Threat Description



Category: Malware
Platform: W32
Aliases: ATU


The viruses of this family use an uncommon way of spreading. Instead of copying their macro program to the macro area in victim documents, they just write to documents a reference to a template (attached template) which contains virus macros. MS Word97 when opening a such document detects the reference to the attached template, opens it and executes its macros. The virus macro gets control and runs infected procedure. As a result the infected documents have no macro code, but on their opening the virus macro code is loaded by Word97 and executed.


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

In the known versions of this virus the reference to attached template points to a file on a remote Internet site (virus-writers Web site). As a result, MS Word97 on opening an affected document downloads and processes the template that is placed in the Internet zone. Because of that virus author(s) are able to "upgrade" virus code by replacing the template on their Web site.

This way of spreading allows the virus to bypass the anti-virus protection (VirusWarning) in old versions of MS Word97. These Word97 versions have a security breach: the anti-virus protection is not activated by Word97 to scan attached templates for macro code. This bug in MS Word97 was fixed in the beginning of 1999.

This variant contains this comment:

         Active Template Update  

Variant: ATU.B

This virus version does not copy entire code from the template to global macros area, but only the code necessary to infects documents.

This variant contains this comment:

         Active Template Update v0.2 /1nternal  

Technical Details:Eugene Kaspersky


Suspect a file or URL was wrongly detected? Submit a sample to our Labs for analysis

Submit Now

Give And Get Advice

Give advice. Get advice. Share the knowledge on our free discussion forum.

Learn More