Why do you need a passwordPasswords are a common form of authentication and are often the only
barrier between a user and your personal information. There are several
programs attackers can use to help guess or "crack" passwords, but by
choosing good passwords and keeping them confidential, you can make it
more difficult for an unauthorized person to access your information.
Think
about the number of personal identification numbers (PINs), passwords,
or passphrases you use every day: getting money from the ATM or using
your debit card in a store, logging on to your computer or email,
signing in to an online bank account or shopping cart...the list seems
to just keep getting longer. Keeping track of all of the number, letter,
and word combinations may be frustrating at times, and maybe you've
wondered if all of the fuss is worth it. After all, what attacker cares
about your personal email account, right? Or why would someone bother
with your practically empty bank account when there are others with much
more money? Often, an attack is not specifically about your account but
about using the access to your information to launch a larger attack.
And while having someone gain access to your personal email might not
seem like much more than an inconvenience and threat to your privacy,
think of the implications of an attacker gaining access to your social
security number or your medical records.
One of the best ways to
protect information or physical property is to ensure that only
authorized people have access to it. Verifying that someone is the
person they claim to be is the next step, and this authentication
process is even more important, and more difficult, in the cyber world.
Passwords are the most common means of authentication, but if you don't
choose good passwords or keep them confidential, they're almost as
ineffective as not having any password at all. Many systems and services
have been successfully broken into due to the use of insecure and
inadequate passwords, and some viruses and worms have exploited systems
by guessing weak passwords.
How do you choose a good password?
Most
people use passwords that are based on personal information and are
easy to remember. However, that also makes it easier for an attacker to
guess or "crack" them. Consider a four-digit PIN number. Is yours a
combination of the month, day, or year of your birthday? Or the last
four digits of your social security number? Or your address or phone
number? Think about how easily it is to find this information out about
somebody. What about your email password—is it a word that can be found
in the dictionary? If so, it may be susceptible to "dictionary" attacks,
which attempt to guess passwords based on words in the dictionary.
Although
intentionally misspelling a word ("daytt" instead of "date") may offer
some protection against dictionary attacks, an even better method is to
rely on a series of words and use memory techniques, or mnemonics, to
help you remember how to decode it. For example, instead of the password
"hoops," use "IlTpbb" for "[I] [l]ike [T]o [p]lay [b]asket[b]all."
Using both lowercase and capital letters adds another layer of
obscurity. Your best defense, though, is to use a combination of
numbers, special characters, and both lowercase and capital letters.
Change the same example we used above to "Il!2pBb." and see how much
more complicated it has become just by adding numbers and special
characters.
Longer passwords are more secure than shorter ones
because there are more characters to guess, so consider using
passphrases when you can. For example, "This passwd is 4 my email!"
would be a strong password because it has many characters and includes
lowercase and capital letters, numbers, and special characters. You may
need to try different variations of a passphrase—many applications limit
the length of passwords, and some do not accept spaces. Avoid common
phrases, famous quotations, and song lyrics.
Don't assume that now
that you've developed a strong password you should use it for every
system or program you log into. If an attacker does guess it, he would
have access to all of your accounts. You should use these techniques to
develop unique passwords for each of your accounts.
Here is a review of tactics to use when choosing a password:
- Don't use passwords that are based on personal information that can be easily accessed or guessed.
- Don't use words that can be found in any dictionary of any language.
- Develop a mnemonic for remembering complex passwords.
- Use both lowercase and capital letters.
- Use a combination of letters, numbers, and special characters.
- Use passphrases when you can.
- Use different passwords on different systems.
How can you protect your password?
Now
that you've chosen a password that's difficult to guess, you have to
make sure not to leave it someplace for people to find. Writing it down
and leaving it in your desk, next to your computer, or, worse, taped to
your computer, is just making it easy for someone who has physical
access to your office. Don't tell anyone your passwords, and watch for
attackers trying to trick you through phone calls or email messages
requesting that you reveal your passwords (see
Avoiding Social Engineering and Phishing Attacks for more information).
If
your internet service provider (ISP) offers choices of authentication
systems, look for ones that use Kerberos, challenge/response, or public
key encryption rather than simple passwords (see
Understanding ISPs and
Supplementing Passwords for more information). Consider challenging service providers that only use passwords to adopt more secure methods.
Also,
many programs offer the option of "remembering" your password, but
these programs have varying degrees of security protecting that
information. Some programs, such as email clients, store the information
in clear text in a file on your computer. This means that anyone with
access to your computer can discover all of your passwords and can gain
access to your information. For this reason, always remember to log out
when you are using a public computer (at the library, an internet cafe,
or even a shared computer at your office). Other programs, such as
Apple's Keychain and Palm's Secure Desktop, use strong encryption to
protect the information. These types of programs may be viable options
for managing your passwords if you find you have too many to remember.
There's
no guarantee that these techniques will prevent an attacker from
learning your password, but they will make it more difficult.