Hack and / - Browse the Web without a Trace

Concerned about your privacy? It takes only a Knoppix disc and a few simple steps to browse the Web anonymously.

Is privacy dead? When I think about how much information my computer and my gadgets output about me on a daily basis, it might as well be. My cellphone broadcasts my general whereabouts, and my Web browser is worse—every site I visit knows I was there, what I looked at, what browser and OS I use, and if I have an account on the site, it could know much more.

Even if you aren't paranoid (yet), you might want to browse the Web anonymously for many reasons. For one, your information, almost all of it, has value, and you might like to have some control over who has that information and who doesn't. Maybe you just want to post a comment to a blog without the owner knowing who you are. You even could have more serious reasons, such as whistle-blowing, political speech or research about sensitive issues such as rape, abuse or personal illness.

Whatever reason you have for anonymity, a piece of software called Tor provides a secure, easy-to-setup and easy-to-use Web anonymizer. If you are curious about how exactly Tor works, you can visit the official site at tor.eff.org, but in a nutshell, Tor installs and runs on your local machine. Once combined with a Web proxy, all of your traffic passes through an encrypted tunnel between three different Tor servers before it reaches the remote server. All that the remote site will know about you is that you came from a Tor node.

Tor works well on its own for anonymity, but anyone who has access to your machine can see that you have it installed. In some situations, even possession of anonymizing software might implicate you if you work in a company or live in a country where it is frowned upon. However, even in these cases, if you have a Knoppix disc, you quickly and easily can set up an anonymous Web browsing environment that will disappear once you reboot your computer. Because Knoppix boots and runs completely from the disc, any changes you make to it are stored in RAM and are erased once you reboot the machine.

First, you need a Knoppix disc. If you have a fast Internet connection, download a CD or DVD image from the official Knoppix site and then burn it to disc. Otherwise, look on the official Knoppix page for links to retailers who will ship you a Knoppix disc for a fee.

Next, boot your Knoppix disc. Knoppix should attempt to get on the network automatically, but if it doesn't, click K→Knoppix→Network/Internet for network configuration options. Knoppix has a sophisticated system that allows you to write to all areas of the filesystem as though it were installed on a hard drive. Because of this, you actually can install Tor on Knoppix according to the official directions on the Tor site. First, click K→Knoppix→Utilities→Manager software in Knoppix to start Knoppix's package manager. Then, click Reload to get the latest list of packages, search for the privoxy and tor packages, and select them for installation (or, if you want a shortcut, simply open a terminal and type sudo apt-get update && sudo apt-get install tor privoxy).

Now Tor will be set up and running, but Privoxy still needs a bit of extra configuration to use Tor. Open /etc/privoxy/config in a text editor, and add this line to the top of the file (don't forget the trailing dot):

forward-socks4a / .

After that, find any lines that look like the following and comment them out with a #:

logfile logfile
jarfile jarfile

Finally, open a terminal and type:

sudo /etc/init.d/privoxy restart

And, Privoxy will be ready to use.

Although you could configure Iceweasel (Firefox's name on Knoppix) by hand to use Privoxy, there is a nice plugin created just for Tor. Open Iceweasel and go to https://addons.mozilla.org/firefox/2275 to install the Torbutton plugin. Once you install the plugin and restart Iceweasel, a button at the bottom right of Iceweasel will appear that says either “Tor Disabled” or “Tor Enabled”. Simply click the button to toggle the state, and the plugin will take care of the rest.

From here, you can browse the Web anonymously. If you have never used Tor before, it's worth noting that you might see a slowdown in performance, as your traffic does need to be encrypted and pass through three extra servers. Also, certain sites, such as Google, may appear in their German or Japanese versions, depending on which Tor node you exit through. Once you are finished, shut down the machine, and all traces of Tor, Privoxy and your browsing history will be erased.


Kyle Rankin is Chief Security Officer at Purism, a company focused on computers that respect your privacy, security, and freedom. He is the author of many books including Linux Hardening in Hostile Networks, DevOps Troubleshooting and The Official Ubuntu


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just plain doesn't work...

jixned's picture

It sure would be nice if this worked as easily as you outlined in the article. When I followed your instructions, I am greeted with a message in synaptic telling me that, by selecting to install tor, I must upgrade a number of other packages. When I try to upgrade, the progress meter stops at libc and I have to expand the details to see why it stopped. There, I am met with a prompt asking me if I want to upgrade libc now. I say yes, but it doesn't matter if I say no since the installation will just stop at that point. Selecting yes attempts to install libc, but errors out with this message:
Another copy of the C library was found via /etc/ld.so.conf.
It is not safe to upgrade the C library in this situation;
please remove the directory from /etc/ld.so.conf and try again.
dpkg: error processing /var/cache/apt/archives/libc6_2.7-3_i386.deb (--unpack):
subprocess pre-installation script returned error exit status 1
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:
dpkg: dependency problems prevent configuration of locales:
locales depends on glibc-2.7-1; however:
Package glibc-2.7-1 is not installed.
dpkg: error processing locales (--configure):
dependency problems - leaving unconfigured
Setting up gcc-4.2-base (4.2.2-4) ...

I've tried unsuccessfully to install tor and privoxy, but nothing seems to work... ideas?

problem solved.

Anonymous's picture

In case anyone is interested or has the same problem I did, I found a solution. prior to installing tor & privoxy, edit /etc/ld.so.conf and remove the line /usr/lib. Then continue with the installation.