How I turned my phone into a hacking machine

There are probably hundreds (if not thousands) of tutorials on this, but since I wanted a portable, non rooted, disposable hacking device which has the ability to take calls (a.k.a a cellphone/smartphone), I decided to mod an android based device. I have done this earlier (probably 5 years back) by installing arch on my android phone on a separate partition and booting it. This can be done today as well but since I do not want to root my cellphone, and do not want to use proot/LibSDL, I decided to see what can be done in a non rooted environment.

Intended audience for this piece - anyone having a bit hands experience on linux. Consider this as my personal cliffnotes in case I have to do it again. Let me even include an age old Disclaimer (taken from XDA aeons ago):

I am not responsible for bricked devices, dead SD cards, thermonuclear war, or you getting fired because the alarm app failed. Please do some research before running commands. YOU are choosing to make these modifications, and if you point your finger at me for messing up your device, I will laugh at you.

My iPhone recently went kaput during a fated trip to Jubail, KSA, and I zeroed on an inexpensive, capable device (Motorola G4 Play for around ~120 USD) for which I won't feel bad in case it gets lost or breaks into a million pieces.

Well, the device specs are average, the phone feels rugged and the battery can be taken out by simply removing the cover (which is EXTREMELY important for me). It comes with Android 6.0 and probably will never get updated to Android 7.0 (owing to Lenovo's shitty firmware update cadence), but once I disabled a lot of applications, the phone feels quick and is a joy to use.

First things first -
Disabled : Chrome, Cloud Print, Device Help, Drive, File Manager, FM Radio, Google Japanese/Korean/Pinyin/Zhuyin Input, Google Play Movies, Google Play Music, Google Hangouts, Messenger, Photos, other motorola bloatware.

Doublecheck device administrators. I would have removed a lot more software but then, I will also be using this phone for making calls and for light personal use as well.

Installed : Firefox (with Ublock), ESFile Explorer, Termux, Hacker's Keyboard, Textra (for SMS), Quickpic, OpenVPN, SMS Backup+, FastHub (or Github), Fing (quick GUI based network discovery), Flud (Torrents), Google Authenticator, AndFTP, drozer agent, Packet Capture (Application specific packet capture), TOR and Phonograph (lightweight music application).

Once the device's innards are replaced with a bit more capable/lightweight software, I launched Termux which is probably the most important terminal emulator written for android. From its website

"Termux is an Android terminal emulator and Linux environment app that works directly with no rooting or setup required. A minimal base system is installed automatically; Additional packages are available using the APT package manager. "

Onwards we go.

I started by updating Termux and its inherent environment - apt update && apt upgrade
Installed python2, python3, nmap, openssh, git, python-pip,htop through relevant apt commands.
Installed metasploit through https://github.com/Auxilus/Auxilus.github.io/blob/master/metasploit.sh (turns out this script has been stolen by a lot of folks, like this guy over here, and this one for youtube likes).
Installed scapy.
Generated OpenSSH keys, configured OpenSSH to run into server mode so that I can login into my cellphone if required. Make sure you check the username with whoami before generating keys. Putty aficionados may want to convert id_rsa keys using puttygen before loading it.

Configured OpenVPN application to connect to my remote server. Added TOR support.
Authenticated Fasthub Application with my Github account through a personal access token.
Tested everything.
Generated a list of packages for later use by running the following command "dpkg --get-selections | cut -f1 > bkup_pack.txt".
Took tar backup of current Termux installation for later use, I admit it is a quick and dirty hack but it works. Yes, I tested it.

cd /data/data/com.termux/files
tar -cvzf /sdcard/Download/termux.tgz --owner=0 --group=0 home usr

For more adventurous souls, you can go ahead with a rootfs option - https://github.com/xeffyr/Termux-RootFS. A simple tutorial for this would be here, however during my experiments, I found it to be buggy and some applications do not work properly. Since I value stability and security over everything, I promptly reverted back to my old fs.

Does everything works? Hell yeah.