Before getting rid of an old computer or data storage device,
you should make sure that data stored on it has been
properly deleted. This is especially true if you stored
banking or credit card information, tax returns, payroll
information and other sensitive information on the device.
The question is, what is the best way to make sure this
data cannot be accessed after the device leaves your possession.
Reformatting a hard drive is not guaranteed to render data
inaccessible. Probably the best way to insure that nobody
can access the data is to physically destroy the device or
media. Unfortunately, this can often be too time consuming
or undesirable.
The next best option is to look into software and hardware
devices that claim to erase hard drives and/or CD's. These
programs and devices have varying levels of effectiveness.
When choosing a software program to perform this task,
make sure data is overwritten multiple times (3-7 times is
preferable). The software should also use random data
to overwrite your data because this makes it harder for
attackers to determine the pattern and discover the original
information underneath. It should also use all zeros to
overlay existing data in the final pass.
An 'insider threat' survey by the US Secret Service
and Carnegie Mellon University finds that 82 percent of
people who hack into their own company's systems 'exhibited unusual
behavior in the workplace prior to carrying out their activities.'
'Almost all - 96 percent - of the insiders were men, and 30
percent of them had previously been arrested, including arrests
for violent offenses (18 percent), alcohol or drug-related
offenses (11 percent), and non-financial-fraud related theft
offenses (11 percent).' It goes on to say that 86 percent held
technical positions at the companies: '...if you're going to fire
someone (particularly company geeks who have the motive, means
and access to inflict pain on your computer systems) make double
sure you cut off their e-mail and network access at the same time
you hand them their walking papers.'
The best way is to make sure your firewall is working is to
have a trusted firm (usually referred to as "white hat hackers")
do it for you. Of course, these firms charge for their services
and they are not cheap. If you are on a tight budget, you can
test your firewall yourself for free with Sygate Online Services.
Sygate Online Services (http://scan.sygate.com/
is a free web site that, with your permission, can probe your
firewall looking for vulnerabilities. Sygate Online Services
can scan computers running almost any operating system.
Active content and cookies are commonly used in web sites and may
pose hidden threats when sites using them are viewed in a browser.
Active Content
To increase functionality or add design embellishments, web sites
often rely on scripts that execute programs within the web browser.
This active content can be used to create "splash pages" or options
like drop-down menus. Unfortunately, these scripts are often a way for
attackers to download or execute malicious code on a user's computer.
Examples of active content are JavaScript, VBScript, and Java and ActiveX
controls. Keep in mind that many email programs use the same software
as web browsers to display HTML, so vulnerabilities that affect active
content like JavaScript and ActiveX often apply to email. Viewing
messages as plain text may resolve this problem.
Cookies
When you browse the Internet, information about your computer may be
collected and stored. This information might be general information
about your computer (such as IP address, the domain you used to
connect, and the type of browser you used). It might also be more
specific information about your browsing habits (such as the last
time you visited a particular web site or your personal preferences
for viewing that site).
To increase your level of security, consider adjusting your privacy
and security settings to block or limit cookies in your web browser.
To make sure that other sites are not collecting personal information
about you without your knowledge, choose to only allow cookies for the
web site you are visiting; block or limit cookies from a third-party.
If you are using a public computer, you should make sure that cookies
are disabled to prevent other people from accessing or using your
personal information.
If a computer gets infected with malicious virus, Trojan, worm,
keylogger, adware, etc., here are some things you can do to get back up and
running:
Minimize the Damage
Update your virus and scumware deffinitions for the software
you use.
Disconnect your computer from the Internet and your network.
This will stop your computer from infecting others on the
network and stop it from communicating information to some
"home base" out on the Internet. It will also make it
impossible for a remote user to access your hard drive.
Perform a manual virus and scumware scan of your entire system.
If the software can't locate and remove the infection, you
may need to reinstall your operating system. Note that
this will usually delete all of your files and any additional
software that you have installed on your computer.
Prevent Future Infections
Use and maintain anti-virus and anti-scumware software.
It is important to keep this software current.
Change your passwords regularly. Your original passwords may have been
compromised during the infection. This
includes passwords for web sites that may have been cached in your
browser.
Keep operating system and application software up to date.
Install all available patches as soon as they become available.
Install a firewall.
Follow good security practices - Be very careful when opening
email attachments, stay clear of porn web sites, etc.
