Threat Description



Category: Malware
Type: Virus
Platform: W32
Aliases: Dementia


This is an unusual virus. It infects COM and EXE files normally, but is also able to infect ZIP files: virus inserts a file called CALLFAST.COM to any ZIP file when they are accessed. This file is a BBS advertisment for 'Dementia BBS' and is infected by the virus.

It seems that the virus has been written to faciliate stealing files from a BBS system. Virus checks any ZIP file for a file called REQUEST.IVA. If such a file is found, virus reads a filename list from this file, collects the files, encrypts them and adds them to the same ZIP file as file RECEIPT.IVA.

Dementia does not need external programs to modify ZIP files.

Dementia contains these texts:

Dementia         Copyright 1993 Necrosoft enterprises  -  All rights reserved         I am the man that walks alone         And when I'm walking a dark road         At night or strolling through the park         When the light begins to change         I sometimes feel a little strange         A little anxious when it's dark  


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.

Description Details: Mikko Hypponen, F-Secure


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