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September 26, 2018 ยท View on GitHub

BinTut @@@@@@

.. image:: https://img.shields.io/pypi/v/bintut.svg :target: https://pypi.python.org/pypi/BinTut

Dynamic or live demonstration of classical exploitation techniques of typical memory corruption vulnerabilities, from debugging to payload generation and exploitation, for educational purposes :yum:.

Official Mirrors

What's BinTut

BinTut is a set of tutorials, as well as exercises.

Tutorials

See Get Started_ for usage information.

If you are a fan of Faiz_, Burst Mode or Single Mode should sound familiar and inspiring.

Burst Mode ++++++++++

Watch and replay to obtain general understanding of the process.

Use -b / --burst to control the interval (in seconds). Note that -b0 means Single Mode, which is the default.

Single Mode +++++++++++

Play and examine various contents such as the stack, registers or memory addresses, carefully and step by step, to acquire comprehensive and detailed knowledge of the process.

Use Enter or Ctrl + D to step.

You can execute normal GDB_ commands via the promt. But note that BinTut won't synchronize the display when you execute state-changing commands, e.g. stepi or nexti, which are discouraged for the time being.

Another bad news is that readline_ does not work :scream:, and I can't figure out the reason :scream:.

Exercises

Write exploits that work outside debuggers when you understand the principles and techniques via watching and replaying (i.e. rewatching), careful playing (i.e., Single Mode), and most importantly, reading the source code responsible for exploit generation, which resides in a file named exploits.py.

Installation

Notice

If pip_ is used to install BinTut, make sure that you use the pip_ version corresponding to the Python_ version shipped with GDB_. For more details, see #1_.

pip install bintut may or may not work for the time being.

Therefore it's recommended to just clone this repository and run without installation as long as necessary libraries are installed by pip install -r requirements.txt.

Warning

BinTut does not work inside virtualenv at present.

Tested Platforms

Arch GNU/Linux_ +++++++++++++++++

Current version of Arch GNU/Linux_ ships GDB_ with Python_ 3, in which I developed BinTut.

The latest release version should work fine.

  • Install lib32-glibc

    ::

    sudo pacman -S lib32-glibc

  • Install Python_ 3 and pip3.

    ::

    sudo pacman -S python python-pip

  • Install BinTut using pip3

    ::

    sudo pip3 install bintut

  • You are ready!

    ::

    bintut -b0.1 jmp-esp

Fedora GNU/Linux_ +++++++++++++++++++

The latest Fedora Workstation comes with GDB_ with Python_ 3, which has been tested and BinTut is known to work properly as in Arch GNU/Linux_.

  • Install glibc.i686 to support 32-bit programs if needed.

    ::

    sudo dnf install glibc.i686

  • Install BinTut from PyPI.

    ::

    sudo pip3 install bintut

  • Give it a try.

    ::

    bintut -b0.1 frame-faking

Debian GNU/Linux_ +++++++++++++++++++

GDB_ from the stable branch of Debian GNU/Linux_ ships with Python_ 2.

Latest source from Git works with minor problems.

  • Add support to 32-bit programs if necessary.

    ::

    sudo dpkg --add-architecture i386 sudo apt-get update sudo apt-get install libc6:i386

  • Clone the latest source code from Git and install requirements.

    ::

    git clone https://github.com/NoviceLive/bintut.git cd bintut sudo apt-get install python-pip gdb pip2 install -r requirements.txt

  • Run it without installation.

    ::

    python2 ./bintut.py -b0.1 frame-faking

Kali GNU/Linux_ +++++++++++++++++

GDB_ from the latest rolling version of Kali GNU/Linux_ ships with Python_ 3.

  • Enable i386 support according to aforementioned instructions.

  • Install pip3

    ::

    apt-get install python3-pip

  • Install the latest BinTut release using pip3

    ::

    pip3 install bintut

  • Start hacking!

    ::

    bintut -b0.1 jmp-esp

Requirements

GDB_ ++++

Python_ scripting support is required.

BinTut is developed with Python_ 3, but it's intended to be Python_ 2 compatible.

Therefore, when Python_ 2 yells at you, feel free to create an issue or send me a pull request.

Known unresolved issues existing on Python_ 2

  • Can't display disassembly after returning to shellcode.

  • Can't print the payload for some courses.

Ropper_ +++++++

Show information about binary files and find gadgets to build rop chains for different architectures.

pyelftools_ +++++++++++

Python library for analyzing ELF files and DWARF debugging information.

Pat_ ++++

Customizable Lazy Exploit Pattern Utility.

Colorama_ +++++++++

Simple cross-platform colored terminal text in Python.

Click_ ++++++

Python composable command line utility.

.. _Get Started:

Get Started

See bintut --help and give it a shot via bintut --burst 0.1 frame-faking.

::

./bintut.py --help Usage: bintut.py [OPTIONS] [COURSE]

 Teach You A Binary Exploitation For Great Good.

Options: -V, --version Show the version and exit. -l, --list List available courses. -6, --x64 Use x64 courses. -A, --aslr Enable ASLR. -b, --burst FLOAT Use this burst mode interval. [default: 0] -v, --verbose Be verbose. -q, --quiet Be quiet. -h, --help Show this message and exit.

Available Courses

Other courses might be added later.

Stack-based buffer overflow_

  1. plain ++++++++

Return to plain shellcode.

Linux x86 / x64.

NX: Disabled.

ASLR: Disabled.

Stack Protector: Disabled.

  1. nop-slide_ +++++++++++++++

Return to NOPs plus shellcode.

Linux x86 / x64.

NX: Disabled.

ASLR: Disabled.

Stack Protector: Disabled.

This course is not demonstrative enough and shall be updated when the author finds a scenario where nop-slide_ really stands out.

  1. jmp-esp ++++++++++

Return to shellcode via JMP ESP / RSP.

Linux x86 / x64.

NX: Disabled.

ASLR: Disabled.

Stack Protector: Disabled.

  1. off-by-one NULL ++++++++++++++++++

Variant of plain stack-based buffer overflow_.

Linux x86 / x64.

NX: Disabled.

ASLR: Disabled.

Stack Protector: Disabled.

  1. ret2lib_ +++++++++++

Return to functions.

Linux x86.

NX: Enabled.

ASLR: Disabled.

Stack Protector: Disabled.

.. _Notes for x64:

Notes for x64

Either on Linux or Windows, the ABI of x64_, unlike that of x86, passes some arguments, first six or four integral arguments on Linux or Windows respectively, via registers, which may not be controlled without resort to certain gadgets.

Therefore, it may be discussed in the section for ROP_.

  1. frame-faking +++++++++++++++

Return to chained functions via LEAVE RET gadget.

Linux x86.

NX: Enabled.

ASLR: Disabled.

Stack Protector: Disabled.

Notes for x64

See Notes for x64_.

Bug Reports

Create issues <https://github.com/NoviceLive/bintut/issues>_.

BinTut might or might not work on your system, but bug reports with necessary information are always welcome.

Tips

Remember to include bintut --version in your report.

You can just submit the verbose log (stderr) if out of words, e.g., bintut -v -b0.1 frame-faking 2>log.txt.

TODO List & You Can Contribute

  • Improve the code if you find something that can be done better.

    The codebase of BinTut can always be improved by those who have a deeper understanding of Python than the author.

    Also, there are hardcoded behaviors which can be generalized.

  • Change color scheme to red highlight when content changes.

    Currently, our color scheme remains unchanged, in predefined colors, which is just not eye-catching or obvious when we want to observe some significant changes in certain registers or specific memory locations.

    Here is an example of such change, the least-significant-byte of saved EBP / RBP being cleared due to an off-by-one NULL write.

    Ref. That's what you will expect in OllyDbg and probably many other debuggers will also behave in this manner.

    Ref. Some GDB_ enhancement projects have already implemented this.

  • Synchronize the display when executing state-changing commands.

  • Add course variants that does not allow NULL bytes.

    For example, add variant courses using strcpy instead of fread to trigger overflow, in order to demonstrate the techniques to survive in severe environments, which happen to be the case of our real world.

  • Use a better combination of chained functions for frame-faking.

    What follows is the current choice.

    Yes, two consecutive /bin/sh and exit.

    ::

    elif post == 'frame-faking': payload = ( Faked(offset=offset, address=addr) + Faked(b'system', ['/bin/sh']) + Faked(b'execl', ['/bin/sh', '/bin/sh', 0]) + Faked(b'exit', [0]))

  • Support demonstration on Windows and MacOS.

References

  • Smashing The Stack For Fun And Profit <http://phrack.org/issues/49/14.html#article>_
  • The Frame Pointer Overwrite <http://phrack.org/issues/55/8.html#article>_
  • Advanced return-into-lib(c) exploits (PaX case study) <http://phrack.org/issues/58/4.html#article>_

.. _Arch GNU/Linux: https://www.archlinux.org/ .. _Fedora GNU/Linux: https://getfedora.org/ .. _Debian GNU/Linux: https://www.debian.org/ .. _Kali GNU/Linux: https://www.kali.org/

.. _pip: https://pip.pypa.io/ .. _Python: https://www.python.org/ .. _Capstone: http://www.capstone-engine.org/ .. _filebytes: https://github.com/sashs/filebytes .. _#1: https://github.com/NoviceLive/bintut/issues/1

.. _GDB: http://www.gnu.org/software/gdb/ .. _Ropper: https://github.com/sashs/Ropper .. _pyelftools: https://github.com/eliben/pyelftools .. _Pat: https://github.com/NoviceLive/pat .. _Colorama: https://github.com/tartley/colorama .. _Click: https://github.com/mitsuhiko/click

.. _Stack-based buffer overflow: https://en.wikipedia.org/wiki/Stack_buffer_overflow .. _nop-slide: https://en.wikipedia.org/wiki/NOP_slide .. _ret2lib: https://en.wikipedia.org/wiki/Return-to-libc_attack .. _ROP: https://en.wikipedia.org/wiki/Return-oriented_programming .. _ABI of x64: https://en.wikipedia.org/wiki/X86_calling_conventions#x86-64_calling_conventions .. _readline: https://docs.python.org/3/library/readline.html .. _Faiz: https://en.wikipedia.org/wiki/Kamen_Rider_555