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Home / Tips and Tricks / Using Ubuntu as Your Primary Operating System, Part 1 (Physical Attack Defense) «Null Byte :: WonderHowTo

Using Ubuntu as Your Primary Operating System, Part 1 (Physical Attack Defense) «Null Byte :: WonderHowTo

Windows 10 and macOS have a bad reputation when it comes to customer privacy and user policies. In addition, our steady stream of hacking Windows 10 and hacking MacOS articles may mean that a reasonably secure operating system does not exist. But I'm here to tell you that there is a viable alternative that could provide a degree of certainty and confidence.

There are some notable Linux distributions with excellent development records and support communities to choose from. Just to name a few, there are Manjaro, BlackArch, Parrot Security OS, and Kali, but I've decided to use Ubuntu for several reasons:

  • Ubuntu has a strong support community . This is the main reason for choosing Ubuntu over other popular Linux distributions. Compared to others, Ubuntu has a large support community found on Ask Ubuntu, UbuntuForums and on many IRC channels. In my experience, these beginner communities are very receptive and will make it easier for users to transition from a Windows 1
    0 home environment.
  • No bloatware . Unlike Windows 10 and macOS, the Ubuntu installer provides the ability to integrate only essential software. That means you're rid of ridiculous games, commercial products, and preinstalled software that wastes RAM and CPU resources.
  • Installing Kali Tools is easy . Thanks to the Katoolin project, it is possible to quickly install hacking tools on Ubuntu found in Kali Linux. I do not necessarily advise users to install such tools on an Ubuntu machine, but I think that zero-byte readers will appreciate it.
  • Low System Requirements . The Ubuntu developers recommend only 2 GB of system memory (RAM) to operate the operating system (OS). I could run it comfortably with only 1GB of RAM, and lightweight distributions like Xubuntu to just 512MB. I have not been able to count how many old computers have brought Ubuntu back to life, thanks to its ability to run smoothly on old hardware.

If you now set up an Ubuntu system, you need to be mindful of some security concerns. After the initial installation, there will be some tasks that you would like to run for a more secure system, but we will cover them in future parts of this miniseries.

Overall, this series is geared toward Windows 10 users interested in switching to Ubuntu, so I'm starting to rebuild the operating system from scratch. Readers who already have Ubuntu installed can jump to later parts of the series if they are available.

Disclaimer: These articles are not intended as an ultimate guide to hardening or as a preventive guideline for defending against governmental agencies. These are just a few simple things that can help Ubuntu users improve their defense against physical attacks and on public Wi-Fi networks.

Step 1: Download the Ubuntu ISO

To protect Ubuntu from physical attacks, Ubuntu should be hardened from the ground up during installation. First, download the latest Ubuntu ISO, verify the ISO and create a live USB. I recommend Etcher, a cross-platform live USB creator.

Insert your USB flash drive into your computer, select "Select image" in Etcher, and then select the downloaded Ubuntu IOS. Next, select "Connect a drive" or simply select "Drive" and choose your USB stick. Click on "Flash!" and wait until it's done

Step 2: Starting Ubuntu Live USB

On the computer where you install Ubuntu Boot from your new one Live USB.

The key required to start the Live USB depends on the manufacturer of your computer. Many OEMs use F12 as Dell and Lenovo. ASUS uses the key Esc . If you are not sure, consult your OEM's online documentation. You can also start your computer normally to see what it is; After the first boot, many computers will display the boot menu shortcut key.

If necessary, select your Ubuntu Live USB drive, then select "Install Ubuntu" or something similar to begin the installation. 19659018] Step 3: Minimize the attack surface

Use the "Minimal installation" option in the installer. This does not help with physical attacks, but it can only be done during the initial installation. Minimizing the number of packages installed prevents Ubuntu from loading unnecessary applications. If it is discovered tomorrow that [Transmission] a popular torrent application, or Thunderbird, a popular e-mail client, are vulnerable to a new exploit, your system will be completely unaffected.

Minimal installation reduces attack surface for applications It may be discovered that they contain vulnerabilities in the future. Third-party applications and commercial software can be installed at any time at a later time as needed.

Step 4: Defend Against Hard Drive Forensics

There is a steady tug of war between security and convenience. Doing something secure means it's inconvenient to access it. If you want to make things more comfortable, you have to confuse them …

Do not think that protecting your hard drive is worth anything – never underestimate your value to hackers. You must not leave sensitive files in the Documents folder or compromise photos in your image library. However, web browser cookies that log you in to a web site can still be extracted. Files and photos that have been "deleted" from the Recycle Bin can be dug up in forensic attacks and brought back to life.

To enable encryption during installation, you must enter a password each time you start it to unlock the hard disk and load the operating system. There is no doubt that many of you will find that uncomfortable. However, encrypting your hard drive will protect your data if an attacker physically removes the hard drive for forensics. It also protects against single-user attacks in which the device is turned on with a privileged boot mode.

Ubuntu's default encryption settings actually provide a high level of protection against brute-force attacks. However, using a complex passphrase over 16 characters is still recommended.

Step 5: Defending Against Sudo Abuse

After selecting "Install Now" will give you the "who are you." ? " displayed. Screen. Yes, that means another password that you need to remember. This password is used to log in to the newly created user account (the "Your Name" part) when the computer wakes up from hibernation or hibernation and when sudo is used to execute privileged commands. [19659002] As someone who uses sudo often, I fully understand how uncomfortable it can be to enter a complex password several times a day. However, it is important to set a strong password here as well . Someone with physical access to an unlocked operating system can guess a weak password and execute a vicious command with elevated privileges.

Step 6: Defense Against USB Rubber Ducky Attacks

By default, Ubuntu operating systems are just as vulnerable for USB Rubber Ducky attacks like Windows 10 or MacOS. Such attacks can be prevented by denying Ubuntu the ability to fully accept input from USB mice and keyboards. For desktop users, this may not be a realistic option. Laptop users who never use external keyboards can appreciate this change.

To disable external mice and keyboard input, use the following command. USB mass storage devices can still connect to the operating system.

  sudo echo & # 39; blacklist usbhid & # 39;> /etc/modprobe.d/usbhid.conf

Then use the following update-initramfs command to update the boot configuration. Restart for the changes to take effect.

  sudo update-initramfs -u -k $ (uname -r)

update-initramfs: Generate /boot/initrd.img-4.15.0-23-generic

Next: Network Attack Defense

The above steps during installation should provide reasonable protection against physical attack. In the post-installable sections of this series, we'll talk about network security best practices, application hardening, and auditing tools that can be used to fix almost any operating system vulnerability. Stay tuned.

Title image after Pathompong Nathomtong / 123RF; Screenshots of tokyoneon / zero byte

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