Libafl

LibAFL

LibAFL is a modular fuzzing library that implements features from AFL-based fuzzers like AFL++. Unlike traditional fuzzers, LibAFL provides all functionality in a modular and customizable way as a Rust library. It can be used as a drop-in replacement for libFuzzer or as a library to build custom fuzzers from scratch.

When to Use

Fuzzer	Best For	Complexity
libFuzzer	Quick setup, single-threaded	Low
AFL++	Multi-core, general purpose	Medium
LibAFL	Custom fuzzers, advanced features, research	High

Choose LibAFL when:

• You need custom mutation strategies or feedback mechanisms
• Standard fuzzers don't support your target architecture
• You want to implement novel fuzzing techniques
• You need fine-grained control over fuzzing components
• You're conducting fuzzing research

Quick Start

LibAFL can be used as a drop-in replacement for libFuzzer with minimal setup:

extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
    // Call your code with fuzzer-provided data
    my_function(data, size);
    return 0;
}