VBS.Hart@mm

SUMMARY

This VBS worm spreads by sending itself to all addresses in the Microsoft Outlook address book. It also copies itself to all local or mapped network drives, and spreads through mIRC.

Protection

• Virus Definitions (LiveUpdate™ Weekly) March 27, 2002
• Virus Definitions (Intelligent Updater) March 22, 2002

Threat Assessment

Wild

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

Damage

• Damage Level: Low
• Large Scale E-mailing: The worm then sends itself to all address in the Outlook address book.

Distribution

• Distribution Level: High
• Subject of Email: One of the following: Britney Erotic Photos!!; This you phoros why this make; Hi My Friend !; Symantec New Update
• Name of Attachment: One of the following: Britney.pif; You_bad.pif; E-card.eml; Update_Symantec.pif
• Size of Attachment: 11,980 bytes
• Shared Drives: Copies itself to local and shared network drives.

TECHNICAL DETAILS

When the worm is executed, it does the following:

It creates the following files:

• C:WindowsE-card.eml
• C:WindowsE_card.zip
• C:WindowsBy-BR3AK-H3ART.vbs
• C:WindowsDystem32.dli
  
  NOTE: This is not a DLL file; the extension is actually DLI. That is, the second character of the extension is the letter "L" and the third character is the letter "i"
  
• C:Windowsdecode.dll
• C:WindowsBritney.pif
• C:WindowsYou_bad.pif
• C:WindowsUpdate_Symantec.pif
• C:Runwin.bat
• C:a.bat
• C:Ultima.vbs

The worm then adds the value:

system32            C:windowsy-BR3AK-H3ART.vbs

to the registry key:

HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun

Next, if it finds the Win.ini file, it adds the following line to it:

[windows]  
run=C:WINDOWSWScript.exe C:WINDOWSSYSTEM32.DlI

The worm then sends itself to all address in the Outlook address book. The email has the following characteristics:

Subject: The subject is one of the following:

• Britney Erotic Photos!!
• This you phoros why this make
• Hi My Friend !
• Symantec New Update

Message: The message is one of the following:

• Britney New Photo
• you bad :(
• This e-card for you
• New Update

Attachment: The attachment is one of the following:

• Britney.pif
• You_bad.pif
• E-card.eml
• Update_Symantec.pif

Next, it creates a Script.ini file in the Mirc folder that will use mIRC to spread the worm. Norton AntiVirus detects this Script.ini as VBS.Hart@mm.

Then the worm searches all local and network drives for .gif, .bmp, and .wav files.

• If it finds .gif or .bmp files, it copies itself to the same folder as the file that it finds, using the same name as found file, but with the .pif extension added to it. It then changes the original file attribute to hidden. For example, if it finds the file C:PicturesClouds.gif, it copies itself as C:PicturesClouds.gif.pif (which now has a Paint Brush icon) and changes the attribute of the C:PicturesClouds.gif file to hidden.
• If it finds .wav files, it copies itself to the same folder as the file that it finds, using the same name as found file, but with the .eml extension added to it. It then changes the original file attribute to hidden.

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

To remove this worm, delete files detected as VBS.Hart@mm, remove the value that it added to the registry, and delete the line that it added to the Win.ini file. Remove the hidden attribute from .gif, .bmp, and .wav files as needed.

To remove this worm:

1. Obtain the most recent virus definitions. There are two ways to do this:
   • Run LiveUpdate. LiveUpdate is the easiest way to obtain virus definitions. These virus definitions have undergone full quality assurance testing by Symantec Security Response and are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
   • Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions have undergone full quality assurance testing by Symantec Security Response. They are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.
     
     Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.
     
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. Write down the names of all files that are detected as VBS.Hart@mm and then click Delete for each one.
5. Using Windows Explorer, delete the following files if they exist:
   • C:Runwin.bat
   • C:A.bat
   • C:Ultima.vbs

To edit the registry:

CAUTION: We strongly recommend that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the keys that are specified. Read the document How to make a backup of the Windows registry for instructions.

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:
   
   HEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete the following value:
   
   system32            C:windowsy-BR3AK-H3ART.vbs
   
5. Click Registry, and click Exit.

To remove the entry from the Win.ini file:

NOTE: (For Windows Me users only) Due to the file-protection process in Windows Me, a backup copy of the file that you are about to edit exists in the C:WindowsRecent folder. We recommend that you delete this file before you continue with the steps in this section. To do this using Windows Explorer, go to C:WindowsRecent, and in the right pane select the Win.ini file and delete it. It will be regenerated as a copy of the file that you are about to edit when you save your changes to that file.

1. Click Start, and click Run.
2. Type the following, and then click OK.
   
   edit c:windowswin.ini
   
   The MS-DOS Editor opens.
   
   NOTE: If Windows is installed in a different location, make the appropriate path substitution.
   
3. In the [windows] section of the file, look for an entry similar to the following:
   
   run=C:WINDOWSWScript.exe C:WINDOWSSYSTEM32.DlI
   
4. Select the entire line. Be sure that you have not selected any other text, and then press Delete.
5. Click File, and click Save.
6. Click File, and click Exit.

To remove the hidden attributes:

1. Start Windows Explorer.
2. Click the View menu (Windows 95/98/NT) or the Tools menu (Windows Me/2000/XP), and then click Options or Folder options.
3. Click the View tab.
4. Uncheck "Hide file extensions for known file types."
5. Do one of the following:
   • Windows 95/NT. Click "Show all files."
   • Windows 98. In the Advanced settings box, under the "Hidden files" folder, click Show all files.
   • Windows Me/2000/XP. Uncheck "Hide protected operating system files" and under the "Hidden files" folder, click "Show hidden files and folders."
6. Click Apply, and then click OK.
7. Using Windows Explorer, locate each .gif, .bmp, and .wav files whose file name you wrote down when deleting the detected files.
8. For each one, right-click on the file and then click Properties.
9. Uncheck the Hidden attribute and then click OK.