Threat Description



Category: Malware
Type: Worm
Platform: VBS
Aliases: San


San is a worm written in Visual Basic Script.


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More scanning & removal options

More information on scanning or removal options is available in the documentation for your F-Secure security product on the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

Contact Support

For further assistance, F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details


The worm arrives in an infected message sent with Outlook Express. When it is viewed, by opening it or via preview pane, it first drops "loveday14-a.hta" to the Windows Startup directory in both Spanish and English versions of Windows.

When the system is restarted, "loveday14-a.hta" will be executed. Also the worm creates an infected "index.html" file to the Windows System directory.

Next it uses registry to replace the default signature of Outlook Express 5 with the "index.html" created above.

On that way every time when an infected user send an email message, the worm will embed its html code to this message.

Next the worm replaces the Internet Explorer start page point to a web page, that contains another worm VBS/Valentine.A@mm. These two worms download each other.

If the system date is 8thy, 14th, 23rd or 29th on each month, then VBS/Sun.A will destroy the infected system. It will delete all directories and their contents from the drive "C:".

In the place of the original directories, the worm creates a folder with the same name adding a string "happysanvalentin". On that way a directory with a name "My Documents" will become "My Documentshappysavalentin".

This worm has been available on a public web page in the Internet and it has been posted to several Usenet newsgroups. Even after the infected web page has been removed from the Internet, the worm is able to spread via Outlook Express.

This worm uses the same security vulnerability as JS/Kak.A@m. A fix and futher information about this vulnerability is available from Microsoft:

Further information about JS/Kak.A@m is available at:

Technical Details:Katrin Tocheva and Sami Rautiainen, F-Secure; February 2000


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