Infostealer.Rimd

SUMMARY

Infostealer.Rimd is a password-stealing Trojan Horse that attempts to steal information from a Chinese online game. This Trojan Horse then sends the information to the author of the Trojan.

NOTE : Definitions prior to May 10, 2006 may detect this threat as PWSteal.Rimd

Protection

• Virus Definitions (LiveUpdate™ Weekly) December 31, 2002
• Virus Definitions (Intelligent Updater) December 31, 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: Medium
• Releases Confidential Info: Steals information related to an online Chinese game.

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

When Infostealer.Rimd is executed, it attempts to do the following:

1. Creates the following files:
   • %System%Hahaha.dll
   • %Windir%Kernel.exe
     
     NOTES:
     • %Windir% is a variable. The Trojan locates the Windows installation folder (by default, this is C:Windows or C:Winnt) and copies itself to that particular location.
     • %System% is a variable. The Trojan locates the System folder and copies itself to that particular location. By default, this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
       
2. Modifies the (Default) value of the registry key
   
   HKEY_LOCAL_MACHINESoftwareClassesexefileshellopencommand
   
   to
   
   %windir%kernel.exe "%1" %
   
   This causes the Trojan to be executed each time an executable file is run.
   
3. Finally, the newly inserted .dll, Hahaha.dll, will be executed. This file will hook the mouse and keyboard so that a function in Hahaha.dll will be called when the mouse or keyboard is used. The function called in Hahaha.dll attempts to find a window that belongs to a Chinese online game. If found, it will save the account information from this window within the file %Windir%kernel.ini. The Trojan Horse will then email Kernel.ini to the author of the Trojan.

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

These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines. If the variant Trojan has already executed, you will not be able to start most programs, including the Symantec antivirus software or LiveUpdate.

• If you cannot start most programs, follow all the instructions in the order shown in the following list.
• If you are able to start the programs, skip step 1.

1. Copy Regedit.exe to Regedit.com.
2. Reverse the changes made to the registry.
3. Run a full system scan and delete all the files detected as Infostealer.Rimd.
4. Edit the Windows registry.

For further details, read the following instructions.

Copying Regedit.exe to Regedit.com
Because the worm modified the registry so that you cannot run the .exe files, first make a copy of the Registry Editor as a file with the .com extension, then run the file.

1. Do one of the following, depending on which version of Windows you are running:
   • Windows 95/98 users:
     1. Click Start.
     2. Point to Programs.
     3. Click the MS-DOS Prompt (A DOS window opens at the C:Windows prompt.). Proceed to step 2 of this section.
   • Windows Me users:
     1. Click Start.
     2. Point to Programs.
     3. Point to Accessories.
     4. Click the MS-DOS Prompt (A DOS window opens at the C:Windows prompt.). Proceed to step 2 of this section.
   • Windows NT/2000 users:
     1. Click Start, then click Run.
     2. Type command, then press Enter. (A DOS window opens.)
     3. Type cd winnt, then press Enter.
     4. Go to step 2 of this section.
   • Windows XP users:
     1. Click Start, then click Run.
     2. Type command, then press Enter. (A DOS window opens.)
     3. Type the following:
        
        cd
        cd windows
        
        Then press Enter after typing each one.
        
     4. Proceed to step 2 of this section.
        
2. Type copy regedit.exe regedit.com, then press Enter.
   
3. Type start regedit.com, then press Enter. (The Registry Editor will open in front of the DOS window.)
   
   After you finish editing the registry, exit the Registry Editor, and then exit the DOS window as well.
   
   Proceed to the section, "Editing the registry and removing keys and changes made by the Trojan," only after you have performed the previous steps.
   
   (The Registry Editor will open in front of the DOS window.) After you finish editing the registry and have closed the Registry Editor, close the DOS window as well.

Editing the registry and reversing the changes made by the Trojan

Symantec strongly recommends 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 the specified keys only. For instructions, read the document, "How to make a backup of the Windows registry."

1. Navigate to and select the following key:
   
   HKEY_LOCAL_MACHINESoftwareClassesexefileshellopencommand
   
   NOTE: The HKEY_LOCAL_MACHINESoftwareClasses key contains many subkey entries that refer to other file extensions. One of these file extensions is .exe. Changing this extension can prevent any files ending with an .exe extension from running. Make sure that you browse all the way along this path until you reach the command subkey.
   
   Modify the HKEY_LOCAL_MACHINESoftwareClassesexefileshellopencommand subkey shown in the following figure:
   
   <<=== NOTE: Modify this key.
   
2. In the right pane, double-click the (Default) value.
3. Delete the current value data, then type: "%1" %* (That is, type the characters: quote-percent-one-quote-space-percent-asterisk.).
   
   NOTES:
   • Under Windows 95/98/Me/NT, the Registry Editor automatically encloses the value within quotation marks. When you click OK, the (Default) value should look exactly like this:
     
     ""%1" %*"  
     
   • Under Windows 2000/XP, the additional quotation marks will not appear. When you click OK, the (Default) value should look exactly like this:
     
     "%1" %*
     
   • Make sure that you completely delete all the value data in the command key before you type the correct data. If you leave a space at the beginning of the entry, any attempt to run any program files will result in the error message, "Windows cannot find .exe." If this occurs, restart the entire process from the beginning of this document and make sure that you completely remove the current value data.
     
4. Exit the Registry Editor.

Updating 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 the 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) line at the top of this writeup.
• 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) line at the top of this writeup.
  
  The 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.

Scanning for and deleting 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 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 Infostealer.Rimd, click Delete.