Welcome to the Virus Encyclopedia of Panda Security.
It drops the Elkern.A virus, prevents the computer from starting up correctly and renders infected files unusable.
Klez.F is a worm that reaches computers in an e-mail message.
It is very easy to become infected by this worm, as it is automatically activated when the message is viewed through Outlook’s Preview Pane. It does this by exploiting a vulnerability in Internet Explorer (versions 5.01 and 5.5), which allows files attached to e-mail messages to be automatically run.
The dangers of Klez.F are the following:
Klez.F is difficult to recognize because it is hidden in e-mail messages with variable characteristics. The most common subjects are:
For more information consult the section Means of transmission.