PoshC2 : Python Server for PoshC2

PoshC2 is a proxy aware C2 framework that utilises Powershell and/or equivalent (System.Management.Automation.dll) to aid penetration testers with red teaming, post-exploitation and lateral movement. Powershell was chosen as the base implant language as it provides all of the functionality and rich features without needing to introduce multiple third party libraries to the framework.

In addition to the Powershell implant, PoshC2 also has a basic dropper written purely in Python that can be used for command and control over Unix based systems such as Mac OS or Ubuntu.

The server-side component is written in Python for cross-platform portability and speed, a Powershell server component still exists and can be installed using the ‘Windows Install’ as shown below but will not be maintained with future updates and releases.

Also Read – PEpper : An Open Source Script To Perform Malware Static Analysis On Portable Executable

Linux Install Python3

Automatic install for Python3 using curl & bash

curl -sSL https://raw.githubusercontent.com/nettitude/PoshC2_Python/master/Install.sh | bash

Manual install Python3

wget https://raw.githubusercontent.com/nettitude/PoshC2_Python/master/Install.sh
chmod +x ./Install.sh
./Install.sh

Linux Install Python2 – stable but unmaintained

Automatic install for Python2 using curl & bash

curl -sSL https://raw.githubusercontent.com/nettitude/PoshC2_Python/python2/Install.sh | bash

Manual install Python2

wget https://raw.githubusercontent.com/nettitude/PoshC2_Python/python2/Install.sh
chmod +x ./Install.sh
./Install.sh

Windows Install

Install Git and Python (and ensure Python is in the PATH), then run:

powershell -exec bypass -c “IEX (New-Object System.Net.WebClient).DownloadString(‘https://raw.githubusercontent.com/nettitude/PoshC2_Python/master/Install.ps1’)”

Using older versions

You can use an older version of PoshC2 by referencing the appropriate tag. You can list the tags for the repository by issuing:

git tag –list

or viewing them online.

Then you can use the install one-liner but replace the branch name with the tag:

curl -sSL https://raw.githubusercontent.com/nettitude/PoshC2_Python/<tag name>/Install.sh | bash

For example:

curl -sSL https://raw.githubusercontent.com/nettitude/PoshC2_Python/v4.8/Install.sh | bash

Offline

If you have a local clone of PoshC2 you can change the version that is in use by just checking out the version you want to use:

git reset –hard <tag name>

For example:

git reset –hard v4.8

However note that this will overwrite any local changes to files, such as Config.py and you may have to re-run the install script for that version or re-setup the environment appropriately.

Running PoshC2

1. Edit the config file by running posh-config to open it in $EDITOR. If this variable is not set then it defaults to vim, or you can use –nano to open it in nano.
2. Run the server using posh-server or python3 -u C2Server.py | tee -a /var/log/poshc2_server.log
3. Others can view the log using posh-log or tail -n 5000 -f /var/log/poshc2_server.log
4. Interact with the implants using the handler, run by using posh or python3 ImplantHandler.py

Installing as a service

Installing as a service provides multiple benefits such as being able to log to service logs, viewing with journalctl and automatically starting on reboot.

• Add the file in systemd (this is automatically done via the install script)

cp poshc2.service /lib/systemd/system/poshc2.service

• Start the service

posh-service

• View the log:

posh-log

• Or alternatively us journalctl (but note this can be rate limited)

journalctl -n 20000 -u poshc2.service -f –output cat

Note that re-running posh-service will restart the posh-service. Running posh-service will automatically start to display the log, but Ctrl-C will not stop the service only quit the log in this case posh-log can be used to re-view the log at any point. posh-stop-service can be used to stop the service.

Issues / FAQs

If you are experiencing any issues during the installation or use of PoshC2 please check the known issues below and the open issues tracking page within GitHub. If this page doesn’t have what you’re looking for please open a new issue and we will try to resolve the issue asap.

If you are looking for tips and tricks on PoshC2 usage and optimisation, you are welcome to join the slack channel below.

License / Terms of Use

This software should only be used for authorised testing activity and not for malicious use.

By downloading this software you are accepting the terms of use and the licensing agreement.

Documentation

We maintain PoshC2 documentation over at https://poshc2.readthedocs.io/en/latest/

Find us on #Slack – poshc2.slack.com (to request an invite send an email to labs@nettitude.com)

Known issues

Error encrypting value: object type

If you get this error after installing PoshC2 it is due to dependency clashes in the pip packages on the system.

Try creating a virtualenv in python and re-install the requirements so that the exact versions specified are in use for PoshC2. Make sure you deactivate when you’ve finished in this virtualenv.

For example:

pip install virtualenv
virtualenv /opt/PoshC2_Python/
source /opt/PoshC2_Python/bin/activate
pip install -r requirements.txt
python C2Server.py

Note anytime you run PoshC2 you have to reactivate the virtual environment and run it in that.

The use of a virtual environment is abstracted if you use the posh- scripts on *nix.