| ===================== |
| AFL quick start guide |
| ===================== |
| |
| You should read docs/README. It's pretty short. If you really can't, here's |
| how to hit the ground running: |
| |
| 1) Compile AFL with 'make'. If build fails, see docs/INSTALL for tips. |
| |
| 2) Find or write a reasonably fast and simple program that takes data from |
| a file or stdin, processes it in a test-worthy way, then exits cleanly. |
| If testing a network service, modify it to run in the foreground and read |
| from stdin. When fuzzing a format that uses checksums, comment out the |
| checksum verification code, too. |
| |
| The program must crash properly when a fault is encountered. Watch out for |
| custom SIGSEGV or SIGABRT handlers and background processes. For tips on |
| detecting non-crashing flaws, see section 11 in docs/README. |
| |
| 3) Compile the program / library to be fuzzed using afl-gcc. A common way to |
| do this would be: |
| |
| CC=/path/to/afl-gcc CXX=/path/to/afl-g++ ./configure --disable-shared |
| make clean all |
| |
| If program build fails, ping <afl-users@googlegroups.com>. |
| |
| 4) Get a small but valid input file that makes sense to the program. When |
| fuzzing verbose syntax (SQL, HTTP, etc), create a dictionary as described in |
| dictionaries/README.dictionaries, too. |
| |
| 5) If the program reads from stdin, run 'afl-fuzz' like so: |
| |
| ./afl-fuzz -i testcase_dir -o findings_dir -- \ |
| /path/to/tested/program [...program's cmdline...] |
| |
| If the program takes input from a file, you can put @@ in the program's |
| command line; AFL will put an auto-generated file name in there for you. |
| |
| 6) Investigate anything shown in red in the fuzzer UI by promptly consulting |
| docs/status_screen.txt. |
| |
| That's it. Sit back, relax, and - time permitting - try to skim through the |
| following files: |
| |
| - docs/README - A general introduction to AFL, |
| - docs/perf_tips.txt - Simple tips on how to fuzz more quickly, |
| - docs/status_screen.txt - An explanation of the tidbits shown in the UI, |
| - docs/parallel_fuzzing.txt - Advice on running AFL on multiple cores. |