IRC.Vale.Worm

SUMMARY

IRC.Vale.Worm is both an IRC worm and a mass mailer. It sends itself to other users using the IRC channel and email. IRC.Vale.Worm is a batch file that includes VBScript code.

When IRC.Vale.Worm is executed, it creates a VBScript file that displays messages. Refer to "Technical Details" for illustrations of these messages.

Protection

• Virus Definitions (LiveUpdate™ Weekly) March 19, 2003
• Virus Definitions (Intelligent Updater) March 15, 2003

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

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

When IRC.Vale.Worm is executed, it performs the following actions:

1. Checks to see whether a batch file named Config.bat exists in the root of the C: drive. If the file is already on the system, the worm knows that the system was previously infected. IRC.Vale.Worm executes Msg.vbs, Vale.vbs, and Mirko.vbs in the %Windir%Vale directory to show some messages and to spread itself through emails.
   
   NOTE: %Windir% is a variable. The Trojan locates the Windows installation folder (by default, this is C:Windows or C:Winnt) and copies the file to that location.
   
   If Config.bat does not exist under drive C, the worm will infect the machine by completing the following tasks.
   
2. Creates a sub-directory named Vale under %Windir% and copies itself to this directory as Config.bat.
   
3. Changes the name of the file, Format.com, to Scanreg.com if Format.com exists in the directory, %Windir%Command.
   
4. Creates a VBScript file named Msg.vbs in the %Windir%Vale directory if no such file exists.
   
   This VBScript file displays the following message boxes:
   
   
   
   
   
   
   
   
5. Creates a registry key file, Mirko.reg, in the %Windir%Vale directory if no such file exists. The Registry Editor loads this registry key file to add the value:
   
   ConfigWin C:\config.bat
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   so that the worm executes when you start or restart Windows.
   
6. Adds the following line to C:Autoexec.bat:
   
   @if not exist C:config.bat scanreg C: /q /u /autotest
   
   so that the C drive will be formatted if the file, C:Config.bat, does not exist.
   
7. Creates a VBScript file named Vale.vbs in the %Windir%Vale directory if no such file exists. This VBScript file sends email to everyone in the Microsoft Outlook Address Book. The email message sent to the Microsoft Outlook email addresses looks like:
   
   Subject: For YOU, Per TE
   Body: Io provo un grande amore per te.. Farei di tutto per TE
   Attachment: c:config.bat
   
8. Creates a VBScript file named Mirko.vbs in the %Windir%Vale directory if no such file exists. This VBScript file sends email to everyone in the Microsoft Outlook Address Book. The email message sent to the Microsoft Outlook email addresses looks like:
   
   Subject: MAIL FOR YOU !!
   Body: Sei il mio più grande desiderio... TI AMO !!
   Attachment: c:config.bat
   
9. Modifies the file, Script.ini, in one of the following possible locations:
   
   • C:Mirc
   • C:Mirc32
   • C:Progra~1Mirc
   • C:Progra~1Mirc32
     
     This Script.ini is modified to send C:Config.bat to the host system.
     

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

1. Update the virus definitions.
2. Run a full system scan and delete all the files detected as IRC.Vale.Worm.
3. Reverse the changes that the Trojan made to the registry.
   

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

1. 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 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 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. 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 IRC.Vale.Worm, click Delete.

3. Reversing the changes made to the registry

CAUTION: 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. Read the document, "How to make a backup of the Windows registry," for instructions.

1. Click Start, and then click Run. (The Run dialog box appears.)
2. Type regedit, and then click OK. (The Registry Editor opens.)
3. Navigate to the key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete the value: ConfigWin
5. Exit the Registry Editor.