KAAAAAAAK!
Alert readers will remember that I made this statement before:
"Before you write and tell me that some viruses can be activated
simply by opening an email, PLEASE remember I said "if you keep
your browser and email software updated." If you have an old, unpatched copy of Microsoft Outlook, then all bets are off."
Nonetheless, the rabid hordes descended wielding spears and axes.
Well, maybe that's not a very nice way to put it. Strike that...
Let's say the angry masses swarmed in, bearing clubs and torches.
Yeah, that sounds more like it...
Most of the people who responded to that article wrote to tell me
about N-I-M-D-A, the K-A-K worm, or one of its evil cousins that took
advantage of a problem in some versions of Microsoft Outlook and
Outlook Express. These nasties could in fact do damage when you
opened the message, either by clicking on it, or when it appeared in
the Outlook preview pane.
In my extensive research, these are the ONLY cases I know of where a
virus/worm thingie could affect a computer without relying on
unwitting users who open attachments indiscriminately. However,
patches for all of these bugs were available MONTHS (and in some cases
YEARS) before the virus writers created the viruses that exploit them.
Why is that? Basically, because virus writers are not the type of
people who do the research to find security glitches. They exploit
known security flaws, hoping to affect people who have not applied the
fixes.
"Let Me Make This Perfectly Clear"
I do not know of **ANY** automatic virus/worm/trojan that hasn't been
covered by a security fix. None. This includes "html viruses",
"malicious javascripts" and "infected hyperlinks". And that wierd
virus that your cousin Vinny heard about from his friend who lives
next to the police department in a major city. Yup, that one too.
I did qualify my statement that "you cannot get a virus just by
reading your email" with the importance of keeping your internet software up to date. There is so much unwarranted fear, media hype and
misinformation surrounding the subject of computer viruses and email
attachments. That's why I feel it is important to make people aware
that they are quite safe if they use updated email software and abide
by common sense handling of attachments.
I'll Have The Caveat, Please.
Honestly, I was afraid that if I made a statement like "in some
circumstances it IS possible to get a virus by opening an email" then
the rest of the message would be lost in the ensuing panic. Never
mind that this can only happen to people using old, unpatched email
software. Never mind that the fix for this problem has been available
for months or years. RUN FOR THE HILLS! THE VIRUSES ARE A-COMIN'!!!
I will continue to stand by my statement that "you cannot get a virus
just by reading your email" but I'll add the caveat "as long as your
email software is up to date". I was tempted to say "as long as you
don't use a Microsoft browser or email product" but then Bill Gates
might not invite me to his parties anymore. So I won't say that. :-)
If you use Thunderbird (Firefox's companion email program), or Eudora, or almost ANY email software NOT made by Microsoft, you don't have to worry about this problem, and viruses will only get you if you let them. Hey, that's kind of like the vampire thing -- they can't get you unless you invite them in.
Keeping Current
So how do you keep your software updated and make sure all the latest
security patches are applied? If you use Internet Explorer and/or a
Microsoft email program such as Outlook or Outlook Express, it's
important to use Windows Update regularly and download any Critical
Updates recommended for your system.
http://windowsupdate.microsoft.com
For most users, Windows Update will automatically notify you when an
update is available. But I recommend that you check once a week just
to be sure. And for extra safety, download the latest version of your
email and web browser software once every six months.
If you use Firefox, Netscape, Eudora or other Mac Internet software, here are some links to find new versions, upgrades or security patches:
+ WINDOWS UPDATE - http://windowsupdate.microsoft.com
+ FIREFOX - http://www.mozilla.org/products/firefox/
+ NETSCAPE - http://home.netscape.com/smartupdate
+ EUDORA EMAIL SOFTWARE - http://www.eudora.com
+ APPLE SOFTWARE UPDATE - http://www.apple.com/support/
Disable Windows Scripting
It's my understanding that you can avoid most Windows-based viruses
(including K-A-K, B-u-b-b-l-e-B-o-y, M-e-l-i-s-s-a, I-L-O-V-E-Y-O-U
and many others) by disabling a feature called Windows Scripting Host.
Some people warn that this will prevent some legitimate uses of Visual
Basic Scripting, but I did this two years ago and it's never caused a
problem for me. Click below for instructions:
http://www.sophos.com/support/faqs/wsh.html
What About That !000 Trick?
Maybe you've received a chain letter advising you to add a bogus
nickname of "!000" to your email address book to prevent viruses from
spreading. Read the article below by About.com columnist Mary
Landesman to see why it's bad advice.
http://antivirus.about.com/library/weekly/aa082801b.htm
Notes On Revealing Windows Filename Extensions
In my Virus Prevention 101 article, I warned that you should be
careful when using the apparent filename of an attachment as a guide
to whether or not you can safely open it. I gave instructions on how
to make Windows reveal the entire filename, but my very smart friend
Uzi Paz says: "Be aware that this doesn't always work." And he
explains in much greater detail in his "Security and Filename
Extensions" article how Gatus of Borg has deigned to hide certain file
extensions even when they are supposed to be unhidden; along with
instructions for revealing ALL potentially harmful file extensions,
without using run-on sentences or improperly-placed punctuation marks.
http://www.uzipaz.com/eng/safe.html
What About Macs? And Linux?
One thing I didn't mention before is that there are
very few viruses that affect Mac or Linux systems. This isn't because
those platforms are inherently safer than Windows PC's, or because
it's harder to write a virus for Mac or Linux. The reason has to do
with market share. Since Mac and Linux users represent less than 10%
of the computing population, virus writers generally choose to ignore
them.
If you're an Evil Hacker about to unleash a virus on the world, and
you want it to affect the maximum number of people, you'll write a
virus that affects Windows-based computers. That's not to say that
viruses don't exist outside the Windows world. They do, but they
number in the dozens, as opposed to the tens of thousands that
potentially threaten Windows users.
So what do I recommend for people who use Macs or Linux? Nothing
different, really. Don't open attachments unless you know these
three things:
- Who sent it (confirmed by phone or email)
- Why they sent it
- What it is
When It DOES Make Sense to use Anti-Virus Software
My conclusion in "Do I need anti-virus software?"was that anti-virus software is
a waste of time and money for most people. I stand by that statement.
I'm not saying that some horrible new virus won't be invented
tomorrow. Let's say an Evil Hacker does exactly that, and the virus
exploits a previously undiscovered security hole. Will your
anti-virus program protect you? Most likely NOT!
When a brand new virus hits the Net, it tends to make the rounds very
quickly. Tens of thousands of people can be infected worldwide, even
if they have dutifully installed A/V software -- because it will take
the A/V vendors 24-48 hours to update their software, and maybe
another day for your software to receive and apply the updates.
That is my primary concern with A/V packages. They give people a
false sense of security which probably makes them MORE likely to click
on just about any attachment because they think they're safe. I also
have concerns about A/V software because sometimes they interfere with
other legitimate programs or report "false positives".
However, there are always exceptions to the rule. For some people, it
makes a lot of sense to run anti-virus software. If you fall into one
of these categories:
- your job requires you to receive email attachments that
contain word processor or spreadsheet files
- you frequently download new software, or receive files on disks
- your computer is shared by others (especially children) who are
prone to clicking, opening or downloading almost anything, despite
repeated warnings, threats and knuckle-whacking
- you have a nagging suspicion that Cousin Vinny might be right
about that wierd virus, or the item above applies to you. :-)
...then you SHOULD use an anti-virus program.
I don't discount the fact that people do make mistakes. If using
anti-virus software makes you feel safer, if you understand that it's
not a GUARANTEE to keep you safe, if you don't mind spending the
money, then maybe it's right for you. You can find a bunch of popular
anti-virus packages here:
http://search.yahoo.com/bin/search?p=anti-virus