When there are multiple people using your computer and/or you store
sensitive personal and work-related data on your computer, it is especially
important to take extra security precautions.
Why isn't "more" better?
Maybe there is an extra software program included with a program you bought.
Or perhaps you found a free download online. You may be tempted to install
the programs just because you can, or because you think you might use them
later. However, even if the source and the software are legitimate, there
may be hidden risks. And if other people use your computer, there are
These risks become especially important if you use your computer to manage
your personal finances (banking, taxes, online bill payment, etc.), store
sensitive personal data, or perform work-related activities away from the
office. However, there are steps you can take to protect yourself.
How can you protect both your personal and work-related data?
- Use and maintain anti-virus software and a firewall - Protect yourself
against viruses and Trojan horses that may steal or modify the data on
your own computer and leave you vulnerable by using anti-virus software
and a firewall (see Understanding Anti-Virus Software and Understanding Firewalls for more information). Make sure to keep your virus
definitions up to date.
- Regularly scan your computer for spyware - Spyware or adware hidden in
software programs may affect the performance of your computer and give
attackers access to your data. Use a legitimate anti-spyware program to
scan your computer and remove any of these files (see Recognizing and
Avoiding Spyware for more information). Many anti-virus products have
incorporated spyware detection.
- Keep software up to date - Install software patches so that attackers
cannot take advantage of known problems or vulnerabilities (see
Understanding Patches for more information). Many operating systems
offer automatic updates. If this option is available, you should turn it
- Evaluate your software's settings - The default settings of most
software enable all available functionality. However, attackers may be
able to take advantage of this functionality to access your computer. It
is especially important to check the settings for software that connects
to the internet (browsers, email clients, etc.). Apply the highest level
of security available that still gives you the functionality you need.
- Avoid unused software programs - Do not clutter your computer with
unnecessary software programs. If you have programs on your computer
that you do not use, consider uninstalling them. In addition to
consuming system resources, these programs may contain vulnerabilities
that, if not patched, may allow an attacker to access your computer.
- Consider creating separate user accounts - If there are other people
using your computer, you may be worried that someone else may
accidentally access, modify, and/or delete your files. Most operating
systems (including Windows XP and Vista, Mac OS X, and Linux) give you
the option of creating a different user account for each user, and you
can set the amount of access and privileges for each account. You may
also choose to have separate accounts for your work and personal
purposes. While this approach will not completely isolate each area, it
does offer some additional protection. However, it will not protect your
computer against vulnerabilities that give an attacker administrative
privileges. Ideally, you will have separate computers for work and
personal use; this will offer a different type of protection.
- Establish guidelines for computer use - If there are multiple people
using your computer, especially children, make sure they understand how
to use the computer and internet safely. Setting boundaries and
guidelines will help to protect your data (see Keeping Children Safe
Online for more information).
- Use passwords and encrypt sensitive files - Passwords and other security
features add layers of protection if used appropriately (see Choosing
and Protecting Passwords and Supplementing Passwords for more
information). By encrypting files, you ensure that unauthorized people
can't view data even if they can physically access it. You may also want
to consider options for full disk encryption, which prevents a thief
from even starting your laptop without a passphrase. When you use
encryption, it is important to remember your passwords and passphrases;
if you forget or lose them, you may lose your data.
- Follow corporate policies for handling and storing work-related
information - If you use your computer for work-related purposes, make
sure to follow any corporate policies for handling and storing the
information. These policies were likely established to protect
proprietary information and customer data, as well as to protect you and
the company from liability. Even if it is not explicitly stated in your
corporate policy, you should avoid allowing other people, including
family members, to use a computer that contains corporate data.
- Dispose of sensitive information properly - Simply deleting a file does
not completely erase it. To ensure that an attacker cannot access these
files, make sure that you adequately erase sensitive files (see
Effectively Erasing Files for more information).
- Follow good security habits - Review other security tips for ways to
protect yourself and your data.
Author: Mindi McDowell
The above article is reproduced with the kind permission of US-CERT (United States Computer Emergency Readiness Team) and the original document may be viewed by clicking here