W32.Mimail.T@mm

SUMMARY

W32.Mimail.T@mm is a mass mailing worm. It attempts to mail itself to the email addresses found on the system. The message body and subject lines can vary.

Protection

• Virus Definitions (LiveUpdate™ Weekly) February 11, 2004
• Virus Definitions (Intelligent Updater) February 6, 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: Sends to email addresses harvested from the infected system.

Distribution

• Distribution Level: High
• Subject of Email: varies
• Name of Attachment: varies with .exe, .pif, or .scr file extension
• Size of Attachment: 14,880 bytes

TECHNICAL DETAILS

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

1. Copies itself to:
   • %Windir%Kaspersky.exe
   • %Windir%Ee98af.tmp
     

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     Note: %Windir% is a variable. The worm locates the Windows installation folder (by default, this is C:Windows or C:Winnt) and copies itself to that location.

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2. Registers itself as a service process.
   
3. Adds the value:
   
   "KasperskyAv" = " %Windir%kaspersky.exe"
   
   to registry key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   so that the worm runs when you start Windows.
   
4. Attempts to resolve the IP address for www.google.com to determine whether there is Internet connectivity.
   
5. Collects email addresses from all the files on the computer, except those that have these extensions:
   • jpg
   • gif
   • exe
   • dll
   • avi
   • mpg
   • mp3
   • vxd
   • ocx
   • psd
   • tif
   • zip
   • rar
   • pdf
   • cab
   • wav
   • com
     
6. Sends email messages using its own SMTP engine. For each email address the worm gathers, it acquires a mail server associated with that email address from the system DNS or DNS server at IP 212.5.86.163. Then, its SMTP engine directly contacts the destination mail server.
   
   The subject lines, attachment names, and message bodies vary:
   
   The first part of the attachment name consists of one of the following words:
   
   my
   priv
   private
   prv
   the
   best
   super
   great
   cool
   wild
   sex
   fXck
   
   followed by an one or two underscores or a dash, and then one of the following words:
   
   pic
   img
   phot
   photos
   pctrs
   images
   imgs
   scene
   plp
   act
   action
   
   and one of the following extensions:
   
   .pif
   .scr
   .exe
   .jpg.scr
   .jpg.pif
   .jpg.exe
   .gif.exe
   .gif.pif
   .gif.scr
   
7. Performs a Denial of Service (DoS) that has the following characteristics:
   1. Randomly selects a site from the names below:
      • darkprofits.net
      • darkprofits.cc
      • darkprofits.com
      • spew.org
        
   2. Randomly chooses to perform a TCP connection on port 80 or to perform an ICMP attack. The packets that are sent to the victim carry a 2 KB payload filled with random data.
   3. Uses a random ICMP type when performing the ICMP attack.
   4. Sends data using either the GET request or some random data when performing the HTTP connection.
      

The worm contains text threatening to perform a Denial of Service (DoS) on a particular ISP and on any ISP that attempts to prevent stolen information from reaching the author.

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. Restart the computer in Safe mode or VGA mode.
4. Run a full system scan and delete all the files detected as W32.Mimail.T@mm.
5. Delete the value that was added to the registry.
   

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

1. Disabling 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"

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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.

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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. 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: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

3. Restarting the computer in Safe mode or VGA mode

Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode or VGA mode.

• For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."
• For Windows NT 4 users, restart the computer in VGA mode.

4. 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 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.Mimail.T@mm, click Delete.

5. Deleting the value from the registry

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WARNING: 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.

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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:
   
   "KasperskyAv" = " %Windir%kaspersky.exe"
   
5. Exit the Registry Editor.