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NOTE: With 2.15, we introduce the two-gadget disaptcher--this significantly expands possibilities with dispatcher gadgets. A lot of optimizations and additional new features have been added with 2.15 on May 26, 2021.

Update: November 29, 2021: I have uploaded the slides for @Hack in Ryadh and also a white paper on Shellcodeless JOP. The silent demo videos useed in the talk may be found here:

Current version: 2.15

The Jump-oriented Programming Reversing Open Cyber Knowledge Expert Tool, or JOP ROCKET, is a tool designed to help facilitate JOP gadget discovery in an x86 Windows environment. This tool was released at DEF CON 27, where it was the subject of a talk by Dr. Bramwell Brizendine and Dr. Josh Stroschein. A major update is under development was released this September, 2020, with minor updates planned in the near future.

Please navigate to in order to download this tool.

A number of major updates have occurred. It is recommended that any version prior to 2.15 be updated, to take advantage of the many updates. These include automatic JOP chain generation, discovering new types of gadgets, new types of dispatcher gadgets, and the two-gadget dispatchers. JOP ROCKET has also undergone many other important chances to enhance and optimize its performance and speed.

JOP ROCKET is a Python program utilizing the Capstone disassembly engine as well as other dependencies. This software exploitation tool is a fully featured artifact designed to facilitate Jump-oriented Programming. It is intended to be run on Windows.

Usage information is not available at this time beyond what is in the help menu. Constructing JOP exploits is not straightforward and is very nuanced, with some parallels but many differences from ROP. Please refer to DEF CON talk to see a brief demo.

This tool has been taught at Dakota State University in the doctoral program, as part of CSC 848: Advanced Software Exploitation, the most challenging course in the program. The students completed exploits that included bypassing DEP and ASLR.

Thank you to Austin Babcock for his help with various issues relating to the JOP ROCKET, including his install instructions. He is a master of JOP.

We have uploaded an archive here, JOP ROCKET challenge - toy, to allow interested parties to test and practice JOP on some sample toy binaries, using the JOP ROCKET. Can you bypass Data Execution Prevention (DEP)? This is good if you want to practice JOP on a binary that you know is guaranteed to be vulnerable and have the right gadgets. There is an easier and a harder version of the same binary. Though JOP likely will be harder the first time, until someone gets the hang of it. Once you master JOP with these binaries, you can try it on some real-world gadgets, assuming they have sufficient gadgets. If you are doing the dispatcher gadget paradigm, keep in mind you do need a dispatcher gadget. JOP is also possible mixed in with ROP, using a jop gadget to point to a RET, so JMP EDX could have EDX point to RET. This is more useful if you need just one or two JOP gadgets to make ROP work. The binaries in the archive should allow you to do use the dispatcher gadget paradigm in a few different ways though!

With the dispatcher gadget paradigm of JOP, you can 100% eliminate ROP, although it is easiest to start things off with two ROP gadgets, to load the dispatch table and the dispatcher gadget. The pre-built JOP chain will do this for you automatically, assuming they are present. From there, it can be pure JOP, using both indirect jumps and indirect calls (JMP EBX, CALL EDX, etc.).

Basic install instructions for JOP ROCKET

Step 1:

Install Python 2.7. The easiest way to do this will be from the website:

If you already have Python 3, you will still need to have Python 2.7 as the tool will not work properly with Python 3.

If you have both, you will need to add the special comment:


to the top of Then run with "py" rather than "python". This will ensure the program is run using Python 2.7. Alternatively, you can just do py -2

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Step 2:

install pip if it isn't already included with Python.

You will need to save the script provided and run it, as per the instructions on the link. If you run into an error, try using the “alternate” script.

If pip still doesn't work, try adding "C:\python27\Scripts" (or your corresponding directory) to your Path system variable:

  • Start
  • Right click Computer
  • Properties
  • Advanced System Settings
  • Advanced tab
  • Environment Variables

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Step 3:

Start installing dependencies with pip!

Note: Installations with pip should work using the Windows terminal, but may not work in a Cygwin environment. If using Cygwin, you may need to install with source code instead. This can be a more time-consuming endeavor, and you are referred to the latest documentation from the different makers of the dependencies.

  • pip install capstone

  • pip install pefile2

    • You will likely already have pefile installed with Python 2.7, but this version is old.

    • Pefile2 is what you need.

    • You may need to pip uninstall pefile to get the program to use pefile2.

  • Etc... A list of dependencies can be found at the bottom of this document. Each must be installed, if they are not already.

  • The two above are likely the only ones you will need to install yourself.

Many of the dependencies already come with Python. To list available modules, open a prompt:

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Look through the list and see if you have all the dependencies. For those you don't have, install with pip or via source code.


  • Capstone
  • pywin32
  • Pefile2
  • Ctypes

Note: pywin32 is used for Win32file and Win32api

Needed files:

You should have in one directory all five files,, lists,py,,, and To begin using the tool, run on command line, python filename.exe -- the filename.exe being the program you wish to obtain JOP gadgets or JOP chains for.


If you are getting errors like "SyntaxError: Missing parentheses in call to 'print'", it is likely running with Python 3. Try doing the fix outlined in Step 1 to make the program use Python 2.

Errors related to “lists” or “ui” likely are caused by the location of the and files. Make sure these files are in the same directory as

More advanced install steps

To utilize this in a Cygwin environment, you likely will need to install Capstone from the source. There are varous ways to do so, and Capstone's documentation provides assistance. Cygwin was originally used during the development of the tool, although this is no longer the case. JOP ROCKET v2.0 is untested on Cygwin, and command prompt is the recommended usage of JOP ROCKET. Note: Cygwin usage is no longer explicitly supported, and it is no longer recommended to be used with this program.

Basic Usage

More detailed usage information is forthcoming. Refer to the DEF CON 27 talk and the help sub-menu for assistance.

To get started though, you want to have the five Python files in the same directory:,,,, and Then run from command line. You can provide a local file in the install directory, but it will not be able to find modules/DLL's. To find these, the program must be installed, and the absolute path to the application can be supplied as input inside a text file that can be provided as an argument on the command line, e.g.

python input.txt

Inside input.txt, we would have the absolute path, e.g. C:\rocket2\sample_binary.exe. By providing the absolute path, you will be able to extract the modules to scan as well, if so desired. If you want to use JOP ROCKET with only the program in the local directory, it will only find gadgets for the image executable itself, i.e. no DLLs. To use it in that fashion, use the following syntax:

python sample_binary.exe

If the executable is in the same directory, you may use JOP ROCKET in the manner described above

Making sure you get ALL the modules/DLLs for a binary

When loading an executable or DLL to be analyzed, there are two approaches. The first is to simply place the executable in the same directory and run the program, using that as an argument, e.g. python binary.exe. This will enable the user to identify and extract many of the system modules. However, it will not find some of the non-system binaries. For comprehensive coverage, the user must supply the absolute path to the application in a text file and use that as input to ROCKET, e.g. python input.txt. This will then allow for ROCKET to locate, extract, and search non-system DLLs associated with the target application. Thus, it is generally recommended to supply the binary as input via a text file, as otherwise some DLLs may be excluded. E.g., python binaryToScan.txt. The binaryToScan.txt should contain the path for the binary, C:\Users\CoolPerson\Desktop\Instructions\targetBinary.exe

Memory Issues with Very Large Binaries

The 32-bit Python will choke on very large binaries. To be able to work with these, you must use 64-bit Python.

Here are some instructions from Austin on going from 32-bit to 64-bit Python: To install the 64-bit version of python2.7, first make sure the old installation has been uninstalled. After installing the 64-bit version, you may get some errors when importing libraries such as "DLL load failed: %1 is not a valid Win32 application". These occur because Python is trying to load the previously installed 32-bit versions. To fix this problem, use pip to uninstall the library. If both Python 2 and 3 are installed, make sure the correct version of pip is used by using it as "py -2 -m pip ".

Fixing the issue for capstone is straightforward:

py -2 -m pip uninstall capstone

py -2 -m pip install capstone

Errors regarding the win32api import are related to pywin32. Uninstalling this is more difficult as pip may not automate the process. It may have to be uninstalled manually by deleting the PyWin32 files within ...\Python27\Lib\site-packages.

Then, run:

py -2 -m pip install pywin32

Afterwards, finish the installation by running ...\Python27\Scripts\ -install


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