In the previous chapters, we have covered a wide variety of tools that Kali Linux offers a penetration tester. All of these tools are part of, or can easily be incorporated into, the Kali Linux platform. The one drawback to using these tools in a penetration test is portability. Even running Kali Linux on a laptop computer with an external antenna can be a cumbersome task. In certain circumstances, it may be conspicuous and alert our target. As a result, to give a greater degree of flexibility with those conducing, Offensive Security and members of the Kali Linux community have developed a version of Kali Linux called Kali Nethunter. This version of Kali Linux is specifically designed to run on the Android mobile platform, giving penetration testers a greater degree of flexibility and mobility.
Kali Nethunter has many of the tools we have discussed and some additional tools that allow for more mobile penetration testing. In this chapter, we will discuss installing Kali Nethunter and how the key tools can be put into action. Finally, there will be a discussion of use cases where the Nethunter platform has a significant advantage over trying to use a more traditional method of Kali Linux.
In this chapter, we are going to discuss the following:
Nethunter is the first mobile penetration testing operating system built on the Open Source Android platform. It was a collaborative development between Offensive Security and the Kali Community member "Binky Bear." Nethunter can be installed on the following Google Nexus devices; Nexus 5, Nexus 6, Nexus 7, Nexus 9, Nexus 10, and the OnePlus One. Offensive Security provides a number of Nethunter images based upon the device, and in some cases, the year of manufacturer.
Because of the collaborative nature of the production, Kali Nethunter is not supported by Offensive Security. As a result, some of the tools may or may not function based upon any number of factors. It is recommended that users test their tools out before moving toward a production environment or penetration testing engagement.
Due to its size, Nethunter can be deployed in three general ways. Each of these leverages tools within the Nethunter platform as well as additional hardware that can easily be acquired. These deployment strategies allow penetration testers to test a wide range of security measures found in a variety of environments.
The vast majority of previous chapters have been devoted to the tools and techniques available to the penetration tester for testing either remote or local networks. These tools require access to these networks through a physical connection. Nethunter has the same ability. Utilizing a combination of a USB Android adapter and a USB ethernet adapter, the penetration tester can connect directly into a wall jack or, if they are able to gain access to network hardware, directly into a switch.
This deployment strategy is good for those testers who may want to surreptitiously gain access to areas without the bulk of a laptop. Using a Nexus smartphone or even a small tablet, the penetration tester can connect to the physical network, compromise a local system and set up persistence there, and move one. This approach is also useful when testing the security around publicly available network jacks.
Chapter 12, Wireless Penetration Testing, was an in-depth discussion of how Kali Linux can be utilized to test the security of wireless networks. Nethunter includes a great many of the same tools in a portable package. In certain penetration tests, the ability to move around a large campus identifying networks and capturing wireless traffic for later cracking is made much easier with a tablet or smartphone testing platform rather than a laptop.
To deploy Nethunter in such a fashion requires the use of an external antenna and a USB to Android adapter. Once connected, these hardware tools allow for the full use of Nethunter's wireless tools.
One advantage that the Nethunter platform has over the Kali Linux platform is the native USB support found in the Android OS. This allows a penetration tester the ability to connect the Nethunter platform directly to hosts such as laptops and desktops. This ability allows the penetration tester the ability to utilize tools that carry out Human Interface Device attacks. In these attacks, the penetration tester is able to leverage tools that allow for connection to host devices and mimic what are known as Human Interface Devices (HID). HIDs are devices such as keyboards and mice that connect to the host via USB.
HID attacks use this feature to force the host system to perform commands or to download payload scripts directly to the system. What makes this attack significantly more difficult to stop is that event with data loss prevention controls that do not allow USB storage devices to connect, HID devices are allowed.