Virus Profile: W97M/Trugbar.a

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Virus Profile information details
Risk Assessment: Home Low | Corporate Low
Date Discovered: 2/20/2004
Date Added: 2/20/2004
Origin: Unknown
Length: N/A
Type: Virus
Subtype: Macro
DAT Required: 4072
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

The presence of the file Trug.vbs in the hardcoded directory c:\Windows\System.  The autoexec.bat has been modified.

Methods of Infection

Opening an infected document will directly infect the local Word environment and any document opened thereafter.

Virus Characteristics

This threat is detected as W97M/Generic and contians one module - Trug. The virus disables the macro warning protection in Word and will also modify the registry key if day is  2nd or 18th day of the month

  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run", "SystemSettingÆ’ = "C:\Windows\TRUG.vbs"

It may disable commandbars and Visual Basic Editor will display the message:

On the 27th day of the month, it will delete the existing c:\autoexec.bat and replace it  with a modified version that will format the c: and d: drive. This file is detected as VBS/Trugbar.  On the 2nd or 18th of the month, the virus will drop the file TRUG.vbs into the hard coded directory c:\Windows\System . This vbs file attempts to overwrite all vxd, drv, inf, cab, zip, dat, com, exe and dll and adding the .vbs extension to these files. Due to bug in VBScript code, this does not happen. This file is detected as VBS/Trugbar.

Use current engine and DAT files for detection and removal.

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.

AVERT Recommended Updates:

* Office 2000 updates

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


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