A large number of viruses that send spam emails constantly propagate over the Internet. The emails generated by these viruses will generally include attachments. They might appear to come from a government agency (such as the CIA or FBI), or they might say that an account of yours is being cancelled, or they might ask you to verify information in an attached file.
The virus gathers email addresses from the infected computer from the Windows address book and from cached web files that are stored on that infected computer, then sends a copy of itself to email addresses from those domains. If you are seeing one of these emails, it could come from anyone that had visited the 'yourdomain.com' web site or that had sent or received an email from any address ending in '@yourdomain.com'. Since the virus spoofs the information about where it came from (the "from" address in the email), tracking the origin of these emails can be impossible.
In general, never open an attachment that appears suspicious or comes from an email address you do not recognize. If the email does not personally identify you in some way, it is likely malicious. We recommend deleting these emails and/or installing a virus-scanning program with up-to-date virus definitions that will detect these for you.
Below is a short list of popular antivirus software:
- Norton Antivirus - Very popular, well-supported antivirus program. Very quick response to new virus threats. Scans for spyware and monitors email. Updates automatically.
- McAfee Antivirus - Similar to Norton; another very popular, well-supported antivirus program. Updates automatically. Also available is the McAfee Internet Security Suite, which provides a wide range of online protection.
- AVG Antivirus (free edition) - A free product for non-commercial use. Includes disk and email scanning. Virus definitions updated frequently; software must be updated manually.
- Commercial AVG products - An expansive list of paid software, ideal for large networks and commercial use. Provides generally broader protection than the above free AVG service. Free 30-day trials are available.