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A vulnerable C program for testing fuzzers.
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Welcome to Fuzzgoat

This C program has been deliberately backdoored with several memory corruption bugs to test the efficacy of fuzzers and other analysis tools. Each vulnerability is clearly commented in fuzzgoat.c. Under input-files/ are files to trigger each vulnerability.

CAUTION: Do not copy any of this code - there is evil stuff in this repo.

Install AFL (American Fuzzy Lop)

While Fuzzgoat can be attacked using any fuzzer, we like AFL. To install it:

  1. Download AFL:

  2. Build AFL with make install

  3. See the AFL quick start guide for more info:

Building Fuzzgoat

Fuzzgoat builds with make. With afl-gcc in your PATH:


Running AFL

With afl-fuzz in your PATH and a seed file in a directory called in/

afl-fuzz -i in -o out ./fuzzgoat @@

or simply:

make afl

Thank You

Contributor: Joseph Carlos

Fuzzgoat was adapted from udp/json-parser - we chose it because:

  • Its not too big or cumbersome - ~1200 lines of C yet lots of paths for a fuzzer to dig into.
  • Performance: its very fast at ~1500 execs per sec per core.
  • The code is clean and very readable.

Fuzz Stati0n would like to thank the creators and maintainers of udp/json-parser.

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