Easy as Pie

Currently, the Kaboxer developers have packaged three applications. I'll take a look at these applications from a user's perspective by installing a GUI application and a web application.

To recreate the examples, first install the main kaboxer tool (Listing 1, line 1). Then make sure that your user account belongs to the kaboxer group (Figure 1). If you want to know which applications are available in Kaboxer format as well as which ones you have installed, use the command from Listing 1, line 2 (Figure 2).

01 $ sudo apt install kaboxer
02 $ apt search --names-only '\-kbx$'
03 $ sudo apt install zenmap-kbx
04 $ sudo apt install covenant-kbx

Figure 1: If you want to use the container framework, make sure that your user account belongs to the kaboxer group.

Figure 2: With a search via apt, you can quickly determine which applications are in Kaboxer format.

First, I will test Zenmap, a graphical front end for the Nmap port scanner. Zenmap depends on deprecated Python 2 libraries, which makes any kind of normal software installation on Debian and its derivatives painful because Python 2 has been removed from the Debian repositories.

To set up Zenmap with less overhead, the Kali developers offer the zenmap-kbx package (Listing 1, line 3) as one of their first Kaboxer applications. Figure 3 shows the installation process, which also creates an entry in the desktop menu structure (Figure 4). You can set up Covenant, a .NET-based command-and-control framework including a web front end (Figure 5) in the same way using the covenant-kbx package (line 4).

Figure 3: When installing Kaboxer packages via Debian's package system, the actual contents enter the system as a Docker image from the Kali developers' GitLab registry.

Figure 4: Kaboxer automatically creates an entry in the main desktop menu from which you start the container.

Figure 5: Covenant requires a bit more effort because you operate it via a web interface that the container launches in the browser.

Both apps work immediately. You will not even notice that they are running in containers. Covenant automatically launches its web interface. The Kaboxer version of Firefox as a full-fledged GUI application also performed without any issues in testing.

Disadvantages

Kaboxer apps take a little longer to install than traditional DEB packages. A Kaboxer application's tandem packages essentially function as a metapackage that downloads the content as a Docker image and then sets it up. However, you will not notice any further delays once you launch these apps.

The Kaboxer model has a disadvantage also common to Flatpak and Snap: file size. Even programs that are only a few kilobytes tend to swell to 50MB or more as Kaboxer containers due to the unavailable dependencies on the host system (or dependencies that might even be duplicated in the worst case scenario), as well as the container's overhead. Because of this, Kali Linux does not include these applications in its operating system images. Instead, you must install them manually if needed.

DIY

Setting up applications for Kaboxer is definitely not witchcraft. The tool's documentation describes the required steps in detail [2]. The steps include creating and building a Docker image of the corresponding application. For larger-scale deployments, it would make sense to automate the process via GitLab CI. For more information beyond what is described in the documentation, see the Kaboxer man pages and kaboxer.yaml.