Worm.Win32.YAHLOVER.A

To delete the registry value this malware created:

1. Open Registry Editor. To do this:
   » For Windows 7 and Windows Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
   » For Windows 8, Windows 8.1, 10, and Windows Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box provided, and then press Enter.
2. In the left panel of the Registry Editor window, double-click the following:
   HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Run
3. In the right panel, locate and delete the entry:
   smss = %System Root%\WINDOW\System32\smss.exe
4. In the left panel of the Registry Editor window, double-click the following:
   HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>services>wuauserv
5. In the right panel, locate and delete the entry:
   Start = 4
6. In the left panel of the Registry Editor window, double-click the following:
   HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>services>Sr
7. In the right panel, locate and delete the entry:
   Start = 4
8. Again In the right panel, locate and delete the entry:
   ImagePath = \%SystemRoot%\system32\DRIVERS\sr.sys
9. In the left panel of the Registry Editor window, double-click the following:
   HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>services>Sr>Parameters
10. In the right panel, locate and delete the entry:
    FirstRun = 1
11. Again In the right panel, locate and delete the entry:
    Start = 4
12. Again In the right panel, locate and delete the entry:
    ImagePath = \%SystemRoot%\system32\DRIVERS\sr.sys
13. Again In the right panel, locate and delete the entry:
    FirstRun = 1
14. In the left panel of the Registry Editor window, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>services>usnjsvc
15. In the right panel, locate and delete the entry:
    Start = 3
16. In the left panel of the Registry Editor window, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>services>srservice
17. In the right panel, locate and delete the entry:
    Start = 4
18. In the left panel of the Registry Editor window, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>services>ekrn
19. In the right panel, locate and delete the entry:
    Start = 4
20. In the left panel of the Registry Editor window, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>services>EhttpSrv
21. In the right panel, locate and delete the entry:
    Start = 4
22. Close Registry Editor.

To restore the registry value this malware/grayware modified:

1. Open Registry Editor.
   » For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
   » For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box provided, and then press Enter.
2. In the left panel, double-click the following:
   HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>CurrentVersion>Policies>System
3. In the right panel, locate the registry value:
   EnableLUA = 0
4. Right-click on the value name and choose Modify. Change the value data of this entry to:
   EnableLUA = 1
5. In the left panel, double-click the following:
   HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>SystemRestore
6. In the right panel, locate the registry value:
   DisableSR = 1
7. Right-click on the value name and choose Modify. Change the value data of this entry to:
   DisableSR = 0
8. In the left panel, double-click the following:
   HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Explorer>Advanced
9. In the right panel, locate the registry value:
   Hidden = 2
10. Right-click on the value name and choose Modify. Change the value data of this entry to:
    Hidden = 1
11. Close Registry Editor.

To manually delete a malware/grayware file from an affected system:

•For Windows 7, Windows Server 2008 (R2), Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2):

1. Open a Windows Explorer window.
   • For Windows 7 and Server 2008 (R2) users, click Start>Computer.
   • For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower-left corner of the screen,then click File Explorer.
2. In the Search Computer/This PC input box, type:
   
   • %System Root%\WINDOW\System32\smss.exe
   • {Every folder}\{Folder name}.exe
   • {removable drives}\smss.exe
   • %System%\drivers\etc\hosts
   • %System Root%\WINDOW\System32\Declare.ini
   • {removable drives}\autorun.inf
3. Once located, select the file then press SHIFT+DELETE to delete it.
   *Note: Read the following Microsoft page if these steps do not work on Windows 7 and Windows Server 2008 (R2).