W32.Netsky@mm

SUMMARY

W32.Netsky@mm is a mass-mailing worm that uses its own SMTP engine to send itself to the email addresses it finds when scanning the hard drives and mapped drives. This worm also searches drives C through Z for the folder names containing "Share" or "Sharing," and then copies itself to those folders.

The "From" and attachment names of the email vary.

Protection

• Virus Definitions (LiveUpdate™ Weekly) February 16, 2004
• Virus Definitions (Intelligent Updater) February 16, 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: Uses its own SMTP engine to send itself to the email addresses it retrieves from the files whose extension is one of the following: .adb, .asp, .dbx, .doc, .eml, .htm, .html, .msg, .oft, .php, .pl, .rtf, .sht, .tbb, .txt, .uin, .vbs, and .wab.

Distribution

• Distribution Level: Medium
• Subject of Email: Auction successful!
• Name of Attachment: prod_info_55761.rtf.exe.zip prod_info_65642.rtf.scr.zip prod_info_33543.rtf.scr.zip prod_info_56474.txt.exe.zip prod_info_33325.txt.exe.zip prod_info_77256.txt.scr.zip prod_info_34157.htm.exe.zip prod_info_87968.htm.scr.zip prod_info_43859.htm.scr.zip prod_info_56780.doc.exe.zip prod_info_43631.doc.exe.zip prod_info_47532.doc.scr.zip prod_info_54433.doc.exe.zip prod_info_42314.pif prod_info_54235.scr prod_info_49146.exe prod_info_33967.cmd prod_info_42818.pif prod_info_54739.scr prod_info_04650.bat prod_info_49541.exe prod_info_33462.cmd prod_info_42313.pif prod_info_54234.scr prod_info_04155.bat
• Size of Attachment: 21,504
• Target of Infection: Searches all the folders whose names contain "Share" or "Sharing" on drives C to Z, and then copies itself to the folder, if the drive is not the CD-ROM drive.

TECHNICAL DETAILS

When W32.Netsky@mm runs, it does the following:

1. Creates a mutex named "AdmMoodownJKIS003." This mutex allows only one instance of the worm to execute in memory.
   
   
2. Copies itself as %Windir%Services.exe.
   
   

   ---

   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.

   ---

   
   
3. Adds the value:
   
   "Service" = "%Windir%services.exe -serv"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   so that it runs when you restart Windows.
   
   
4. Deletes the values:
   
   • "Taskmon"
   • "Explorer"
     
     from the registry keys:
     
   • HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   • HKEY_CURRENT_USERSOFTWAREMicrosoftWindowsCurrentVersionRun
     
     
5. Deletes the values:
   
   • "KasperskyAV"
   • "System."
     
     from the registry key:
     
     HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
     
     
6. Deletes the registry key:
   
   HKEY_CLASSES_ROOTCLSID{E6FB5E20-DE35-11CF-9C87-00AA005127ED}InProcServer32
   
   
7. May copy itself to the %Windir% folder as one of the following:
   • prod_info_55761.rtf.exe.zip
   • prod_info_65642.rtf.scr.zip
   • prod_info_33543.rtf.scr.zip
   • prod_info_56474.txt.exe.zip
   • prod_info_33325.txt.exe.zip
   • prod_info_77256.txt.scr.zip
   • prod_info_34157.htm.exe.zip
   • prod_info_87968.htm.scr.zip
   • prod_info_43859.htm.scr.zip
   • prod_info_56780.doc.exe.zip
   • prod_info_43631.doc.exe.zip
   • prod_info_47532.doc.scr.zip
   • prod_info_54433.doc.exe.zip
     
     
8. Retrieves email addresses from the files with the following file extensions:
   
   • .msg
   • .oft
   • .sht
   • .dbx
   • .tbb
   • .adb
   • .doc
   • .wab
   • .asp
   • .uin
   • .rtf
   • .vbs
   • .html
   • .htm
   • .pl
   • .php
   • .txt
   • .eml
     
     

     ---

     Note: Due to a bug in the code, the worm will search a file for email addresses if the extension is a sub-string of one of the aforementioned extensions.
     
     For example, the worm will scan the files with the .txt, .tx, and .t extensions.

     ---

     
     
9. Searches drives C through Z for the folder names containing the words "Share" or "Sharing." If the drive is not a CD-ROM, the worm copies itself as the following:
   • doom2.doc.pif
   • sex sex sex sex.doc.exe
   • rfc compilation.doc.exe
   • dictionary.doc.exe
   • win longhorn.doc.exe
   • e.book.doc.exe
   • programming basics.doc.exe
   • how to hack.doc.exe
   • max payne 2.crack.exe
   • e-book.archive.doc.exe
   • virii.scr
   • nero.7.exe
   • eminem - lick my pussy.mp3.pif
   • cool screensaver.scr
   • serial.txt.exe
   • office_crack.exe
   • hardcore porn.jpg.exe
   • angels.pif
   • porno.scr
   • matrix.scr
   • photoshop 9 crack.exe
   • strippoker.exe
   • dolly_buster.jpg.pif
   • winxp_crack.exe
     
     
10. Uses its own SMTP engine to send itself to the email addresses it found.
    
    The email has the following characteristics:
    
    From: (Spoofed as one of the following):
    
    • Ebay Auctions <responder@ebay.com>    
    • Yahoo Auctions <auctions@yahoo.com>
    • Amazon automail <responder@amazon.com>
    • MSN Auctions <auctions@msn.com>
    • QXL Auctions <responder@qxl.com>
    • EBay Auctions <responder@ebay.com>
      

Subject: Auction successful!

Message:
#----------------- message was sent by automail agent ------------------#


Congratulations!


You were successful in the auction.

Auction ID       :<4 random digits>-<4 random digits>-<4 random digits>-A
Product ID       :<4 random digits>-<4 random digits>-<4 random digits>-P

A detailed description about the product and the bill
are attached to this mail.
Please contact the seller immediately.

Thank you!

Attachment: (One of the following):

• prod_info_55761.rtf.exe.zip
• prod_info_65642.rtf.scr.zip
• prod_info_33543.rtf.scr.zip
• prod_info_56474.txt.exe.zip
• prod_info_33325.txt.exe.zip
• prod_info_77256.txt.scr.zip
• prod_info_34157.htm.exe.zip
• prod_info_87968.htm.scr.zip
• prod_info_43859.htm.scr.zip
• prod_info_56780.doc.exe.zip
• prod_info_43631.doc.exe.zip
• prod_info_47532.doc.scr.zip
• prod_info_54433.doc.exe.zip
• prod_info_42314.pif
• prod_info_54235.scr
• prod_info_49146.exe
• prod_info_33967.cmd
• prod_info_42818.pif
• prod_info_54739.scr
• prod_info_04650.bat
• prod_info_49541.exe
• prod_info_33462.cmd
• prod_info_42313.pif
• prod_info_54234.scr
• prod_info_04155.bat

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.Netsky@mm.
4. 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"

---

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. 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. 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.Netsky@mm, click Delete.

4. Deleting the value from the registry

---

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.

---

1. Click Start, and then click Run. (The Run dialog box appears.)
   
2. Type regedit
   
   Then click OK. (The Registry Editor opens.)
   
   
3. Navigate to the key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
4. In the right pane, delete the value:
   
   "Service" = "%Windir%services.exe -serv"
   
   
5. Exit the Registry Editor.