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Virus Encyclopedia

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Threat LevelModerate threatDamageHighDistributionNot widespread
Common name:Happy
Technical name:W32/Happy
Threat level:Low
Alias:Happy99,, I-Worm.Happy,Trojan.Happy99, W32/Ska-Hapyy99, Ska, Ska.exe, W32/Ska.A, W32/Ska.A-m, PE_SKA, Wsock
Effects:  It has no destructive effects, but displays fireworks graphics on the screen. Mass-mailing this worm might flood e-mail accounts.

Affected platforms:

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

First detected on:Jan. 28, 1999
Detection updated on:Sept. 21, 2009
Proactive protection:
Yes, using TruPrevent Technologies
Repair utility:Panda QuickRemover

Brief Description 


Happy is a worm that arrives in an e-mail message with the subject Happy New Year 1999!! and the following attachment: HAPPY99.EXE.

The text included in the message entices users to open the attachment, by trying to convince them it is just a greeting card.

Happy is not considered dangerous, as its only objective is to spread to other computers without causing any destructive effects.

It is capable of spreading at great speed, as all the actions it carries out at aimed at propagating to other computers by e-mail.

Visible Symptoms 


A clear indication that you have received Happy is an e-mail message with the following characteristics:

  • Subject:
    Happy New Year 1999 !!
  • Attachments:

Upon running the attachment a window is displayed, which seems to simulate a fireworks display to celebrate the New Year: