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DARPA Challenge Binaries on Linux and OS X

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The DARPA Challenge Binaries (CBs) are custom-made programs specifically designed to contain vulnerabilities that represent a wide variety of crashing software flaws. They are more than simple test cases, they approximate real software with enough complexity to stress both manual and automated vulnerability discovery. The CBs come with extensive functionality tests, triggers for introduced bugs, patches, and performance monitoring tools, enabling benchmarking of patching tools and bug mitigation strategies.

The CBs were originally developed for DECREE -- a custom Linux-derived operating system that has no signals, no shared memory, no threads, no standard libc runtime, and only seven system calls -- making them incompatible with most existing analysis tools. In this repository, we have modified the CBs to work on Linux and OS X by replacing the build system and re-implementing CGC system calls via standard libc functionality and native operating system semantics. Scripts have been provided that help modify the CBs to support other operating systems.

The CBs are the best available benchmark to evaluate program analysis tools. Using them, it is possible to make comparisons such as:

  • How good are tools from the Cyber Grand Challenge vs. existing program analysis and bug finding tools?
  • When a new tool is released, how does it stack up against the current best?
  • Do static analysis tools that work with source code find more bugs than dynamic analysis tools that work with binaries?
  • Are tools written for Mac OS X better than tools written for Linux, and are they better than tools written for Windows?

Components

challenges

This directory contains all of the source code for the challenge binaries. Challenges that are not building or are not yet supported are in the disabled-challenges directory.

include

This directory contains libcgc, which implements the syscalls to work on non-DECREE systems. libcgc currently works on OS X and Linux.

tools

This folder contains Python scripts that help with modifying, building, and testing the original challenges.

tester.py

This is a helper script to test all challenges using cb-test. Results are summarized and can be output to an excel spreadsheet. More details in the testing section below.

Building

To build all challenges, run:

OS X/Linux:
$ ./build.sh
Windows:
> powershell .\build.ps1

This command will build both the patched and unpatched binaries in build/challenges/[challenge]/.

Testing

The tester.py utility is a wrapper around cb-test that can be used to test challenges and summarize results. The cb-test tool is a testing utility created for the DARPA Cyber Grand Challenge to verify CBs are fully functional.

cb-test has been modified to work with a custom server. All changes include:

  • Starting cb_simple_server.py instead of cb-server
  • Always running the challenges on localhost
  • Skipping any checks that verify the file is a valid DECREE binary
  • Lessening sleeps and timeouts to allow tests to run at a reasonable rate

Options

-a / --all: Run tests against all challenges
-c / --chals [CHALS ...]: Run tests against individual challenges
--povs: Only test POVs for every challenge
--polls: Only test POLLs for every challenge
-o / --output OUTPUT: Output a summary of the results to an excel spreadsheet

Example Usage

The following will run tests against all challenges in challenges and save the results to out.xlsx:

$ ./tester.py -a -o out.xlsx

To run tests against only two challenges, do this:

$ ./tester.py -c CADET_00001 CROMU_00001

To test all POVs and save the results, run:

$ ./tester.py -a --povs -o out.xlsx

Types of Tests

All tests are a series of input strings and expected output for a challenge. There are two types of tests that are used:

POV (Proof of Vulnerability): These tests are intended to exploit any vulnerabilities that exist in a challenge. They are expected to pass with the patched versions of the challenges, and in many cases cause the unpatched version to crash.

POLL: These tests are used to check that a challenge is functioning correctly, and are expected to pass with both the unpatched and patched versions of challenges.

Type 1 POV notice

Verifying type 1 POVs relies on analyzing the core dump generated when a process crashes. They can be enabled with:

OS X:
$ sudo sysctl -w kern.coredump=1
Linux:
$ ulimit -c unlimited
Windows:

Merge tools/win_enable_dumps.reg into your registry. Note that this will disable the Windows Error Reporting dialog when a program crashes, so it's recommended that you do this in a VM if you want to keep that enabled.

Current Status

Porting the Challenge Binaries is a work in progress, and the current status of the porting effort is tracked in the following spreadsheet:

https://docs.google.com/spreadsheets/d/1Z2pinCkOqe1exzpvFgwSG2wH3Z09LP9VJk0bm_5jPe4/edit?usp=sharing

Notes

Windows support is coming soon!

The challenge binaries were written for a platform without a standard libc. Each binary re-implemented just the necessary libc features. Therefore, standard symbols were redefined. By using the -nostdinc flag during compilation, we were able to disable the use of standard library headers, and avoid rewriting a lot of challenge binary code.

We use the CMake build system to enable portability across different compilers and operating systems. CMake works across a large matrix of compiler and operating system versions, while providing a consistent interface to check for dependencies and build software projects.

We are working to make this repository easier to use for the evaluation of program analysis tools. If you have questions about the challenge binaries, please join our Slack and we'll be happy to answer them.

Authors

Porting work was completed by Kareem El-Faramawi and Loren Maggiore, with help from Artem Dinaburg, Peter Goodman, Ryan Stortz, and Jay Little. Challenges were originally created by NARF Industries, Kaprica Security, Chris Eagle, Lunge Technology, Cromulence, West Point Military Academy, Thought Networks, and Air Force Research Labs while under contract for the DARPA Cyber Grand Challenge.

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