CERT^® Incident Note IN-2001-15

Systems Affected

• Systems running Microsoft Windows with Microsoft Outlook installed
• Systems running Microsoft Windows with Microsoft Office and ICQ installed

Overview

W32/Goner is a malicious Windows program distributed as an email file attachment and via ICQ file transfers. To a user, the file (gone.scr) appears to be a Windows screen saver. W32/Goner infects a system when a user executes file "gone.scr".

Description

Late this morning, the CERT/CC began receiving reports of a new piece of malicious code known as W32/Goner. Since that time, the CERT/CC has received an increasing number of reports of this code circulating on the Internet.

Analysis indicates that this code is spreading via email with the following characteristics:

Subject:	Hi!

Body:	How are you ?
	When I saw this screen saver, I immediately thought about you
	I am in a harry, I promise you will love it!

Attachment:gone.scr

Several anti-virus vendors have stated that this code may also propogate via the ICQ messaging program. W32/Goner is believed to initiate a file transfer with any "online" users in the infected user's contact list. If the user on the receiving end approves the transfer, the worm sends a copy of itself.

When the file "gone.scr" is executed, the worm displays a splash screen and a false error message in an attempt to fool the user into thinking the program is a legitimate screen saver. It copies itself to the Windows system folder (usually C:\WINDOWS\SYSTEM32\scr.exe or C:\WINNT\SYSTEM32\scr.exe) and modifies the Windows registry to execute itself upon reboot by adding the following key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\ C:%WINDIR%\SYSTEM\gone.scr=C:\%WINDIR\SYSTEM\gone.scr

W32/Goner propagates by sending itself to all addresses listed in the Microsoft Outlook address book and all online users in the ICQ contacts list.

In addition, the worm looks for and terminates processes associated with many popular antivirus and security programs. The following processes/files are targeted by this malicious code:

APLICA32.EXE

ZONEALARM.EXE

ESAFE.EXE

CFIADMIN.EXE

CFIAUDIT.EXE

CFINET.EXE

PCFWallIcon.EXE

FRW.EXE

VSHWIN32.EXE

VSECOMR.EXE

WEBSCANX.EXE

AVCONSOL.EXE

VSSTAT.EXE

PW32.EXE

VW32.EXE

VP32.EXE

VPCC.EXE

VPM.EXE

_AVP32.EXE

_AVPCC.EXE

_AVPM.EXE

AVP32.EXE

AVPCC.EXE

AVPM.EXE

AVP.EXE

LOCKDOWN2000.EXE

ICLOAD95.EXE

ICMON.EXE

ICSUPP95.EXE

ICLOADNT.EXE

ICSUPPNT.EXE

TDS2-98.EXE

TDS2-NT.EXE

FEWEB.EXE

SAFEWEB.EXE

If W32/Goner finds any of these programs running, the process is terminated and all files in the directory containing that executable are deleted. If the worm is unable to delete the files immediately, it creates a file called WININIT.INI, which deletes the files upon reboot.

There is also some evidence that W32/Goner may install denial of service scripts for the mIRC Internet Relay Chat client.

Impact

The worm may disable anti-virus and security software installed on the system.

During propagation, sites may experience residual denial of service conditions on hosts or email systems through which the worm is sent.

Solutions

Run and maintain an antivirus product

Appendix A. Vendor Information

Antivirus Vendor Information

Computer Associates