Note: this tutorial deals with privacy issues on
the net, and how to improve your anonymity, not how one can find
details about another person. This topic is discussed in the Information
Gathering tutorial, which is the sequel to this tutorial. Issues
such as under what conditions some of the details that can be
found about you according to this tutorial can be obtained and
how to conduct such privacy intrusions will be discussed in the
sequel tutorial.
In the mean time, you can read a little about the dangers themselves
and more about how to avoid them and improve your anonymity on
the net. Happy reading!
Preface: ph33r the net
Whether you realize it or not, the Internet is not as anonymous
as you might think. Here are a few examples:
1) You enter a website. Once you hit any one of the files on
the webserver, the website owners can find out these pieces of
information about you, and much more:
1. Your IP Address.
2. Your hostname.
3. Your continent.
4. The country you live in.
5. The city.
6. Your web browser.
7. Your Operating System.
8. Your screen resolution.
9. Your screen color depth.
10. The previous URL you've been to.
11. Your ISP.
12. Your Email address.
13. Your MAC address. (don't know what a MAC address is? Everything
will be explained later)
14. What kinds of browser plug-ins you have installed.
15. Wether you have Java and Javascript support turned on or off.
16. Any information that is stored in your cookies file. (don't
know what cookies are? Everything will be explained later)
17. Other private details.
And that is just the tip of the iceberg.
Can you guess who gives away all of this information? Well, I'll
give you three guesses... your web browser? Yes, that's correct,
your web browser gives a lot of information about you because
some websites use this information to customize the page depending
on your resolution, screen color depth and more, and some sites
read the last URL you've been to in order to know whether you
reached that page from the author's site or whether you reached
that page from a different site (meaning that some other webmaster
is "leeching off" their files). Other websites use this information
for other purposes...
Just to show you how much information your browser gives away,
let me show you how a typical MSIE HTTP request (a request from
an HTTP server to download a page or a file) looks like:
GET /texts/internet%20security/anonymity.html HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/vnd.ms-powerpoint, application/vnd.ms-excel,
application/msword, */*
Referer: http://www.www.securitywriters.org/networking_security.html
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.0; Windows 98)
Host: 62.0.96.180:8011
Connection: Keep-Alive
See what I'm talking about?
Guess number two... TCP/IP itself? Yup, true, TCP/IP itself provides
the website with your IP address and your MAC address (this part
will be explained later on), which can then be used to find your
hostname, which can be used to find your place of living or at
least where your ISP is located.
Guess number three... the user itself? You guessed correctly again,
my friend. Wow, you're really getting the hang of this! ;-) Anyway,
the point is that lots of stupid users tend to trust every site
with their private details and fill every form they see without
making sure that the site has a valid privacy policy.
So what can we do about it? Well, a lot. But let's leave that
to later, shall we? We will discuss anonymous surfing in the anonymous
surfing chapter.
2) Another example: you're connected to an IRC network and you
are chatting with your friends. Right now all a person who is
connected to the same IRC network needs in order to find information
about you is nothing but your nickname. He doesn't even have to
know you, or be in the same channel/channels you are. Here are
a few examples of what anybody can find out about you (in the
most optimal conditions) by simply knowing your nickname:
1. Your real name.
2. Your Email address.
3. Your IP address.
4. Your hostname.
5. Your ISP.
6. Your continent.
7. Your country.
8. Your city.
And again, there could be more. The reasons? You name it. TCP/IP,
the IRC protocol, Silly users...
There's a lot you could do in order to improve your anonimity
on IRC networks, but we'll discuss this issue in it's appropriate
chapter.
The same goes for online games, instant messengers, Usenet networks,
Emails and everything else you do on the net. Have I convinced
you yet? :-)
Some of you are anxious to continue reading and improve their
anonimity. Others have been convinced that the Internet is not
anonymous, but don't see why they should make any efforts to anonymize
themselves - don't worry, you will be given reasons, just keep
on reading. And last but not least, some of you may still be skeptical
about whether doing all those things and finding all of this information
just by having someone visit your web site or finding someone
on ICQ really is possible - for people like you and other curious
boys and girls, I have written the information gathering tutorial,
which can be found at www.securitywriters.org's texts library
as well. It will teach you how to do all of those things and much
more!
| Chapter
I: testing yourself |
So... how anonymous are YOU??
Yes, you, right there, on the other side of the monitor. What,
you think I can't see you? This is the Internet, not Television!
Yes, there's a monitor and there are pictures and sounds and issues
of public interest, but it's completely different! The net controls
you! The net owns you! Everything you say, everything you do,
it's all recorded and stored permenantly on a hundred thousand
different servers on the Internet! They control everything - your
computer, your TV set, your phone, your car, your air conditioner,
your nearest Supermarket's price scanner... even your underwear!
They know anything and everything, they know me and you, and they
know EXACTLY what you've been hiding in your socks drawer (naughty
naughty you!).
The above part was completely unnecessary. I just felt like rambling.
Anyway, this chapter lets you, the reader, venture into the depths
of the net (how melodramatic) and try a few simple tricks on himself.
Let's begin with something easy: a web search.
Point your browser to http://www.whowhere.com/. Now, see if you
can find yourself, and see what kind of information you can find
about yourself. Try the different searches, and click on anything
you see. I managed to find my name, Email address, home address,
home phone number and much more, and I suspect that some of the
information was given by my ISP, and the rest was given by GeoCities.com,
which I signed up for (sometime in 1996, I think) when I built
my first web site.
Now let's try something else. We've already concluded that web
browsers send out a lot of data about you, and that web servers
can run software that logs this information and saves it for later
retrieval. But even people who own small websites and don't have
access to the actual server and can't install such software on
it or access it's logs can still get all of this information about
their visitors by subscribing to online web statistics services.
One such service is SuperStats, so point your browser to http://www.superstats.com/.
At SuperStats and other such services, Webmasters can sign up,
and then put a small portion of HTML code into any of their site's
pages and the web stats provider will kick in and do the rest
whenever someone enters that page. The process is fairly simple:
the code contains an instruction to the web browser to retrieve
a certain image from the webstats provider's server. When your
browser retrieves that information, it leaves it's footprint in
the webstats provider's server's log files (web browsers give
away a lot of information, remember?) and they do the rest of
the work.
Anyway, that site has a "live demo" button which can show you
just what kinds of information this service (and other similar
services) can capture.
I have just found a web page with a list of "environment variables
checkers". These are scripts that get those variables that your
browser gives away, and can show them to you. Check that page
out at http://proxys4all.cgi.net/env-checkers.shtml,
follow one of the links and see how this web script (and any other
web site) can find those details with extreme ease.
Now let's try some Emails. Send an Email to yourself, and when
you get it, access it's full headers. With MS Outlook, you can
do that by right-clicking on the message in your Inbox and clicking
on properties. With Netscape Communicator, this can be done by
clicking view, the headers, then all. So, now you can see how
Emails really look like, and guess what? They contain loads of
information about you! They can tell anyone who receives or intercepts
an Email from you lots of details about you, including the Email
client you're using and your operating system (these details can
be used to send OS-specific of mailclient-specific viruses to
your mailbox, which could infect your computer), and of course
many other details such as your ISP, the area of your living and
more.
For further information about mail headers, please read http://www.securitywriters.org/texts/internet%20security/tracemail.html
and http://www.securitywriters.org/texts/internet%20security/mailspam.html
See how easy it is to find information about you? And that's just
the beginning.
| Chapter
II: the first step in anonymizing yourself - Anonymous Surfing |
Why would you want to surf anonymously? Let me give you a short
reminder, and explain the situation a bit further.
First of all, we concluded that TCP/IP hands in your IP address,
and this address can be used to find out who your ISP is, and
possibly track your geographical location (wanna know how? Then
the information gathering tutorial at http://www.securitywriters.org/texts/internet%20security/www.securitywriters.org
is just for you!).
Now you must be asking yourself "why does TCP/IP give this information
if people can use it to find all of this information about me?".
Well, the answer is quite simple. TCP/IP has to put your IP address
in the IP header of the packets that you send, because otherwise,
how would the server that you are requesting the web page from
know where to send it back? If your packets won't contain your
IP address or will contain a fake address instead, you won't receive
the returning packets.
However, there's a workaround for this. What if you could tell
some sort of a public computer to retrieve the files for you,
and then have the public computer send the files to you? That
way, the IP address that will appear in the packets will be the
address of the public computer, and your IP will remain anonymous,
right? This is called bouncing, because you send the packet to
the public computer, and then the public computer sends the packet
to the web server, so your packet metaphorically "bounces" from
one computer to another in order to hide your true address. I
will explain how to bounce a connection to a web site in a few
minutes.
The other problem with TCP/IP is that it gives away your MAC address
too. Oh, wait, I haven't explained what a MAC address is!
Info Break: What is a MAC address?
A MAC (Media Access Control) address (also called an Ethernet
address or an IEEE MAC address) is a 48-bit number (typically
written as twelve hexadecimal digits, 0 through 9 and A through
F, or as six hexadecimal numbers separated by periods or colons,
i.e. 0080002012ef, 0:80:0:2:20:ef) which uniquely identifes a
computer that has an Ethernet interface. Unlike the IP number,
it includes no indication of where your computer is located.
To learn more about MAC addresses, head to WhatIs.Com's definition
of a MAC address at http://whatis.techtarget.com/WhatIs_Definition_Page/0,4152,212506,00.html.
Now, why a dial-up Internet user would have a MAC address is
really beyond the scope of this tutorial, but the point is that
you have such a thing, and since it's a 48-bit number, there are
billions of different combinations and your MAC address can be
used to identify you (not in a very reliable way, but it has a
good enough success percentage). This form of identification can
be used to track your online shopping habits, for example (it
is known that some online retailers pass this kind of information
from one another). So in other words, exposing your MAC address
isn't too good either.
So, the second privacy risk we talked about was your browser
giving all this information about your computer, right? And of
course, your cookies file is being exposed to the entire world.
Wait, I haven't even explained what cookies are yet!
Info Break: What are Cookies?
Webster dictionary defines a "cookie" as:
1 : a small flat or slightly raised cake
2 a : an attractive woman <a buxom French cookie who haunts
the... colony's one night spot -- Newsweek> b : PERSON, GUY
<a tough cookie>
3 cookie : a small file or part of a file stored on a World Wide
Web user's computer, created and subsequently read by a Web site
server, and containing personal information (as a user identification
code, customized preferences, or a record of pages visited)
Uhh... ignore the first two. So that's what a cookie is. Web
sites can instruct your web browser to save information into your
cookies file. Ever been to a site that has a login prompt that
offers you to "remember" your password? That's how it works -
your password is saved in your cookies file.
Looking for more information about cookies? Then I suggest that
you follow this link: http://whatis.techtarget.com/WhatIs_Search_Results_Exact/1,282033,,00.html?query=cookie
Now, the problem with the cookies file is that every site can
read it, not just the site that stored the cookie entry in the
first place. Today, most sites save passwords and other kinds
of sensitive information in an encrypted form, but encryptions
can be broken... so if you're entering a suspicious site, you
might want to access your browser's preferences and disable cookies,
so the suspicious site won't be able to read them.
Now, for the workarounds for these problems:
How to surf anonymously
There are several ways to surf anonymously. Each way has it's
pros and cons (advantages and disadvantages, respectively), and
blocks different kinds of information from leaking out.
The Anonymizer
This is probably the easiest way, but also the least convenient
way.
What is the Anonymizer: Anonymizer.com is a service that is given
to the web community for free, and can be upgraded for a certain
amount of cash. Anonymizer.com is also a completely anonymous
ISP (costs money. More information about this is available at
their web site).
How to use: simply go to http://www.securitywriters.org/texts/internet%20security/www.anonymizer.com
and type in the address that wish to go to.
Pros: * blocks EVERYTHING - IP, browser information, cookies,
anything.
* Easy to use.
Cons: * blocks EVERYTHING (what if you wanted to have cookies
support or any of the other things that Anonymizer blocks off?
Oops...)
* Annoying ads and page delays, but you can remove them by signing
up to their premium service (costs money).
Anonymous Proxies
A more convenient way, but only blocks your IP and your MAC address.
What are Proxy servers: Proxy servers are bouncers that are meant
for people like you and me who want to surf anonymously. They
will create the connection to the web server for you, therefore
eliminating all the privacy issues that derive from TCP/IP, but
they won't protect your cookies file (unless you disable cookies
in your browser's preferences dialog box), and they won't block
off all of the information that your browser sends out.
However, Proxies have another purpose. Some ISPs have a Proxy
server that caches (stores on it's hard drive) web sites. The
Proxy allows the ISP's users to use it, and when someone attempts
to retrieve a web page that has already been cached on the Proxy
server's hard drive, he can receive the files he requested directly
from the Proxy server (MUCH faster). The Proxy updates it's cache
memory several times a day, to make sure that it has the most
recent version of the websites it cached. Such Proxies can only
be used by the users of the ISP which owns the Proxies, and they
usually aren't anonymous.
How to use: first of all, you need to find a web Proxy. You can
find several working ones at Cyberarmy's Proxies list (http://www.cyberarmy.com/lists/proxy/)
or at Proxys4All (http://proxys4all.cgi.net/. This site also
has links to some other web-based Proxies like the Anonymizer).
Then, once you have a Proxy's address and the port that it uses
to accept connections (usually 8080 and 1080), you need to configure
your web browser to use it (just access the options/preferences
page and the rest should be a piece of cake).
Note: if web pages suddenly become unavailable, it means
that your Proxy server has gone down (it was shut off, moved to
a different address or no longer accepts connections), and you
must find another Proxy server.
Pros: * very easy to use - Once you have found a Proxy
and configured your web browser to use it, you won't have to worry
about it anymore.
Cons: * doesn't block the information that your web browser
hands out.
* Proxies can sometimes go down or stop accepting connections
from you for different reasons, and you'll be left alone in the
dark (until you switch to a different Proxy or stop using Proxies
at all).
* Using Proxies can sometime result in slower loading times, if
the proxy server is overloaded.
Chaining Proxies
More security, but longer load times.
What is chaining Proxies: remember I explained about bouncing?
So if you can bounce your connection over a Proxy server, why
can't you bounce your connection over several Proxy servers? Your
packets can bounce from one Proxy to another on a line. This is
called chaining Proxies.
How to use: it seems that different proxies can be chained in
different methods, but most Proxies can be chained by separating
their addresses with -_-. E.g.: http://proxy.spaceproxy.com/-_-http://anon.free.anonymizer.com:80/http://www.securitywriters.org.
Try it!
Don't like this method? Fine, you can also tell your browser to
set up chaining for you so you won't have to type those long addresses.
For more information regarding how to do that and pictures explaining
exactly what to do, head over to http://articles.etecc.com/chaining.php.
You can also try using a program called Webonycer. I uploaded
it to securitywriters.org, and you can download it from http://www.securitywriters.org/webonycer.zip.
This program can make some peoples' lives a lot easier.
Pros: * Better security. If someone would really want to
trace you, he will have to go through a lot more effort to track
you down.
Cons: * Makes pages load much slower (your packets go through
a longer route with each Proxy in the chain).
* You become dependant on more Proxies, so if one of the Proxies
in the chain goes down, then not only that you will need to find
another Proxy, you will also face a new problem - you won't have
a way to tell which Proxy went down (unless you test each Proxy
manually).
Surfing from a Shell Account
Slower, does not allow graphics but hides EVERYTHING.
What is surfing from a shell account: you can connect to a free
shell account provider and use Lynx, a text-based web browser
to surf the net. This is another form of bouncing, because again,
you request another host on the Internet to retrieve the website
for you, and it sends it back.
How to use: the easiest way is to connect to a telnet server such
as the one at the University of Kansas. Click here (telnet://ukanaix.cc.ukans.edu)
to telnet in, and then log in as www or lynx and you'll be able
to use Lynx to browse.
Pros: * Hides EVERYTHING.
Cons: * Hides EVERYTHING (in case you didn't want to hide
some of the details or use your cookies).
* Slower than direct surfing (like every kind of bouncing).
* No graphics support (this is Lynx, after all. It does not support
graphics, and neither does it support Java, Flash and other things
that require a graphical display).
Those are some of the things you can do in order to surf anonymously.
Of course, there are other methods - there always are. I tried
to give you a general taste of the mostly-used methods. If you
wish to learn more about this topic, the web is wide-open, and
web searches (especially at google.com, which is by the way my
favorite search engine) could find you everything. And of course,
there's always SWG's web forum (http://www.securitywriters.org/forums.html),
with the quickest responses in the world (questions are usually
answered in an hour or less). If you ever face a question which
you cannot solve by a thorough web search, come over to the Q&A
forum and me and the rest of the Q&A staff will happily help
you out.
P.S. don't forget the third reason for privacy intrusions:
stupid users! Make sure that a site has a privacy policy before
you enter any private details into a form!
| Chapter
III: Internet Relay Chat - can it be anonymous? |
IRC, Internet Relay Chat, is a great way to expose yourself to
the world. Really, IRC and privacy don't go well together. However,
online privacy on IRC has been steadily improving.
The Risks of IRC
Any common IRC'er can easily fetch several details about you.
First of all, there's your IP address. Anyone could type /whois
your-nick and see your IP address. Furthermore, that person can
also initiate a DCC (Direct Client Connection) connection with
you for a file transfer or for a DCC chat session and obtain your
IP by using a program that comes with every Internet-enabled Unix/Linux/Windows
installation - netstat. Netstat allows you to view every connection
made by or with your system over the Internet, and its status.
Once you accept a DCC request from an attacker, he can find your
IP because there is a direct connection between you and him, so
netstat would show your IP.
But the fun doesn't stop there. There's also a big deal with
the details you provide the IRC server with, such as your Email
address and your real name, if you have entered those details.
There's also the risk of compromising your passwords: several
IRC services, such as chanserv and nickserv (don't know what these
are? Read SWG's IRC guide. You can find it at SWG's Texts Library), require you to
enter a password which you can choose by yourself. When choosing
your password, DO NOT, I repeat DO NOT choose the
same password that you used for something else. In fact, it is
advised not to use any password twice anytime, anywhere, but IRC
is one of the worst places to use a password twice.
If someone manages to get your password by either breaking into
the IRC server or by pretending he's an IRCop and asking for your
password, he could use this password to gain access to anywhere
else you may have used this password (other services, your Email
account, your web site, your shell account etc'). Also, it's quite
easy to turn in your password by mistake. Many times I have seen
people typing in their passwords into a channel instead of into
a message window, thus revealing their passwords to practically
the entire world!
Anonymizing yourself on IRC
There are several steps you can take in order to assure your
online anonymity on IRC:
1. Don't type in your real name and your real Email address when
your IRC client asks you to, unless you want them revealed.
2. Don't use any passwords you use on IRC for anything else.
3. Choose IRC networks that hide your IP address! Also, when connecting
to a new network, read the motd (Message Of The Day) by typing
/motd and see if there's anything about hiding your IP address.
IRC servers that claim to hide your address usually spoof the
last part of your address (the last 8-bit digit), like that -
62.0.75.spoofed, which is enough in most cases.
4. Do not accept DCC requests from people you don't know. Even
if the IRC server hides your IP, it will be revealed through a
DCC connection since DCC is direct, and does not go through the
IRC server (that's why it is called Direct Client Connection).
5. Many servers hide your real IP address, but some require you
to tell them to do so. In order to do that, you must type either
/mode your-nick +x (replace your-nick with your nickname) or /mode
your-nick +z , depending on the server.
If you want further anonymity, you may also want to use suid.net,
the world's only (as far as I know) encrypted IRC network. It
is also considered secure because of the considerably low number
of netsplits, but that's beyond the scope of this tutorial.
| Chapter
IV: ICQ - the worst thing that ever happened to privacy |
ICQ is considered by most to be a security threat to its users.
During the course of its evolution, it has suffered from many
serious bugs and vulnerabilities, such as vulnerabilities that
allowed malicious users to probe another user for a lot of information,
or to launch attacks with serious effects, ranging from flooding
the user's ICQ client with messages, causing it to crash, stealing
his password or even breaking into his computer.
Vulnerabilities have come and gone, but many have stayed. During
this tutorial, we will focus on the simple vulnerability, which
is caused by the way that ICQ works, and therefore hasn't been
patched. It's the vulnerability that allows anyone to view your
IP address, and it exists because ICQ is a client-to-client program.
Even if you tell ICQ not to reveal your IP in the preferences
dialog box, under privacy, there are other ways a malicious user
might try to find it other than looking at your info and expecting
to find it there. Since ICQ is a client-to-client program, messages
and other ICQ events are transferred directly from one host to
another, without the interference of a server, meaning that if
you send someone a message or someone sends you a message, a socket
is created between your computer and the other person's computer.
What does this mean? This means that anyone who sends or receives
an ICQ event from you can use programs such as netstat to view
all existing connections, spot the one that belongs to you and
get your IP address!
Go ahead, try it. Press start, run, and then type command. A
DOS window will appear. Type netstat -A and you will receive a
list of existing connections, their status and other basic information
about them, as well as the IP of the other host which is connected
to you through that socket (unless this is a listening socket,
which is waiting for a host to connect to it. A listening socket
will not give you a "Foreign Address".
So why doesn't Mirabilis change that? Why doesn't it change ICQ
so all events are transferred through the server, so attackers
will send and receive events to and from the server and thus will
be unable to find other people's IPs? Simple. Because what kind
of a mad man would want all those millions of ICQ users moving
their traffic through his server? And though AOL (the current
owners of Mirabilis) has a lot of money and can probably pay for
all this bandwidth, why would they do that? They don't care about
your security, and they won't spend an extra cent to improve it.
As a result to that, new versions of the ICQ client are released
without being properly tested, and new holes are being frequently
discovered.
Of course, the fault is not Mirabilis's alonel. There are also
several user-inherent problems, caused by users that reveal private
information by writing it into their user account info. Everyone
can view your info, so don't reveal anything that you wouldn't
like to when you fill out the form in the ICQ account preferences
dialog box.
| Chapter
V: Electronic Mail - encryption and headers |
Email, too, is not as innocent as it may seem. In order to teach
you why, and how to make your Emails a bit more anonymous, you
should learn about Email headers.
E-mail headers appear at the top of every Email message that
you receive, although you may not see them unless you tell your
Email client to show them (Outlook users: right-click on the message
in the inbox window and choose properties, then details. Netscape
Messenger users: press view, then headers, then all). Email headers
contain all sorts of details, some of which are collected by the
SMTP server which the sender used to send his Email, some have
to do with the process of the delivery of the message and some
are other details, like the MID (Message ID). Let's take a typical
header for example:
Envelope-to: raven@mail.box.sk
Received: from [194.90.1.9] (helo=mailgw2.netvision.net.il)
by dwarf.box.sk with esmtp (Exim 3.20 #1 (Debian))
id 155wUP-00015d-00
for <raven@mail.box.sk>; Fri, 01 Jun 2001 23:29:50 +0200
Received: from ***sender's name removed*** (ras1-p88.hfa.netvision.net.il
[62.0.96.88])
by mailgw2.netvision.net.il (8.9.3/8.9.3) with SMTP id AAA14549
for <raven@mail.box.sk>; Sat, 2 Jun 2001 00:32:06 +0300
(IDT)
From: "***sender's name removed***" <***sender's
address removed***>
To: "Raven" <raven@mail.box.sk>
Subject: securitywriters.org
Date: Sat, 2 Jun 2001 00:24:30 +0200
Message-ID: <MABBIBPFAKENJLPBHEDLAEAHCAAA.***sender's address
removed***>
MIME-Version: 1.0
Content-Type: text/plain;
charset="windows-1255"
Content-Transfer-Encoding: 7bit
X-Priority: 3 (Normal)
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0)
Importance: Normal
X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200
Status:
Well, that's nice. Look at all this information which is hidden
in every Email message you send! Everyone with a bit of knowledge
about Email headers can find out lots of details about you. Of
course, I had to remove the sender's name and Email address in
order to preserve his privacy, but I left the rest of the details
untouched.
So, what do we have here? Except for the regular details (sender's
Email address and his name, which he defined for his Email client
when he first configured it), we also have the sender's IP address
(or the IP address he had while he sent the mail, in case he has
a dynamic IP address).
Another thing you should do if you wish to achieve maximum privacy
is to encrypt your Emails. That way, you can assure that noone
who intercepts your message in one way or another, or breaks into
the recipient's Email account will be able to read it. PGP is
the most common mean of encrypting Email. Get it from PGP
International.
Info Break: What is a dynamic IP address
Dynamic IP addresses, as opposed to static IP addresses, change
every time you go online. While users with a permanent connection
have a static IP which does not change, dial-up users and other
kinds of users which don't have a permanent connection receive
a different IP address each time they go online.
But that's not all. In addition to the sender's IP
address, we can also tell what Email client software he used (unless
he forged these details, but that's beyond the scope of this tutorial.
If you wish to learn how to do that, consult Raven's Introduction
to Complete Newbies and Hacker Wannabes, Episode I). There are
several steps you can take in order to hide those and other details
about yourself.
1. Use an Email client that doesn't identify itself
(there are several ones on the net. Do a web search), or send
Emails by connecting to an SMTP server with Telnet and sending
the Emails manually. If you wish to learn how to do that, consult
the Hack FAQ.
2. Use anonymous remailers.
3. Use any other method of bouncing your connection, such as bouncing
it over a shell account or a Wingate computer or any other kind
of proxy that will allow you to bounce a connection to port 25
(that's the port which SMTP servers listen to, and that's the
port an Email client connects to when sending Emails).
| Chapter
VI: Usenet - not just news anymore |
Once a huge Internet community, Usenet is now known by a very
small percentage of the users in the world. Usenet is like a BBS,
which is a Bulletin Board System. Basically it's very much alike
today's forums, which every self-respecting site or portal now
has. Messages, also known as articles or posts are stored in a
central database where users can browse through the articles to
find the piece they want. Indexing and cross-referencing options
are also available. This is very helpful because it is easy to
find the information you need, and it's much more convenient to
have a central server than having all of this content stored on
your computer.
By posting to Usenet, you reveal your Email address. This means
two things:
1. You cannot post anonymously.
2. You are very likely to receive junk mail.
How do we get rid of that problem and post to Usenet while keeping
our Email addresses private, then? Well, there are several methods.
1. Use a commercial service for posting messages anonymously.
Some are free, some cost money, but anyway, it's worth it. I recommend
trying services such as http://www.nymserver.com/, http://www.mailanon.com/ (has a 7 day trial
period) and http://www.deja.com/.
2. Don't post with your real Email address. Instead, open up another
address for posting on Usenet at Hotmail, for example.
3. Use a mail-to-news gateway service to post. Such services allow
you to post to Usenet by Email. But instead of sending your Emailed
posts from your real address, send it from a fake address or using
an anonymous remailer.
4. Last but not least, some of the services listed above will
still reveal your IP address. In order not to reveal it, use a
proxy server to bounce your connection over it, so only the proxy's
IP address will be revealed.
Since the collapse of the NASDAQ, software companies have been
trying to find new ways to make money. They realized that shareware
doesn't work - most people prefer not to buy the full program
or download a crack for the program and get all of its features
rather than to pay for it, and only a few people actually buy
software. Several solutions were invented. One of those is Adware.
Adware is software that contains advertisements, which
earn revenue for the software company that distributed the program.
However, the Internet advertising business is sinking, and advertisers
pay less for advertisement space on the Internet. This is why
Spyware was invented.
Spyware is a program that literally spies on its user.
There are different kinds of Spyware programs, which differ from
one another by the kind of information they collect. Some collect
information about what kinds of programs are installed on your
computer, others collect information about your surfing habits
and others may get your Email address and the addresses of all
those in your address book and sell them to spammers for tons
of cash (as far as I know, the standard fee for a thousand valid
Email addresses is approximately 100$). As far as I know, some
may go as far as recording conversations you have over the Internet.
This information is later sold for a lot of money
to different companies that may be interested in this kind of
information (trust me, there are a lot). This is bad because:
1. This hurts your privacy.
2. Transmitting the data which the program collected wastes your
bandwidth.
To fight Spyware, you can use programs that detect
and remove Spyware from your computer, such as OptOut and Ad Aware.
You can find these programs at every self-respecting download
site.
Here's how to remove Spyware:
There are many online forums, chatrooms and websites
that deal with Spyware. Google.com, the best search engine in the world
(in my opinion) lists over 32,000 different webpages that mention
the word Spyware at the moment, and that's a lot, considering
the fact that this is a relatively new topic.
Many sites offer lists of Spyware programs and information
about them (including information on which files to remove in
order to disable the program's spying abilities). Do a web search, you'll
find plenty.
| Chapter
VIII: Browser History, Cache, Cookies and Autocomplete |
Your own Internet browser can turn you in! Imagine
what would happen if your girlfriend would find out about all
those sex sites you surf to, or if your boss would find out where
you've been surfing while you were supposed to do some work, or
some idiot posting some embarrassing items out of your browser's
history. Unless you know how to properly clean your browser's
history, you'd never know when you'd get caught with your pants
down (literally).
Your browser's cache database is also a problem. But
first of all, we have to understand what cache means.
Info Break: What is cache?
Cache is defined as a storage area that contains data that your
computer will need to use in a short time. There are different
hardware and software that use cache. For example, every modern
CPU (Central Processing Unit) has a cache memory chip installed
next to it, which stores data that the CPU will need shortly.
Accessing the cache is much faster than accessing any other kind
of storage device, and takes a lot of load off your RAM.
Internet browsers also use a certain form of cache memory. They
save web pages, including pictures, on your hard drive. Then,
the next time you access those sites, your computer will access
the site from the local cache instead of from the Internet. In
order to assure that the version of the site which is stored on
your local cache on your hard drive is up to date, your browser
compares the size of the files in your cache to the size of the
files on the web server and download whatever has been changed.
If you wish to download a site from the Internet completely and
overlook the local cache, you can either set your browser's preferences
to do so or press Refresh (IE) or Reload (Netscape).
The size of your browser's cache can be limited to a certain
amount, if you wish to save disk space, but know this about any
kind of cache space - the bigger, the better.
Now that you know what your browser's cache is used
for, you have probably realized that cache is a privacy risk.
People can search your cache memory to find out which sites are
cached, therefore learn where you've been surfing recently. However,
unlike clearing your browser's history, clearing your cache has
a drawback to it - you'll have to download the pages that were
deleted from your cache again the next time you go there instead
of being able to load them from your cache.
Another risk is cookies. We've already established
what these are in the first chapter, so let's suppose that you
know what they're for. So obviously, if you have a cookie that,
say, saves your username and password for some sex site so you
won't have to type them in every time you enter the site, won't
anyone who is able to lay hands on your cookies file know that
you've been there? Unfortunately, clearing your cookies has its
drawback as well - you'll have to delete all those stored preferences
and passwords, so do this only if you wish to obtain maximum privacy
at this high cost.
And finally, there's another risk that only exists
for IE users. This is called Autocomplete. Autocomplete is a new
IE feature that allows IE to remember what you typed into web
forms and allow you to enter the same data into them the next
time you visit that site in a mouseclick. I'm sure you can already
imagine what huge privacy risks this involves...
I will explain how to clear your browser's history,
your cache and your cookies to IE and Netscape users, and how
to turn off Autocomplete to IE users, since these are the most
common Internet browsers. Those using other browsers will have
to look up information on their own.
How to clear your browser's history:
There are several ways to do this. First of all, you
can do this manually. Instead of explaining here, I've decided
to refer you to this
site, because it has images along with the explanations of
how to clear your history. Make sure that the cleanup removed
the records of the sites you've been to both from your history
page and the address pulldown box, which also shows the last places
you've been to.
If you'd rather automate the process, you can use
a number of very useful tools, such as Evidence Eliminator (a
very famous program. It also cleans up other kinds of evidence
that don't have anything to do with Internet surfing), Cover Your Tracks,
Don't Panic,
Siege Washer,
Webwasher (a personal
favorite) and ComClear
(for those who use Netscape under Linux and other Unix variants.
Has both a graphical, GTK+-based interface and a textual interface).
Many of the programs listed above can also delete your cookies
and clear your cache.
How to clear your browser's cookies:
Cookies are very easy to get rid of. The safest way
to get rid of your cookies is to delete the cookies file, a plain
text file often found somewhere under the directory where your
browser has been installed. If you wish, you can also use programs
such as Deleting
Cookies, which does the job.
How to clear your browser's cache:
To delete your cache, just do as follows:
Internet Explorer users, go to the Control
Panel, then choose Internet Options and choose to delete your
temporary Internet files (that's how IE calls your cache).
Netscape users, go to the preferences dialog box, then
open the advanced category, click on cache and choose to clear
both the disk cache and the memory cache.
How to turn off Autocomplete:
Open up Control Panel, click on Internet Options,
then go to the advanced tab and remove the tick mark from Autocomplete
(turned off by default).
The object of this tutorial was to teach you how unsafe
the Internet is and how many privacy risks there are on the net,
in hope to educate the average net user to become more aware of
risks and take steps to improve his privacy.
I believe that online privacy is very important, because
if your computer is exposed, everyone in the world can peek in.
Just like you won't give away your house key to strangers, you
should preserve your anonymity and privacy on the net. After all,
it's your right.