Virus Profile: W97M/BackHand.A

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Virus Profile information details
Risk Assessment: Home Low | Corporate Low
Date Discovered: 12/30/1999
Date Added: 12/30/1999
Origin: N/A
Length: N/A
Type: Virus
Subtype: Macro
DAT Required: 4057
Removal Instructions


This is a virus detection. Viruses are programs that self-replicate recursively, meaning that infected systems spread the virus to other systems, which then propagate the virus further. While many viruses contain a destructive payload, it's quite common for viruses to do nothing more than spread from one system to another.

Indication of Infection

Existence of file sysboot.bin as mentioned above, message boxes as mentioned above.

Methods of Infection

Opening infected documents will directly infect the local Word environment and any document used thereafter.



Virus Characteristics

This is a class module virus for Word 97 documents. It is able to replicate in the SR-1 and above releases of Word 97. It will turn off the macro warning feature of Word 97. This virus consists of a single module within the class stream named "ThisDocument". This virus creates a temporary text file which contains the virus code in a file named "C:\sysboot.bin".

This virus has three date activated payloads.

First, if the current day of the month is the 13th, the active document and any document used will be saved with a random 10 digit numeric password. And if the day of the week is Friday, it will display a message box with this text:

"It's Friday 13th! This is my lucky day, I hope it's yours too!"
"Have A Nice Day!"

If the day is not Friday but the date is the 13th, a message box is displayed with this text:

"Your document has been corrupted because of a bug in Word! Call Microsoft Customer Support, they can help you. When you call, tell them this Bug-ID Code (don't forget it!): " (followed by actual password used to protect the document)

After January 1, 2000, the system date is immediately reset to 01/01/80. (Note: The password payload then happens 13 days later.)

All Users :
Script,Batch,Macro and non memory-resident:
Use current engine and DAT files for detection and removal.

PE,Trojan,Internet Worm and memory resident :
Use specified engine and DAT files for detection. To remove, boot to MS-DOS mode or use a boot diskette and use the command line scanner:


Additional Windows ME/XP removal considerations

Users should not trust file icons, particularly when receiving files from others via P2P clients, IRC, email or other mediums where users can share files.

AVERT Recommended Updates :

* Office2000 Updates

* Malformed Word Document Could Enable Macro to Run Automatically (Information/Patch )

* scriptlet.typelib/Eyedog vulnerability patch

* Outlook as an email attachment security update

* Exchange 5.5 post SP3 Information Store Patch 5.5.2652.42 - this patch corrects detection issues with GroupShield

For a list of attachments blocked by the Outlook patch and a general FAQ, visit this link .
Additionally, Network Administrators can configure this update using an available tool - visit this link for more information .

It is very common for macro viruses to disable options within Office applications for example in Word, the macro protection warning commonly is disabled. After cleaning macro viruses, ensure that your previously set options are again enabled.


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