American fuzzy lop is a security-oriented fuzzer that employs a novel type
of compile-time instrumentation and genetic algorithms to automatically
discover clean, interesting test cases that trigger new internal states in
the targeted binary. This substantially improves the functional coverage
for the fuzzed code. The compact synthesized corpora produced by the tool
are also useful for seeding other, more labor- or resource-intensive
testing regimes down the road.
Compared to other instrumented fuzzers, afl-fuzz is designed to be
practical: it has modest performance overhead, uses a variety of highly
effective fuzzing strategies and effort minimization tricks, requires
essentially no configuration, and seamlessly handles complex, real-world
use cases - say, common image parsing or file compression libraries.