W32.Goner.A@mm

SUMMARY

Due to a decreased number of submissions, Symantec Security Response is downgrading W32.Goner.A@mm from a threat rating of Category 3 to Category 2.

W32.Goner.A@mm is a mass-mailing worm that is written in Visual Basic. The worm has been compressed using a Portable Executable (PE) file compressor. The worm can spread its infection using the ICQ network as well as by email using Microsoft Outlook. If IRC is installed, this worm can also insert mIRC scripts that will enable the computer to be used in Denial of Service (DOS) attacks. The IRC channel used for controlling the worm is currently blocked, preventing this functionality.

Behavior

Symptoms

Transmission

Protection

• Virus Definitions (LiveUpdate™ Weekly) December 4, 2001
• Virus Definitions (Intelligent Updater) December 4, 2001

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: More than 1000
• Number of Sites: More than 10
• Geographical Distribution: High
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Medium
• Payload: Upon execution
• Large Scale E-mailing: Send itself to all users in Outlook Address Books
• Deletes Files: Attempts to delete antivirus and firewall software

Distribution

• Distribution Level: High
• Subject of Email: Hi
• Name of Attachment: Gone.scr
• Size of Attachment: 38,912 bytes

TECHNICAL DETAILS

This attachment will not be executed by viewing the message in the preview pane. The attachment must be executed to begin delivering its payload. Upon execution, W32.Goner.A@mm starts by displaying the following window.



In the background, the worm sends itself to all addresses in the the Microsoft Outlook address book. The email appears as follows.



The worm has been packed using a known Portable Executable (PE) packer. The size of the unpacked worm is approximately 159 KB.

The worm adds the value

C:\%SYSTEM%gone.scr C:\%SYSTEM%gone.scr

to the registry key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun

NOTES:

• %SYSTEM% is the path to the Windows System folder. In most cases this would be C:WindowsSystem; however, the location could be different if the Windows System folder has been installed to a different location.
• The value is the same as the value as the name of the file (the value data) that is being called.

Once the registry key has been added, the worm will attempt to terminate the processes of common anti-virus and firewall products. The files that it attempts to terminat are as follows:

• Aplica32.exe
• Avconsol.exe
• Avp.exe
• Avp32.exe
• Avpcc.exe
• Avpm.exe
• Cfiadmin.exe
• Cfiaudit.exe
• Cfinet32.exe
• Esafe.exe
• Frw.exe
• Icload95.exe
• Icloadnt.exe
• Icmon.exe
• Icsupp95.exe
• Icsuppnt.exe
• Lockdown2000.exe
• Navapw32.exe
• Navw32.exe
• Pcfwallicon.exe
• Safeweb.exe
• Tds2-98.exe
• Tds2-Nt.exe
• Vsecomr.exe
• Vshwin32.exe
• Vsstat.exe
• Webscanx.exe
• Zonealarm.exe
• _Avp32.exe
• _Avpcc.exe
• _Avpm.exe

NOTE: Some anti-virus vendors have reported that the file iamapp.exe will have its process terminated. This is not correct.. Symantec Security Response has verified that the iamapp.exe process is not terminated by Goner, nor is the file deleted.

If such a process is found, the worm will delete the executable file and all files contained within the same folder and subfolders where the given file resides. If the files are in use and cannot be deleted, the file %SYSTEM%Wininit.ini is created, and is used to delete the files when the computer restarts.

NOTE: On Windows NT/2000/XP computers, the files are deleted by using the following registry key:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession Manager

where the files to be deleted are present in the value

PendingFileRenameOperations


W32.Goner.A@mm is capable of spreading over the ICQ network. If ICQ is installed on an infected computer, the worm will do the following:

1. Check for the version of the ICQ .dll file that contains the APIs that will be used. If the correct version is found, the worm proceeds.
2. Retrieve a list of all "buddies" who are currently online.
3. Retrieve information about each user individually. This information is required to be able to send files.
4. Send itself to all users on the list.

If mIRC is installed, this worm can insert scripts into the mIRC folder. This allows the computer to be used in DoS attacks. Currently, the IRC channel used for controlling the worm has been blocked by IRC Operators. This will prevent usage of infected systems in a DoS attack.

Finally, the worm displays the following fake error message:

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.

REMOVAL

The preferred way to remove this worm is to use the removal tool. If that is not an option in your situation, you must remove the worm manually.

Removal Tool
Symantec Security Response has posted a removal tool to assist in eradicating this worm. Please go to the following Web site to read the instructions and download the removal tool:

http://securityresponse.symantec.com/avcenter/venc/data/w32.goner.a@mm.removal.tool.html


Manual Removal

An online tutorial on how to manually remove W32.Goner.A@mm is available here.

To manually remove this worm, you must restart the computer in Safe mode or end the process on the part of the worm that is running in memory. Then reverse the changes that the worm made to the registry, restart the computer, reinstall Norton AntiVirus, and then run a full system scan and delete all infected files. Detailed instructions follow.

Follow the instructions for your version of Windows.

Windows 95/98/Me
Because the worm file may be in use, you must restart in Safe mode to remove the changes made to the registry.

CAUTION: (For Windows Me users only.) If you are running Windows Me, follow the instructions in the section System Restore option in Windows Me at the end of this document before you begin the removal procedure.

Restart the computer in Safe mode by following the instructions in How to restart Windows 9x or Windows Me in Safe mode.

NOTE: Shut down the computer for a full 30 seconds before restarting in Safe Mode to make sure the worm has been cleared from memory.

Windows NT/2000/XP
Because the worm file may be in use, you must End Process on the worm files before the registry value can be removed.

1. Press Ctrl+Alt+Delete one time.
2. Click Task Manager.
3. Click the Processes tab.
4. Click the "Image Name" column header two times to sort the processes alphabetically.
5. Scroll through the list and look for gone.scr. If you find the file, click it and then click End Process.
6. Scroll through the list and look for pentagone. If you find the file, click it and then click End Process.
7. Close the Task Manager.

Edit the registry

CAUTION: We strongly recommend that you back up the system registry before you make any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Please make sure that you modify only the keys that are specified. Please see the document How to back up the Windows registry before you proceed.

1. Click Start, and click Run. The Run dialog box appears.
2. Type regedit and then click OK. The Registry Editor opens.
3. Navigate to the following key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete the following value:
   
   C:\%SYSTEM%gone.scr C:\%SYSTEM%gone.scr
   
   NOTE: %SYSTEM% is the path to the Windows System folder. In most cases this would be C:WindowsSystem; however, the location could be different if the Windows System folder has been installed to a different location.
   
5. Click Registry, and click Exit.
6. Restart the computer.
7. Reinstall NAV, and restart the computer.

Remove the worm files

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
   
   CAUTION: If the worm has successfully deleted the target Norton AntiVirus files, you must uninstall and then reinstall Norton AntiVirus before you can run LiveUpdate or remove the worm using Norton AntiVirus. If Norton AntiVirus was installed as part of another Symantec program, such as System Works or Norton Internet Security, you must uninstall and reinstall those as well. Read the instructions in the section How to uninstall and reinstall your Symantec software before you continue.When finished, return to this section and complete the removal procedure.
   
2. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
3. Run a full system scan.
4. Delete all files that are detected as W32.Goner.A@mm. Deleted files must be either replaced from a clean backup or reinstalled.

Reinstall your firewall product, if needed.