W97M/Melissa.ao@mm

This page shows details and results of our analysis on the malware W97M/Melissa.ao@mm

Download Current DAT: 6712

Threat Detail

Malware Type: Virus

Malware Sub-type: Macro

Discovery Date: 2000-03-08

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

4069 (2000-03-15)

Updated DAT

4389 (2004-09-01)

Minimum Engine

5.1.00

File Length

Description Added

2000-03-16

Description Modified

2002-09-18

Malware Proliferation

Characteristics

This is a class module macro virus for Word97 documents and templates. This virus will infect systems even after updating to SR1 update and above. This virus will disable the macro warning settings if the macro is allowed to run. This virus uses MAPI email propagation which is typical of this virus family.

This virus renames the first VB project in a document's macro storage from "ThisDocument" to "Worm_Empire" during virus infection. This virus will modify the registry after it has performed its email routine basically as a note to itself that it has already performed this payload. The setting is:

HKLM\Security
ActiveWorm="Worm Empire"

This virus may arrive via Outlook email as an attachment to a message from someone you know. The message format looks like this:

Subject:"Extremely URGENT: To All E-Mail User - (Date)"
Body:"This announcement is for all E-MAIL user. Please take note that our E-Mail Server will down and we recommended you to read the document which attached with this E-Mail."

Users should delete messages which match this description.

Symptoms

Registry modification as mentioned above, email propagation as mentioned above.

This virus has a date activated routine which activates on the 10th of the month and within the 10th hour of the day. The virus will save the active document 5 times in the working folder and inserts this line at the top of that document in large italics:

"Worm! Let's We Enjoy."

Method of Infection

This virus may arrive via Outlook email as an attachment. If run and the macros are allowed to run, the virus will infect the global template and any document used thereafter. The virus hooks Word events of opening and closing documents in an effort to maximize the chance of spreading to new host documents or templates.

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.