W97M/Melissa.v

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

Download Current DAT: 6712

Threat Detail

Malware Type: Virus

Malware Sub-type: Macro

Discovery Date: 1999-10-11

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

4049 (1999-10-27)

Updated DAT

4049 (1999-10-27)

Minimum Engine

5.1.00

File Length

Description Added

1999-10-12

Description Modified

1999-10-12

Malware Proliferation

Characteristics

This virus uses a single macro module named "MP" and infects the normal template when opening an infected document.

In Word2000, the macro security level is set to the lowest setting, allowing macros to run. The infected document checks for a value in the registry at the location "HKCU\Software\Microsoft\Office\" with a key of "mp?" and a value of "... by 22". If this does not exist, Outlook is started and an email message is created with the subject line "My Pictures" and the Word97 or Word2000 registered user name (i.e. John Doe). The infected document is attached and no message body is given - this email is sent to the first 40 recipients in the available address book, which can include distribution lists. After sending the email message, the registry is modified with the value above.

This virus also has a payload. After the infection routine, it then attempts to delete files and directories in the root of mapped drives with the following letters sequentially in this order: "M:\", "N:\", "O:\", "P:\", "Q:\", "S:\", "F:\", "I:\", "X:\", "Z:\", "H:\", "L:\". The virus is not subtle in announcing itself; a messagebox is shown with this message: "Please Check Your OutLook Inbox E-Mail !". After pressing 'OK' button, text is then inserted into the open document with the content: "Hint: Get Norton 2000 not McAfee 4.02".

This virus can be detected by VirusScan engine v4.0.35 and DAT files of at least 4020 when using heuristic scanning method as "virus or variant of W97M/Melissa.gen".

Symptoms

Macro warning if opening infected document, increase in size to global template, confirmation of changes to NORMAL.DOT. Users mention receipt or send of an email message as described above.

Method of Infection

Opening infected documents will infect global template normal.dot.

EXTRA Drivers
VirusScan 4 with the 4.0.25 engine (and above).
Dr. Solomon's AVTK 7.95 and above

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.