With the high number of new threats appearing on the radars of anti-virus companies this year, it may come as no surprise that computers without virus protection only survive about 12 minutes once connected to the Internet.

According to the Sophos security company, compared to the first six months of 2004, the number of new threats that have appeared so far this year is up nearly 60 percent.

This statistic can largely be attributed to the makers of malicious software releasing hundreds of variations of threats rather than concentrating on one attack. One example is the Mytob family, which during a week in June released over 20 variations.

Sophos also released a list of threats that have been most prevalent this year. At number one, is the Christmas-time virus, Zafi.d. Although it uses a holiday greeting to trick you into opening the attachment, it's only been in recent months that occurrences of this threat have decreased.

Multiple variations of the Zafi, Netsky, Sober and Mytob threats round out the entire top ten which accounts for over 70 percent of all viruses reported to Sophos.

• Sophos' threat report
  
• Symantec's variation list (alphabetical)
  
• Panda Software's Zafi.d definition

Reading: Solutions, Prevention & Remedies

Additional summary information related to a specific type of solution or prevention that you should be considering. Depending upon the week, this section may have:

• Recent Windows security releases from Microsoft
  
• Recent updates to widely used anti-spyware programs
  
• Recent updates to widely used anti-virus programs
  
• Recent updates to other security programs & devices (ex: Firewalls, routers)
  
• Recent updates to various applications in wide use

Read: Top Threats
These are viruses that are currently on the watch lists of major anti-virus software companies.

Name
What the threat is called. We use the name given each virus by Panda Software. Sometimes other anti-virus companies give the same threat a different name. Usually they use similar names.

Type
There are different characteristics associated with different types of threats.

• Virus -- has the ability to replicate or infect computers or other programs
  
• Trojan Horse (or Trojan) -- appear to be harmless programs when you get them. They unleash their payload when you double-click, open, or execute them.
  
• Phishing -- a Web site or e-mail message posing as another company -- usually one you know to fool you into giving the sender personal information.
  
• Worm -- self replicates onto additional disks, computers or networks
  
• Spyware -- installs on your system to collect information about your activity, preferences or interests
  
• Hoax -- false messages sent by e-maill to mislead the recipient
  
• Backdoors -- opens a security hole that allows outsiders to take control of your computer
  
• Dialer -- uses your telephone to dial an outside number -- sometimes a number that costs you money when dialed

Alert level
The level of awareness that anti-virus vendors suggest you need to have for each threat listed. For each threat listed, we'll post a corresponding link here, so you can get more information to help you recognize, diagnose, prevent, and repair the problem.