W97M/Nono.A

This page shows details and results of our analysis on the malware W97M/Nono.A

Download Current DAT: 6712

Threat Detail

Malware Type: Virus

Malware Sub-type: Macro

Discovery Date: 1998-12-08

Next Steps:

Overview
Characteristics
Symptoms
Method of Infection
Removal

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

5.1.00

File Length

Description Added

1999-03-23

Description Modified

1999-03-23

Malware Proliferation

Characteristics

This is a macro virus for Word97 documents and templates. This virus will infect systems evan after updating to SR1 update and above. This virus includes technique of the W97M/Class virus by use of a temp file for module insertion between virus and host file.

This virus contains 2 macro modules and 1 class module. This virus exports code to 2 files in the root of C: - v1.bas and (user initials) (i.e. if user initials are JB, the file exported is "c:\jb." Both files contain source code of the virus.

Replication works using auto and system macros. The code within the class module occupying the first Visual Basic project normally named "ThisDocument" contains code only to replicate to other documents based on the Word event of opening documents. The subroutine within this code is named "Autoopen" in order to hook the event.

This virus has a time and date activated message box payload however no other damage is performed against the hard drive.

Symptoms

Macro warning when opening infected documents on non-infected system, existence of source code files as described above.

During opening of infected documents, if the time within the hour is 30 minutes and 16 seconds, and if today is the 10th of any month, a question message box is shown:

--------------
Hard.Poppy
Run Animation?
[Yes] [No]
--------------

Either choice exits the question box uneventful.

Method of Infection

Opening infected documents on non-infected systems will directly infect the global template 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:

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.