Everyone should know better, but executives seem to think they are special. Organized cyber-gangs are sending an e-mail message directly to small and midsized company’s CFO with an attachment that installs a tool to steal banking passwords. Then the criminals transfer money out of the company’s accounts.
This article from the Washington Post has more details: http://www.washingtonpost.com/wp-dyn/content/article/2009/08/24/AR2009082402272.html
The reason criminals keep using the same old tricks is that the tricks work. Warn your fellow executives and other workers about the importance of never opening attachments you were not expecting even if they appear to come from a trusted source. When in doubt, contact the sender to see if they really did send you an attachment.
Your IT department can help you scan the attachment for viruses, and some of you have services that scan all of your attachments. Just remember that the scanning may not catch the virus. Some viruses have new code every four hours so the anti-virus programs cannot keep up with the changes.
Practice many levels of protection and be wary!