |
Local variables used prior their declaration | Low | High |
| 47 | void-cst |
Constructor called not implemented | Low | High |
| 48 | calls-loop |
Multiple calls in a loop | Low | Medium |
| 49 | events-access |
Missing Events Access Control | Low | Medium |
| 50 | events-maths |
Missing Events Arithmetic | Low | Medium |
| 51 | incorrect-unary |
Dangerous unary expressions | Low | Medium |
| 52 | missing-zero-check |
Missing Zero Address Validation | Low | Medium |
| 53 | reentrancy-benign |
Benign reentrancy vulnerabilities | Low | Medium |
| 54 | reentrancy-events |
Reentrancy vulnerabilities leading to out-of-order Events | Low | Medium |
| 55 | timestamp |
Dangerous usage of block.timestamp |
Low | Medium |
| 56 | assembly |
Assembly usage | Informational | High |
| 57 | assert-state-change |
Assert state change | Informational | High |
| 58 | boolean-equal |
Comparison to boolean constant | Informational | High |
| 59 | deprecated-standards |
Deprecated Solidity Standards | Informational | High |
| 60 | erc20-indexed |
Un-indexed ERC20 event parameters | Informational | High |
| 61 | function-init-state |
Function initializing state variables | Informational | High |
| 62 | low-level-calls |
Low level calls | Informational | High |
| 63 | missing-inheritance |
Missing inheritance | Informational | High |
| 64 | naming-convention |
Conformity to Solidity naming conventions | Informational | High |
| 65 | pragma |
If different pragma directives are used | Informational | High |
| 66 | redundant-statements |
Redundant statements | Informational | High |
| 67 | solc-version |
Incorrect Solidity version | Informational | High |
| 68 | unimplemented-functions |
Unimplemented functions | Informational | High |
| 69 | unused-state |
Unused state variables | Informational | High |
| 70 | costly-loop |
Costly operations in a loop | Informational | Medium |
| 71 | dead-code |
Functions that are not used | Informational | Medium |
| 72 | reentrancy-unlimited-gas |
Reentrancy vulnerabilities through send and transfer | Informational | Medium |
| 73 | similar-names |
Variable names are too similar | Informational | Medium |
| 74 | too-many-digits |
Conformance to numeric notation best practices | Informational | Medium |
| 75 | constable-states |
State variables that could be declared constant | Optimization | High |
| 76 | external-function |
Public function that could be declared external | Optimization | High |
For more information, see
- The Detector Documentation for details on each detector
- The Detection Selection to run only selected detectors. By default, all the detectors are run.
- The Triage Mode to filter individual results
human-summary: Print a human-readable summary of the contractsinheritance-graph: Export the inheritance graph of each contract to a dot filecontract-summary: Print a summary of the contracts
call-graph: Export the call-graph of the contracts to a dot filecfg: Export the CFG of each functionsfunction-summary: Print a summary of the functionsvars-and-auth: Print the state variables written and the authorization of the functions
To run a printer, use --print and a comma-separated list of printers.
See the Printer documentation for the complete lists.
slither-check-upgradeability: Reviewdelegatecall-based upgradeabilityslither-prop: Automatic unit test and property generationslither-flat: Flatten a codebaseslither-check-erc: Check the ERC's conformanceslither-format: Automatic patch generation
See the Tool documentation for additional tools.
Contact us to get help on building custom tools.
Slither requires Python 3.6+ and solc, the Solidity compiler.
pip3 install slither-analyzergit clone https://github.com/crytic/slither.git && cd slither
python3 setup.py installWe recommend using a Python virtual environment, as detailed in the Developer Installation Instructions, if you prefer to install Slither via git.
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.
docker pull trailofbits/eth-security-toolboxTo share a directory in the container:
docker run -it -v /home/share:/share trailofbits/eth-security-toolboxFeel 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.
Slither is licensed and distributed under the AGPLv3 license. Contact us if you're looking for an exception to the terms.
- Slither: A Static Analysis Framework For Smart Contracts, Josselin Feist, Gustavo Grieco, Alex Groce - WETSEB '19
| Title | Usage | Authors | Venue |
|---|---|---|---|
| ReJection: A AST-Based Reentrancy Vulnerability Detection Method | AST-based analysis built on top of Slither | Rui Ma, Zefeng Jian, Guangyuan Chen, Ke Ma, Yujia Chen | CTCIS 19 |
| MPro: Combining Static and Symbolic Analysis forScalable Testing of Smart Contract | Leverage data dependency through Slither | William Zhang, Sebastian Banescu, Leodardo Pasos, Steven Stewart, Vijay Ganesh | ISSRE 2019 |
| ETHPLOIT: From Fuzzing to Efficient Exploit Generation against Smart Contracts | Leverage data dependency through Slither | Qingzhao Zhang, Yizhuo Wang, Juanru Li, Siqi Ma | SANER 20 |
| Verification of Ethereum Smart Contracts: A Model Checking Approach | Symbolic execution built on top of Slither’s CFG | Tam Bang, Hoang H Nguyen, Dung Nguyen, Toan Trieu, Tho Quan | IJMLC 20 |
| Smart Contract Repair | Rely on Slither’s vulnerabilities detectors | Xiao Liang Yu, Omar Al-Bataineh, David Lo, Abhik Roychoudhury | TOSEM 20 |
| Demystifying Loops in Smart Contracts | Leverage data dependency through Slither | Ben Mariano, Yanju Chen, Yu Feng, Shuvendu Lahiri, Isil Dillig | ASE 20 |
| Trace-Based Dynamic Gas Estimation of Loops in Smart Contracts | Use Slither’s CFG to detect loops | Chunmiao Li, Shijie Nie, Yang Cao, Yijun Yu, Zhenjiang Hu | IEEE Open J. Comput. Soc. 1 (2020) |
If you are using Slither on an academic work, consider applying to the Crytic $10k Research Prize.