Virus Profile: W97M/Mck.e

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Virus Profile information details
Risk Assessment: Home Low | Corporate Low
Date Discovered: 11/12/1999
Date Added: 11/15/1999
Origin: N/A
Length: N/A
Type: Virus
Subtype: Macro
DAT Required: 4054
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

Macro warning if opening infected document, increase in size to global template. Entire document "deletion" as listed above.

Methods of Infection

Opening infected documents will infect global template - on pre-SR1 installations documents used within Word97 after global template is infected will also be infected.

Virus Characteristics

This is a virus for Word 97 documents. It is not able to replicate under the SR-1 release of Word 97. It will turn off the macro warning feature of Word 97. This virus consists of a module called "Halimaw". It is created using a virus creation kit and is polymorphic.

This virus hooks the system event of opening Word97 by the subroutine "autoexec" thereby running its code. Other system events hooked are "autoopen", "autonew", "filesave", "filesaveas" and "fileclose". Attempts to use menu items of the same name within Word97 will run the macro code routine.

When opening an infected document and allowing the macro virus to run, if the minutes of the hour are between 1 and 30, a payload routine removes the text of the entire document by using the "SELECTALL/CUT" method. This means the document is still in the "clipboard" and can be retrieved by using either the menu "EDIT/PASTE" or CTRL-V keyboard shortcut.

Document properties are modified with the following values:
Author = "Lucky Warrior"
Keywords = "W97M/Halimaw"
Comments = "Anti Government Corrupt Officials"

On the 20th of the month, this virus attempts to delete files and folders by issuing a "deltree" command in a shell of MS-DOS.

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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