WM/NOMVIR.A;B

This page shows details and results of our analysis on the malware WM/NOMVIR.A;B

Overview

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.


Minimum DAT

4002 (1998-12-02)

Updated DAT

4002 (1998-12-02)

Minimum Engine

5400.1158

File Length

Not Applicable

Description Added

1997-04-15

Description Modified

2002-09-18

Malware Proliferation

Characteristics

This virus propagates by infecting Word Documents in Microsoft WORD Versions 6.x / 7.x on Windows and Macintosh platforms. The virus consists of these macros:

AUTOEXEC, AUTONEW, AUTOOPEN, DATEISPEICHERN, DATEISPEICHERNUNTER, DATEIBEENDEN, EXTRASMAKRO, DATEIDOKVORLAGEN, FUCKIT, DATEIDRUCKEN

in an infected document. The virus becomes active by using Auto- and SystemMacros. Its spreading activity remains only in the german language version of Microsoft Word. However, the virus may be able to execute its payload in another language version. All macros are encrypted using the standard Word execute-only feature. Meaning that the user is unable to edit or view the macro code.

Symptoms

On an infected system the virus hides the FILE|TEMPLATE and TOOLS|MACRO functionality. Warning: It is important not to use this command, as you will execute the viral code.

The virus maintains a Win.INI entry: INTL|ICOUNT = to count the number of times a document is printed. The virus also maintains a Win.INI entry: COMPATIBILITY|NOMVIR = for debug purposes.

When exiting Word there is a 1-in-6 chance that the macro will set the FILE|SAVEAS password to 'gATes?' (where ? is one randomly calculated letter). If you are affected please read "Add. Information".

When saving a document and the counter is equal to 10 or 20 it will delete the files C:\AUTOEXEC.BAT and C:\CONFIG.SYS .

When saving a document on an even numbered day after 9PM it will insert the text

'F*** Microsoft & Bill Gates'c at the end of the document.

On every 23rd / December 25th / January 1st or Friday 13th it will delete the files

User.da0, Systemda0, User.dat and System.dat in the C:\WINDOWS directory on Windows95.

Method of Infection

Removal

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:

SCANPM /ADL /CLEAN /ALL

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.

Variants

WM/NOMVIR.A
WM/NOMVIR.B
NOMVIR.B