Hacking passwords

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Hacking passwords

Types of Passwords
There are three main types of passwords.
11.1.1 Strings of Characters
At the most basic level, passwords are stings of characters, numbers and symbols. Access to a
keyboard or keypad allows entry of these types of passwords. These passwords range from the
simplest – such as the three digit codes used on some garage door openers – to the more
complicated combinations of characters, numbers and symbols that are recommended for
protecting highly confidential information.
11.1.2 Strings of Characters plus a token
The next level in passwords is to require a string of characters, numbers and symbols plus a
token of some type. An example of this is the ATM, which requires a card - the token - plus a
personal identification number or PIN. This is considered more secure, because if you lack
either item, you are denied access.
11.1.3 Biometric Passwords
The third level in passwords is the biometric password. This is the use of non-reproducible
biological features, such as fingerprints or facial features to allow access. An example of this is
the retinal scan, in which the retina – which is the interior surface of the back of the eye – is
photographed. The retina contains a unique pattern of blood vessels that are easily seen and
this pattern is compared to a reference. Biometric passwords are the most sophisticated and
are considered 'safer' but in reality a password that you 'carry' in your finger or eye is no safer
than a strong password that you carry in your head, provided that the software that uses the
password is correctly configured.
11.2 History of Passwords
Trivia in Password History:
In older versions of MS Excel and Word, passwords were stored as plain text in the document
header information. View the header and you could read the password. This is valid for all
versions older than Office 2000.
Windows once stored passwords as plain text in a hidden file. Forget your password? You
could just delete the hidden file, and the password was erased.
Early on, Microsoft and Adobe both used passwords to mean that a file was password
protected when opened with their applications. If you opened it with another application,
such as Notepad, the password wasn't necessary.
Microsoft Access 2.0 databases could be opened as a text file easily by just renaming them
with a “.txt” extension. Doing this allowed you to see the database data.
Adobe PDF files in versions 4.0 and older were printable and often viewable using Linux PDF
readers or Ghostview for Windows.
Wireless networks have a problem with encryption as the key for the encryption can be
guessed once you collect enough encrypted data out of the air to find the patterns and
guess the keys. With todays computing power in the normal home, the key can be cracked
almost immediately to find the password.
Bluetooth security is considered very secure, once it is setup. The problem is that bluetooth
transmits a unique, freshly generated, password between the devices to establish the
connection and the password is sent as plain text. If that password is intercepted, all future
transmissions for that session can be easily decoded.
Download a PDF file off the Internet and try opening it with other programs. How is the data
11.3 Build a Strong Password
The best passwords:
✔ cannot be found in a dictionary
✔ contain numbers, letters and those odd swear symbols on top of the numbers
✔ contain upper and lower case letters
✔ the longer the “stronger”
With a 2 letter password, and 26 letters in the alphabet, plus 10 numbers (ignoring symbols),
there are 236 possible combinations (687,000,000 possibilities). Increase the password length to
8 characters, and there are 836 combinations (324,000,000,000,000,000,000,000,000,000,000
There are many password generators available on the internet, but these will generate a
nearly impossible to remember password.
Try instead to use a seemingly random string of letters or numbers that you can easily recall.
For example:
gandt3b! (goldilocks and the 3 bears!)
JJPL2c1d (john, jill, paul, lucy, 2 cats, 1 d – the members of your household)
1. Create a strong password, that you could remember that scores well at the following web
page: http://www.securitystats.com/tools/password.php
2. Look at the Web pages for three different banks and find out what type of password is
needed to allow an account holder to access restricted information. Do the banks also
offer recommendations that would lead users to create strong passwords?
11.4 Password Encryption
People don't usually discuss password encryption, because there seems to be no options to
discuss – passwords are, by definition, encrypted. While this is usually true, encryption is not a
simple yes or no proposition. The effectiveness of encryption, usually described as its strength,
ranges from very weak to extremely robust.
At its weakest, we have passwords that have been simply encoded. This produces a
password that is not readable directly, but, given the key, we could easily translate it using a
computer, pen and paper, or a plastic decoder ring from a cereal box. An example of this is
the ROT13 cypher. ROT13 replaces every letter in a text with the letter that is 13 places away
from it in the alphabet. For example 'ABC' becomes 'NOP'.
Even when using algorithms that can more accurately be called encryption, the encryption is
weak, if the key used to generate it is weak. Using ROT13 as an example, if you consider the 13
place differential to be the key, then ROT13 has an extremely weak key. ROT13 can be
strengthened by using a different key. You could use ROT10, replacing each letter with the
one ten places forward, or you could use ROT-2, replacing each letter with the one two
places before it. You could strengthen it even more, by varying the differential, such as ROTpi,
where the first letter is shifted 3 places; the second, 1 place; the third, 4 places; the fourth, 1
place; and so on, using pi (3.14159265...) to provide a constantly varying differential.
Because of these possible variations, when you are encrypting any type of information, you
must be sure that you are using a reliable method of encryption and that the key – your
contribution to the encryption – will provide you with a robust result.
You must also remember that a good system of encryption is useless without good passwords,
just as good passwords are useless without good encryption.
1. Here is a list of fruits encoded using the ROT13 cypher. Try to decode them:
a) nccyr
b) benatr
c) yrzba
d) jngrezryba
e) gbzngb
2. Find a web page that will allow you to decode the ROT13 encoded words automatically.
3. There are many different systems that are called encryption, but the truth is that many of
these are simple encoding methods. A true encryption requires a password, called a key,
in order to be encoded or decoded. Of the following systems, which ones are true
methods of encryption and which ones are simple codes?
a) Twofish
c) RSA
e) AES
f) BASE64
h) TripleDES
i) ROT13
j) TLS
11.5 Password Cracking (Password Recovery)
Password cracking for illegal purposes is illegal. But if it is your password, then it's your
information. Once you password protect something, and then forget your password, you are
stuck. Hence password recovery.
Password cracking consists of a few basic techniques
“Looking around”: passwords are often taped to the bottom of keyboards, under mousepads,
posted on personal bulletin boards.
Brute force: just keep trying passwords until one works
Automated dictionary attacks: these programs run through a series of possible dictionary
words until one works as a password.
There are many programs available on the web to assist with password recovery on
documents. However, newer versions of programs are becoming more and more secure, and
therefore, more and more difficult to obtain passwords using the techniques above, or using
password recovery software.
Identify three different programs that are used for developing documents (text, spreadsheets,
archives) and also allow the use of passwords to limit access to these documents. Next, using
the Internet, find instructions on how to recover lost passwords for these files.
11.6 Protection from Password Cracking
Here are some suggestions on how to keep your passwords from being cracked:
1. Use strong passwords that cannot be determined by a dictionary attack.
2. Don't post your passwords near your computer.
3.Limit wrong attempts to three tries, then lock the account. The password must then be reset.
(This does not apply to documents or password protected zip files – they do not have lock out
4.Change passwords regularly.
5. Use a variety of passwords for different computers. Does this mean that you need to create
a unique password for everything? Absolutely not. Maintain a master password for things that
don't matter to you (perhaps the account you were required to create for TheSIMS.com or for
your account on the local newspaper). But use good passwords for anything that actually
needs to be secure.
Discuss with the class the recommendations found in
Further Reading
http://www.ja.net/CERT/Belgers/UNIX-password - deadlink
http://www.crypticide.com/users/alecm/-security.html - deadlink

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