What is the Netsky.N worm?

Netsky.N is a mass-mailing worm that uses its own SMTP engine to send itself to the email addresses it finds when scanning hard drives and mapped drives.

Also known as: WORM_Netsky.N, W32/Netsky.N@MM, W32/Netsky.N.worm, Win32.Netsky.N

How Does the Netsky.N Worm Infect My Computer?

When Netsky.N runs, it does the following:

1. Creates a mutex named "NetDy_Mutex_Psycho". This mutex allows only one instance of the worm to execute.
   
   
2. Copies itself as %Windir%\VisualGuard.exe.
   
   
3. Creates the following files:
   
   • %Windir%\base64.tmp (46,308 bytes): MIME-encoded version of the executable
   • %Windir%\zip1.tmp (46,478 bytes): MIME-encoded version of worm in zip archive
   • %Windir%\zip2.tmp (46,490 bytes): MIME-encoded version of worm in zip archive
   • %Windir%\zip3.tmp (46,464 bytes): MIME-encoded version of worm in zip archive
   • %Windir%\zip4.tmp (46,646 bytes): MIME-encoded version of worm in zip archive
   • %Windir%\zip5.tmp (46,658 bytes): MIME-encoded version of worm in zip archive
   • %Windir%\zip6.tmp (46,670 bytes): MIME-encoded version of worm in zip archive
   • %Windir%\zipped.tmp (34,054 bytes): Worm in zip archive
     
     
4. Adds the value:
   
   "NetDy"="%Windir%\VisualGuard.exe"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   so that the worm runs when you start Windows.
   
   
5. Deletes the values:
   
   Explorer
   system.
   msgsvr32
   au.exe
   service
   DELETE ME
   d3dupdate.exe
   OLE
   Sentry
   gouday.exe
   rate.exe
   Taskmon
   Windows Services Host
   sysmon.exe
   srate.exe
   ssate.exe
   
   from the registry key:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   
6. Deletes the value:
   
   InProcServer32
   
   from the registry key:
   
   HKEY_CLASSES_ROOT\CLSID\CLSID\{E6FB5E20-DE35-11CF-9C87-00AA005127ED}
   
   
7. Deletes the following subkeys:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
   Explorer\PINF
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WksPatch
   
   
8. Retrieves email addresses from the files with these extensions:
   
   • .adb
   • .asp
   • .cgi
   • .dbx
   • .dhtm
   • .doc
   • .eml
   • .htm
   • .html
   • .jsp
   • .msg
   • .oft
   • .php
   • .pl
   • .rtf
   • .sht
   • .shtm
   • .tbb
   • .txt
   • .uin
   • .vbs
   • .wab
   • .wsh
   • .xml
     
     
9. Uses its own SMTP engine to send itself to the email addresses it finds. The worm uses the local DNS server (retrieved using an API call), if available, to perform an MX lookup for the recipient address.
   

How to Remove the Netsky.N Worm?

Kaspersky Internet Security Can Prevent You From Virus and Intrusion. If Kaspersky detects Netsky.N during the scan, it will AUTOMATICALLY offer you the option of deleting it. Do this by following the program's instructions.

Follow these steps in removing the Netsky.N worm.

1. Disabling System Restore (Windows Me/XP)

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/XP System Restore".

2. Updating the Virus Definitions

If you do not know which anti-virus software can provide strong protection for you, Kaspersky Internet Security is recommended.

3. Identifying the Virus Program

1. Scan your system with your Kaspersky antivirus products.
2. NOTE all files detected as Netsky.N.

4. Terminating the Running Program

1. Open Windows Task Manager.
   On Windows 95/98/ME systems, press
   CTRL+ALT+DELETE
   On Windows NT/2000/XP systems, press
   CTRL+SHIFT+ESC, then click the Processes tab.
2. In the list of running programs*, locate the malware file or files detected earlier.
3. Select one of the detected files, then press either the End Task or the End Process button, depending on the version of Windows on your system.
4. Do the same for all detected malware files in the list of running processes.
5. To check if the malware process has been terminated, close Task Manager, and then open it again.
6. Close Task Manager.

5. Removing Autostart Entries from the Registry

1. Open Registry Editor. To do this, click Start>Run, type Regedit, then press Enter.
2. In the left panel, double-click the following:
   HKEY_LOCAL_MACHINE>Software>Microsoft>
   Windows>CurrentVersion>Run
3. In the right panel, locate and delete the entry or entries:
   "NetDy" = "%Windows%\VisualGuard.exe"
   Note: %Windows% is the default Windows folder, usually C:\Windows or C:\WINNT.
4. Close Registry Editor.

6. Deleting Malware Files

• Right-click Start then click Search. or Find. depending on your version of Windows.
• In the Named input box, type:
  BASE64.TMP
  ZIP1.TMP
  ZIP2.TMP
  ZIP3.TMP
  ZIP4.TMP
  ZIP5.TMP
  ZIP6.TMP
• In the Look In drop-down list, select the drive which contains Windows, then press Enter.
• Once located, select the file then hit Delete.

1. Start your Kaspersky Internet Security and make sure that it is configured to scan all the files.
2. Run a full system scan.
3. If any files are detected as infected with Netsky.N, click Delete.

How to Disinfect My Computer from Worms?

In order to keep your computer protected, bear the following tips in mind:

1. If you have filtering tools installed, configure them to reject messages with the characteristics described above. If, in spite of doing this, you receive the message that contains the virus: do not open it, do not run the attached file and delete it, making sure that you also delete it from the Deleted Items folder.
2. Install a good antivirus in your computer. Select Kaspersky Internet Security to get the Kaspersky antivirus solution that best suits your needs.
3. Keep your antivirus updated. If automatic updates are available, configure your antivirus to use them.
4. Keep your permanent antivirus protection enabled at all times.

Detect and Removal Instruction for Other Variants: