If you're interested in security, you've probably already heard of security-focused Linux distros like Tails, Kali, and Qubes. They're really useful for browsing anonymously, penetration testing, and tightening down your system so it's secure from would-be hackers. Here are the strengths and weaknesses of all three.
It seems like every other day we hear about another hack, browser exploit, or nasty bit of malware. If you do a lot of your browsing on public Wi-Fi networks, you're a lot more susceptible to these types of hacks. A security-focused distribution of Linux can help. For most of us, the use cases here are pretty simple.
If you need to use a public Wi-Fi network at a coffee shop or the library, then one of these distributions can hide your traffic from someone trying to peek in. Likewise, if you're worried about someone tracking down your location—whether it's a creepy stalker or something even worse—randomizing and anonyming your traffic keeps you safe. Obviously you don't need this all the time, but if you're checking bank statements, uploading documents onto a work server, or even just doing some shopping, it's better to be safe than sorry.
All of these distributions can run in a virtual machine or from a Live CD/USB. That means you can carry them around in your pocket and boot into them when you need to without causing yourself too much trouble.
Tails Provides Security Through Anonymity
Tails is a live operating system built on Debian that uses Tor for all its internet traffic. Its main goal is to give you security through anonymity. With it, you can browse the web anonymously through encrypted connections.
Tails protects you in a number of ways. First, since all your traffic is routed through Tor, it's incredibly difficult to track your physical location or see which sites you visit. Tails doesn't use a computer's hard disk, so nothing you do is saved to the computer you're running it on. Instead, everything you're working on is stored in RAM and erased when you shut down. This means any sensitive documents you're working on are never stored permanently. Because of that, Tails is a really good operating system to use when you're on a public computer or network.
Tails is also packed with a bunch of basic cryptographic tools. If you're running Tails off a USB drive, it's encrypted with LUKS. All your internet traffic is encrypted with HTTPS Everywhere, your IM conversations are encrypted with OTR, and your emails and documents are encrypted with OpenPGP.
The crux of Tails is anonymity. While it has cryptographic tools in place, its main purpose is to anonymize everything you're during online. This is great for most people, but it doesn't give you the freedom to do stupid things. If you log into your Facebook account under your real name, it's still going to be obvious who you are and remaining anonymous on an online community is a lot harder than it seems.
Pros: Routes all your traffic through Tor, comes with a ton of open-source software, has a "Windows Camouflage" mode to make it look more like Windows 8.
Cons: Can't save files locally, slow, loading web sites through Tor takes forever.
Who It's Best For: Tails is best suited for on-the-go security. If you find yourself at coffee shops or public libraries using the internet a lot, then Tails is perfect for you. Anonymity is the game, so if you're sick of everyone tracking what you're doing, Tails is great, but keep in mind that it's also pretty useless unless you use pseudonyms everywhere online.
Kali Is All About Offensive Security
Where Tails is about anonymity, Kali is mostly geared toward security testing. Kali is built on Debian and maintained by Offensive Security Ltd. You can run Kali off a Live CD, USB drive, or in a virtual machine.
Kali's main focus is on pen testing, which means it's great for poking around for security holds in your own network, but isn't built for general use. That said, it does have a few basic packages, including Iceweasel for browsing the web and everything you need to run a secure server with SSH, FTP, and more. Likewise, Kali is packed with tools to hide your location and set up VPNs, so it's perfectly capable of keeping you anonymous.
Kali has around 300 tools for testing the security of a network, so it's hard to really keep track of what's included, but the most popular thing to do with Kali is crack a Wi-Fi password. Kali's motto adheres to "a best defense is a good offense" so it's meant to help you test the security of your network as a whole, rather than just making you secure on one machine. Still, if you use Kali Linux, it won't leave anything behind on the system you're running it on, so it's pretty secure itself.
Besides a Live CD, Kali can also run on a ton of ARM devices, including the Raspberry Pi, BeagleBone, several Chromebooks, and even the Galaxy Note 10.1.
Pros: Everything you need to test a network is included in the distribution, it's relatively easy to use, and can be run on both a Live CD and in a virtual machine.
Cons: Doesn't include too many tools for everyday use, doesn't include the cryptographic tools that Tails does.
Who It's Best For: Kali is best suited for IT administrators and hobbyists looking to test their network for security holes. While it's secure itself, it doesn't have the basic daily use stuff most of us need from an operating system.
Qubes Offers Security Through Isolation
Qubes is desktop environment based on Fedora that's all about security through isolation. Qubes assumes that there can't be a truly secure operating system, so instead it runs everything inside of virtual machines. This ensures that if you are victim to a malicious attack, it doesn't spread to the operating system as a whole.
With Qubes, you create virtual machines for each of your environments. For example, you could create a "Work" virtual machine that includes Firefox and Thunderbird, a "Shopping" virtual machine that includes just Firefox, and then whatever else you need. This way, when you're messing around in the "Shopping" virtual machine, it's isolated from your "Work" virtual machine in case something goes wrong. You can create virtual machines of Windows and Linux. You can also create disposable virtual machines for one time actions. Whatever happens within these virtual machines is isolated, but its not secured. If you run a buggy web browser, Qubes doesn't do much to stop the exploit.
The architecture itself is set up to protect you as well. Your network connection automatically gets its own virtual machine and you can set up a proxy server for more security. Likewise, storage gets its own virtual machine as well, and everything on your hard drive is automatically encrypted.
The major downfall with Qubes is the fact that you need to do everything manually. Setting up virtual machines secures your system as a whole, but you have to be proactive in actually using them. If you want your data to remain secure, you have to separate it from everything else.
Pros: The isolation technique ensures that if you do download malware, your entire system isn't infected. Qubes works on a wide variety of hardware, and it's easy to securely share clipboard data between VMs.
Cons: Qubes requires that you take action to create the VMs, so none of the security measures are foolproof. It's still totally susceptible to malware or other attacks too, but there's less of a chance that it'll infect your whole system.
Who It's Best For: Qubes is best for proactive types who don't mind doing a bit of work to set up a secure environment. If you're working on something you don't want in other people's hands, writing out a bunch of personal information, or you're just handing over your computer to a friend who love clicking on malicious-looking sites, then a virtual machine's an easy way to keep things secure. Where something like Tails does everything for you out of the box, Qubes takes a bit of time to set up and get working. Qubes user manual is pretty giant so you have to be willing to spend some time learning it.
The Rest: Ubuntu Privacy Remix, JonDo, and IprediaOS
Tails, Kali, and Qubes certainly aren't the only security-focused operating systems around. Let's take a quick look at a few other popular options.
- Ubuntu Privacy Remix: As the name suggests, Ubuntu Privacy Remix is a privacy focused distribution built on Ubuntu. It's offline-only, so it's basically impossible for anyone to hack into it. The operating system is read-only so it can't be changed and you can only store data on encrypted removable media. It has a few other tricks up its sleeve, including a system to block third parties from activating your network connection and TrueCrypt encryption.
- JonDO: JonDo is a Live DVD based on Debian that contains proxy clients, a preconfigured browser for anonymous surfing, and a number of basic level security tools. It's similar to Tails, but is a bit more simplified and unfamiliar.
- IprediaOS: Like Tails, IprediaOS is all about anonymity. Instead of routing traffic through Tor, IprediaOS routes through I2P.
Of course, none of these operating systems are particularly ideal for day-to-day use. When you're anonymizing your traffic, hiding it away, or isolating it from the rest of your operating system you tend to take away from system resources to slow things down. Likewise, the bandwidth costs means most of your web browsing is pretty terrible. All that said, these browsers are great when you're on public Wi-Fi, using a public computer, or when you just need to use a friend's computer that you don't want to leave your private data on.They're all secure enough to protect most of us with our general behavior, so pick whichever one is best suited for your particular needs.