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Panda Protection

Virus Encyclopedia

Welcome to the Virus Encyclopedia of Panda Security.

Encyclopedia GetVirusCard True 0

Klez.H

 
Threat LevelModerate threatDamageHighDistributionNot widespread
Common name:Klez.H
Technical name:W32/Klez.H
Threat level:Low
Alias:Klez.K,, Klez.gen@MM, W32/Klez.K-mm, WORM_KLEZ, Klez.G, W32/Klez.G-mm
Type:Worm
Effects:  It overwrites executable files and modifies some system controllers, preventing the affected computer from starting up correctly.

Affected platforms:

Windows XP/2000/NT/ME/98/95

Detection updated on:Oct. 31, 2007
StatisticsNo
Family:KLEZ

Brief Description 

    

Klez.H is a worm that reaches computers in an e-mail message, which is difficult to recognize as its subject varies. The most common subjects however, are How are you? or let’s be friends.

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 also carries out its infection when the file attached to the message is run.

The effects of Klez.H are the following:

  • It automatically and rapidly spreads to all the contacts in Outlook’s Address Book.
  • It overwrites  executable files, rendering them unusable.
  • It deactivates processes that are running.
  • It attempts to delete files corresponding to antivirus programs.

Visible Symptoms 

    

Klez.H is difficult to recognize as it reaches computers hidden in an e-mail message with variable characteristics. The most common subjects are:

How are you?
let’s be friends
Darling
So cool a flash,enjoy it
Your password
honey

For more information consult the section Means of transmission.