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Virus Information Centre - Email Virus/Worm
What are Email Virus / Worms?
Unlike an attached
file that the user must execute, email viruses are actually
embedded within the email itself. Attachments may also be
involved and these attachments will automatically execute when
the user reads, or, in certain cases, previews the email. Thus,
email viruses differ from email-borne viruses, the latter
which require users actually open the attachment in order to
become infected. Historically, email viruses have targeted
Microsoft Outlook, Outlook Express, and Internet Explorer users, though theoretically
other mail clients could pose a risk. In any event, if an
attachment is involved, the user can still choose to open it and
become infected, as was the case with BadTrans.B, Nimda, Sircam, and the
destructive Klez Internet Worm. For this reason, it
is equally important to understand both how to prevent
attachments from being automatically executed by the mail client
and how to recognize potentially harmful attachment types.
How do I prevent email viruses?
- Rule 1: Identification: Understanding the nature of
the attachment is the first step towards email safety. Any
executable type attachment has the potential to be infected. This
covers a wide range of extensions, however most viruses arrive as
an attachment with a .exe, .bat, .scr,
.com, .lnk or .pif file extension.
- Rule 2: Intent: An executable type attachment should
not be opened unless it was specifically requested or expected.
Since email worms are sent to addresses found on infected users'
machines, just knowing the sender is no proof of intent. In fact,
odds are an email worm will arrive from someone you know and the
sender is oblivious to the viral email being sent from their
machine. If you receive such an email from someone you know,
email that person and ask if they intended to send you the
attachment. If you don't know the sender, stifle your curiosity
and delete the email.
- Rule 3: Necessity: This is the simplest rule to
follow, but one that many people ignore. If you do not need the
attachment, don't open it. Delete the email instead.
- Rule 4: Disable scripting: To date, email viruses have
taken advantage of security vulnerabilities found in Microsoft
Outlook and Outlook Express. However, any mail client that
supports HTML and scripting should be considered at risk.
- Rule 5: Patch your system: Microsoft routinely
releases approximately 100 security patches per year. Keeping
abreast of these and understanding which are applicable to your
system can be a daunting task. Microsoft simplifies this by
providing a
Windows update site. The site will automatically scan your
system and provide a list of recommended updates specific to your
operating system. Any included in the "Critical Updates" section
should be installed. Of course, security is an ongoing process as
new vulnerabilities are constantly discovered. You should make it
a point to pay periodic visits to the update site to ensure
necessary patches are in place.
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If you require professional assistance eradicating potentially destructive
viruses or malware from your system, simply call tech support at 905-685-1539 (select
option 3) and make an appointment to bring your computer in to Vaxxine. For a modest fee, we will
run a scan and rid your machine of all virus files.
*Some limitations may
apply depending on the virus and amount of damage.
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18 years of Reliable Internet Service, 28 years of Expert Computer Service. Call Vaxxine 905-685-1539
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