Summary
An exploit is a short code or script that uses a vulnerability
to perform malicious actions.
The HTML.Mht exploit is embedded to HTML web pages. It attempts to
download and install a malicious program on your computer by using
a security vulnerability in Internet Explorer.
More information about this security vulnerability, including a fix, is
available from Microsoft:
http://www.microsoft.com/technet/security/bulletin/MS04-025.mspx