Threat Description

Compat

Details

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

Summary


XM/Compat.A is a polymorphic macro virus. The virus changes its appearance so it looks different in every infected file. This is done by inserting random comments into the virus code.



Removal


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 virus consists of 11 subroutines: Auto_Open, Auto_Close, Auto_Exit, Auto_Help, Macro1, Macro2, Macro3, Macro4, Macro5, Macro6, and Macro7. They are in one module which has polymorphic name.

The virus puts the following comment in the beginning of its code:

 Macro recorded (month)/(day)/(year) by (user)   

The variables (month), (day), (year) and (user) are different for every environment and replication. The virus saves its code in different files and paths depending on the environment.

On Macintosh, the files are "Office 97 Compatibility" and "MS Excel Visual Basic Example", but on Windows 95 they are "Off97com.xla" and "Vba_xl.txt".

The virus builds its code as Add-In in Off97com.xla file. Compat works only in Excel 95. It does not infect Excel 97.

Compat has a payload which activates after 31 August 1998. After that date, the virus modifies the contents of random cells by changing the values slightly. This can have disasterous effects.






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