W32.Atak@mm

SUMMARY

W32.Atak@mm is a mass-mailing worm that spreads by sending itself to email addresses gathered from the infected computer.

The email has the following characteristics:

Subject:

• Read the Result!
• Important Data!

Attachment:
A .zip file that includes a copy of the worm.

Protection

• Virus Definitions (LiveUpdate™ Weekly) July 14, 2004
• Virus Definitions (Intelligent Updater) July 14, 2004

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Low
• Large Scale E-mailing: Yes

Distribution

• Distribution Level: High
• Subject of Email: Read the Result! -or- Important Data!
• Name of Attachment: A .zip file containing a copy of the worm.
• Size of Attachment: 15,917 bytes

TECHNICAL DETAILS

When W32.Atak@mm is executed, it performs the following actions:

1. Copies itself as %System%hint.exe.
   
   Note: %System% is a variable. The worm locates the System folder and copies itself to that location. By default, this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
   
   
2. Creates a mutex named "SloperMtx" to ensure that only one instance of the worm is executed on the computer.
   
   
3. On Windows NT/2000/XP, the worm will add the value:
   
   "load"="%System%hint.exe"
   
   to the registry key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindows NTCurrentVersionWindows
   
   
4. On Windows 95/98/Me, the worm adds the following line to the [windows] section of Win.ini file:
   
   load=%System%hint.exe
   
   
5. Scans the following locations:
   
   
   • The default Windows address book
   • %Windir%Temporary Internet Files
   • Documents and Settings<user name>Local SettingsTemporary Internet Files
   • The A: drive
   • Drives C: to Z:, if the drive is a fixed or ram disk
     
     and attempts to get email addresses from files with the following extensions:
     
     
   • .txt
   • .eml
   • .nch
   • .mbx
   • .htm
   • .log
   • .ods
   • .mht
   • .sht
   • .php
   • .cgi
   • .asp
   • .jsp
   • .uin
   • .dbx
   • .msg
   • .vbs
   • .cfg
   • .xml
   • .html
   • .tbb
   • .adb
   • .pl
   • .wab
     
     
6. Sends itself out to email addresses is finds on the infected computer.
   
   The email has the following characteristics:
   
   From:
   Starts with one of the following strings:
   
   • kevin
   • huck
   • george
   • mike
   • andrew
     
     
     Subject:
   • Read the Result!
   • Important Data!
     
     Message:
     Authorized Researcher Only.
     
     Attachment:
   • A .zip file that includes a copy of the worm.
   • The .zip file name made up of three to seven random, lower-case characters.
   • The file name of the embedded file inside of the .zip file is made up of three to seven random, lower-case characters, with a .gif or .jpg extension, followed by 70 bland spaces, and then an .exe extension. For example: xan3f.gif .exe

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 following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Run a full system scan and delete all the files detected as W32.Atak@mm.
4. Delete the value that was added to the registry.
5. Edit the Win.ini file.
   

For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the aforementioned documents.


For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.

2. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:

• Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater).
  
  The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

3. To scan for and delete the infected files

1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan all files."
2. Run a full system scan.
3. If any files are detected as infected with W32.Atak@mm, click Delete.
   
   
   Note: If your Symantec antivirus product reports that it cannot delete an infected file, Windows may be using the file. To fix this, run the scan in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode." Once you have restarted in Safe mode, run the scan again.
   
   (After the files are deleted, you can leave the computer in Safe mode and proceed with section 4. When that is done, restart the computer in Normal mode.)
   

4. To delete the value from the registry

Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. Read the document, "How to make a backup of the Windows registry," for instructions.

1. Click Start > Run.
2. Type regedit
   
   Then click OK.
   
   
3. Navigate to the key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindows NTCurrentVersionWindows
   
   
4. In the right pane, delete the value:
   
   "load"="%System%hint.exe"
   
   
5. Exit the Registry Editor.

5. Edit the Win.ini file
If you are running Windows 95/98/Me, follow these steps:

1. The function you perform depends on your operating system:
   • Windows 95/98: Go to step B.
   • Windows Me: If you are running Windows Me, the Windows Me file-protection process may have made a backup copy of the Win.ini file that you need to edit. If this backup copy exists, it will be in the C:WindowsRecent folder. Symantec recommends that you delete this file before continuing with the steps in this section. To do this:
     1. Start Windows Explorer.
     2. Browse to and select the C:WindowsRecent folder.
     3. In the right pane, select the Win.ini file and delete it. The Win.ini file will be regenerated when you save your changes to it in step F.
        
        
2. Click Start > Run.
3. Type the following:
   
   edit c:windowswin.ini
   
   and then click OK.
   
   (The MS-DOS Editor opens.)
   
   NOTE: If Windows is installed in a different location, make the appropriate path substitution.
   
   
4. In the [windows] section of the file, look for a line similar to:
   
   load=%System%hint.exe
   
   
5. If this line exists, delete everything to the right of load=
   
   
6. Click File > Save.
7. Click File > Exit.