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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.

Aliases

• VBS/Verlor

• Verlor.a

• W97M.Overlord

• W97M/Verlor.gen

Characteristics

This virus propagates by infecting Word documents in Microsoft Word 97 and 2000. This virus consists of a module called `Module'. It will turn off the macro warning feature of Word 97. This macro virus will always infect Word's NORMAL.DOT file. If a document is opened its name is appended to C:\HIMEM.SYS. The virus infects documents when they are closed. After infecting a document its name is removed from C:\HIMEM.SYS.

W97M/Verlor is a stealth virus; it will not just attempt to intercept the macro viewing commands to attempt to hide its presence but it also features advanced stealth mechanisms described below.

If a user opens Word's Visual Basic-Editor (VBE) the virus first sets the following registry value:

HKLM\software\RegisteredOwner = "the Overlord"

It then searches the file WIN.INI for a [windows] section. If this section is found W97M/Verlor adds the entry

run = %WINDIR%\overlord.b.vbs [%WINDIR% = name of Windows directory]

to the [windows] section in WIN.INI and drops two files to the Windows directory:
- OVERLORD.B.VBS containing a Visual Basic Script (VBScript)
- OVERLORD.B.DLL containing the virus source code as ASCII text

The virus then deletes itself from all open documents and Word's NORMAL.DOT in order to hide its presence and displays the Visual Basic-Editor. If the Windows Scripting Host (WSH) is installed, the script OVERLORD.B.VBS is executed during the next Windows start-up. The main task of this script is to re-infect Word's NORMAL.DOT using the virus source code stored in OVERLORD.B.DLL. Additionally, all documents noted in C:\HIMEM.SYS are opened and saved without any modification.

W97M/Verlor also intercepts the macro viewing command TOOLS | MACRO | MACROS. Before the dialog is displayed the virus removes all macros from all open documents and NORMAL.DOT. When the user closes the dialog later the virus writes its code back to all open documents and NORMAL.DOT.

Symptoms

Presence of files OVERLORD.B.VBS and OVERLORD.B.DLL in Windows directory, modification of file C:\HIMEM.SYS. Registry key HKLM\software\RegisteredOwner set to value "the Overlord".

Method of Infection

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

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:

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

Variants

N/A

All Information

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.

Aliases

• VBS/Verlor

• Verlor.a

• W97M.Overlord

• W97M/Verlor.gen

Characteristics

Characteristics -

This virus propagates by infecting Word documents in Microsoft Word 97 and 2000. This virus consists of a module called `Module'. It will turn off the macro warning feature of Word 97. This macro virus will always infect Word's NORMAL.DOT file. If a document is opened its name is appended to C:\HIMEM.SYS. The virus infects documents when they are closed. After infecting a document its name is removed from C:\HIMEM.SYS.

W97M/Verlor is a stealth virus; it will not just attempt to intercept the macro viewing commands to attempt to hide its presence but it also features advanced stealth mechanisms described below.

If a user opens Word's Visual Basic-Editor (VBE) the virus first sets the following registry value:

HKLM\software\RegisteredOwner = "the Overlord"

It then searches the file WIN.INI for a [windows] section. If this section is found W97M/Verlor adds the entry

run = %WINDIR%\overlord.b.vbs [%WINDIR% = name of Windows directory]

to the [windows] section in WIN.INI and drops two files to the Windows directory:
- OVERLORD.B.VBS containing a Visual Basic Script (VBScript)
- OVERLORD.B.DLL containing the virus source code as ASCII text

The virus then deletes itself from all open documents and Word's NORMAL.DOT in order to hide its presence and displays the Visual Basic-Editor. If the Windows Scripting Host (WSH) is installed, the script OVERLORD.B.VBS is executed during the next Windows start-up. The main task of this script is to re-infect Word's NORMAL.DOT using the virus source code stored in OVERLORD.B.DLL. Additionally, all documents noted in C:\HIMEM.SYS are opened and saved without any modification.

W97M/Verlor also intercepts the macro viewing command TOOLS | MACRO | MACROS. Before the dialog is displayed the virus removes all macros from all open documents and NORMAL.DOT. When the user closes the dialog later the virus writes its code back to all open documents and NORMAL.DOT.

Symptoms

Symptoms -

Presence of files OVERLORD.B.VBS and OVERLORD.B.DLL in Windows directory, modification of file C:\HIMEM.SYS. Registry key HKLM\software\RegisteredOwner set to value "the Overlord".

Method of Infection

Method of Infection -

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

Removal -

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:

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

Variants -

N/A