A serious security flaw has been discovered in Microsoft Internet Explorer.
Many people now write and send email in HTML format - so that it looks like a web page.
MSIE's built in email program will render them and open binary attachments such as photographs or other graphic files. In other words, malicious attachments such as viruses will be automatically executed when you open an infected email if the attacker makes a simple change to the email's headers. Microsoft has issued a security patch that you should install immediately if you are using MSIE 5.5 or 5.01 without service pack 2. See Microsoft's security alert for more details. Internet Explorer Versions 5 and 5.5.