Fuzzable – Framework For Automating Fuzzable Target Discovery With Static Analysis

Framework for Automating Fuzzable Target Discovery with Static Analysis.

Some binary targets may require some sanitizing (ie. signature matching, or identifying functions from inlining), and therefore fuzzable primarily uses Binary Ninja as a disassembly backend because of it’s ability to effectively solve these problems. Therefore, it can be utilized both as a standalone tool and plugin.

If you have Binary Ninja Commercial, be sure to install the API for standalone headless usage:

Install with pip:

To install manually:

You can now analyze binaries and/or source code with the tool!

fuzzable can be easily installed through the Binary Ninja plugin marketplace by going to Binary Ninja > Manage Plugins and searching for it. Here is an example of the fuzzable plugin running, accuracy identifying targets for fuzzing and further vulnerability assessment:

fuzzable comes with various options to help better tune your analysis. More will be supported in future plans and any feature requests made.

Every targets you want to analyze is diverse, and fuzzable will not be able to account for every edge case behavior in the program target. Thus, it may be important during analysis to tune these weights appropriately to see if different results make more sense for your use case. To tune these weights in the CLI, simply specify the --score-weights argument:

By default, fuzzable will filter out function targets based on the following criteria:

To see calls that got filtered out by fuzzable, set the --list_ignored flag:

In Binary Ninja, you can turn this setting in Settings > Fuzzable > List Ignored Calls.

In the case that fuzzable falsely filters out important calls that should be analyzed, it is recommended to use --include-* arguments to include them during the run:

In Binary Ninja, this is supported through Settings > Fuzzable > Include non-top level calls and Symbols to Exclude.

Now that you have found your ideal candidates to fuzz, fuzzable will also help you generate fuzzing harnesses that are (almost) ready to instrument and compile for use with either a file-based fuzzer (ie. AFL++, Honggfuzz) or in-memory fuzzer (libFuzzer). To do so in the CLI:

At the moment, this feature is quite rudimentary, as it simply will create a standalone C++ harness populated with the appropriate parameters, and will not auto-generate code that is needed for any runtime behaviors (ie. instantiating and freeing structures). However, the templates created for fuzzable should get still get you running quickly. Here are some ambitious features I would like to implement down the road:

In the CLI, simply pass the --export argument with a filename with the appropriate extension:

In Binary Ninja, go to Plugins > Fuzzable > Export Fuzzability Report > ... and select the format you want to export to and the path you want to write it to.

This tool will be continuously developed, and any help from external mantainers are appreciated!



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