FFM is a hacking harness that you can use during the post-exploitation phase of a red-teaming engagement. The idea of the tool was derived from a 2007 conference from @thegrugq.
It was presented at SSTIC 2018 (video) and the accompanying slide deck is available at this url. If you're not familiar with this class of tools, it is strongly advised to have a look at them to understand what a hacking harness' purpose is. All the comments are included in the slides.
This project is distributed under the terms of the GPL v3 License.
Check out the full documentation for the tool in this repo:
- With the diversity of modern terminal prompts, we highly recommend using
dockerwith this tool. - Utilizing the
Dockerfilein this repository will drastically cut down on potential errors encountered. - Utilizing a container to interact with remote hosts is also more secure. If you were to get exploited while interacting with a remote host, they would be sitting in your container vice your actual host. Lets still hope that does not happen.
- Ensure you have
Dockerinstalled on your local system
git clone https://github.com/JusticeRage/FFM.git
cd /FFM
docker build Docker_Install/ -t ffm:ffm
docker image list
REPOSITORY TAG IMAGE ID CREATED SIZE
localhost/ffm ffm fb6dd17e3b91 9 minutes ago 614 MB
docker.io/library/ubuntu 22.04 3b418d7b466a 2 weeks ago 80.3 MB
#run your new container and drop into a /bin/bash prompt as root
docker run -it --entrypoint /bin/bash -u 0 fb6dd17e3b91
- Once in your container set the
passwdforrootandneo su neoand now you are all set
- Not recommended
git clone https://github.com/JusticeRage/FFM.git
cd /FFM
pip install -r requirements.txt
The goal of a hacking harness is to act as a helper that automates common tasks during the post-exploitation phase, but also safeguards the user against mistakes they may make.
It is an instrumentation of the shell. Run ./ffm.py to activate it and you can start working
immediately. There are two commands you need to know about:
- Type
!listto display all the commands provided by the harness. - Type
!list tagsto see the differnt tags that commands can be binned under
!list tags
List of commands available:
enumeration
execution
help
stealth
transfer
- You can now type
!list enumeration(or one of the other tags) to see commands that fall into that category.
!list enumeration
List of commands available:
!backup-hunter: Hunts for backup files
!info: Returns CPU(s), Architecture, Memory, and Kernel Verison for the current machine.
!log: Toggles logging the harness' input and output to a file.
!mtime: Returns files modified in the last X minutes
!os: Prints the distribution of the current machine.
!db-hunter: Hunts for .sqlite, .sqlite3, and .db files
!sshkeys: Hunts for Private and Public SSH keys on the current machine.
!suid: Finds SUID, SGID binaries on the current machine.
--snip--
- Type
SHIFT+TABto perform tab completion on the local machine. This may be useful if you're ssh'd into a remote computer but need to reference a file that's located on your box.
This hacking harness provides a few features that are described below. As they are described, the design philosophy behind the tool will also be introduced. It is not expected that all the commands implemented in FFM will suit you. Everyone has their own way of doing things, and tuning the harness to your specific need is likely to require you to modify some of the code and/or write a few plugins. A lot of effort went into making sure this is a painless task.
!osis an extremely simple command that just runscat /etc/*release*to show what OS the current machine is running. It is probably most valuable as a demonstration that in the context of a hacking harness, you can define aliases that work across machine boundaries. SSH into any computer, type!osand the command will be run. This plugin is located incommands/replacement_commands.pyand is a good place to start when you want to learn about writing plugins.!backup-hunterHunts for backup files!infoReturns CPU(s), Architecture, Memory, and Kernel Verison for the current machine.!logToggles logging the harness' input and output to a file.!mtimeReturns files modified in the last X minutes. For example!mtime 5will get all files on the local machine (that you have rights to see) that have been modified in the last 5 minutes!db-hunterHunts for .sqlite, .sqlite3, and .db files and other database files!sshkeysHunts for Private and Public SSH keys on the current machine.!suidFinds SUID, SGID binaries on the current machine.!strange-dirsChecks device starting at user specified path for strange directories on a host!sudo-versionChecks for a vulnerable sudo version!vmChecks if device is a Virtual Machine
- Commands that help you pull and push files, pretty straight forward.
!download [remote file] [local path]gets a file from the remote machine and copies it locally through the terminal. This command is a little more complex because more stringent error checking is required but it's another plugin you can easily read to get started. You can find it incommands/download_file.py. Note that it requiresxxdorodon the remote machine to function properly.!upload [local file] [remote path]works exactly the same as the previous command, except that a local file is put on the remote machine.
!sh [local script]Runs a shell script from the local machine in memory.!py [local script]executes a local Python script on the remote machine, and does so entirely in memory. Check out my other repository for scripts you might want to use. This commands uses a multiline syntax with<<, which means that pseudo-shells that don't support it (Weevely is a good example of that) will break this command quite badly.!py3 [local script]does the exact same thing except for system with python3!elf3 [local script]Runs an executable from the local machine in memory, requires python3 on the remote machine.!elf [local script]Runs an executable from the local machine in memory, requires python2.7 on remote machine.
- I am fully aware these two modules are the opposite of "stealthy" but it is where they are currently placed until an alternative location can be worked out. This stealth category will more than likely contain commands that help you blend in better in addition to those commands that might make you stick out.
!ptyspawns a TTY, which is something you don't want in most cases because it tends to leave forensics evidence. However, some commands (sudo) or exploits require a TTY to run in so this is provided as a convenience.UNSET HISTFILE HISTFILESIZE HISTSIZE PROMPT_COMMANDis passed to it as soon as it spawns, along withexport TERM=xterm!sudoInvoke sudo without a TTY.
Plugins can be further configured by editing ffm.conf.
Conceptually, commands (as described above) are used to generate some bash which is forwarded
to the shell. They can perform more complex operations by capturing the shell's output and
generating additional instructions based on what is returned.
Processors are a little different as they are rather used to rewrite data circulating between
the user and the underlying bash process. While it is true that any processor could be rewritten
as a command, it seemed a little cleaner to separate the two. Input processors work on whatever
is typed by the user once they press the ENTER key, and output processors can modify anything
returned by the shell.
- A good processor example can be found in
processors/ssh_command_line.py. All it does is add the-Toption to any SSH command it sees if it is missing. Be sure to check out its simple code if you are interested in writing a processor. - Another input processor present in the framework,
processors/assert_torify.py, contains a blacklist of networking commands (ssh,nc) and blocks them if they don't seem to be proxied through a tool such astorify. The harness does its best to only bother the user if it seems like the command is being run on the local machine. Obviously this should not be your only safeguard against leaking your home IP address. - Finally,
processors/sample_output_processor.pyis a very simple output processor that highlights in red any occurrence of the word "password". As it's quite useless, it's not enabled in the framework but you can still use it as a starting point if you want to do something more sophisticated.
CTRL+R is not implemented yet and we all miss it dearly.
More problematic is the fact that the framework hangs from time to time. In 99% of the cases,
this happens when it fails to detect that a command it launched has finished running. Usually,
this means that the command prompt of the machine you're logged into could not be recognized
as such. In that case, you can try improving the regular expression located at the very
beginning of the file ffm.py, or log into that same machine with ssh -T as there won't be
any problematic prompt anymore.
By default, FFM will give up on trying to read the output of a command after 5 minutes (some
plugins may implement different timeouts); so if the framework hangs, you'll need to wait
until you see an error message (though if the underlying process is still running, you may
still not be able to type in commands).
I think I've covered everything about this tool. Again, it's a little different from what I usually release as most people will probably need to modify it before it can be valuable to them.
Many plugins have yet to be written, so be sure to share back any improvements you make to FFM. Feel free to open issues not only for bugs, but also if you're trying to do something and can't figure out how; this way I'll be able to improve the documentation for everyone.
- Directory download module
- Single file encryption module
