A Zero Day exploit utilizes software vulnerabilities to infect a system before it can be fully protected.
The Internet Explorer could be infected by malware on first startup.
Such a Zero Day exploit can affect Microsoft's Internet Explorer as soon as the web browser is launched for the first time. The exploit is also spreading on harmless SQL servers. Thus malware can also be distributed by providers who normally are regarded to be trustworthy.
Microsoft is aware of the problem and offers a detail list with workarounds. It contains tricks and tips for configuring the Internet Explorer to avoid the exploit. Even the upcoming Internet Explorer 8 is affected by the exploit, too, says heise.de.