atherislisted
Install: claude install-skill kevinvwong/stack-agents
# Atheris
Atheris is a coverage-guided Python fuzzer built on libFuzzer. It enables fuzzing of both pure Python code and Python C extensions with integrated AddressSanitizer support for detecting memory corruption issues.
## When to Use
| Fuzzer | Best For | Complexity |
|--------|----------|------------|
| Atheris | Python code and C extensions | Low-Medium |
| Hypothesis | Property-based testing | Low |
| python-afl | AFL-style fuzzing | Medium |
**Choose Atheris when:**
- Fuzzing pure Python code with coverage guidance
- Testing Python C extensions for memory corruption
- Integration with libFuzzer ecosystem is desired
- AddressSanitizer support is needed
## Quick Start
```python
import sys
import atheris
@atheris.instrument_func
def test_one_input(data: bytes):
if len(data) == 4:
if data[0] == 0x46: # "F"
if data[1] == 0x55: # "U"
if data[2] == 0x5A: # "Z"
if data[3] == 0x5A: # "Z"
raise RuntimeError("You caught me")
def main():
atheris.Setup(sys.argv, test_one_input)
atheris.Fuzz()
if __name__ == "__main__":
main()
```
Run:
```bash
python fuzz.py
```
## Installation
Atheris supports 32-bit and 64-bit Linux, and macOS. We recommend fuzzing on Linux because it's simpler to manage and often faster.
### Prerequisites
- Python 3.7 or later
- Recent version of clang (preferably [latest release](https://github.com/llvm/llvm-project/releases))
- For Docker users: [Do