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Microsoft Security Intelligence
Published May 24, 2007 | Updated Sep 15, 2017

TrojanDownloader:Win32/VB.BZ

Detected by Microsoft Defender Antivirus

Aliases: Win32/Cadux.AN (CA) Trojan-Downloader.Win32.VB.afr (Kaspersky) TFactory (McAfee) W32/DLoader.AEFX (Norman) Troj/SpyDldr-K (Sophos) Trojan.FakeAlert (Sunbelt Software) Adware.Topantispyware (Symantec) TROJ_DLOADER.CFS (Trend Micro)

Summary

TrojanDownloader:Win32/VB.BZ displays erroneous warning messages in an attempt to mislead the user into believing they are infected with malicious software. The program then prompts the user to download additional software in order to resolve the erroneously detected issues.
To recover manually from infection by TrojanDownloader:Win32/VB.BZ, perform the following steps:
  • Disconnect from the Internet.
  • Restart the computer in safe mode.
  • End the Trojan process.
  • Delete the Trojan files from your computer.
  • Delete the Trojan registry entries.
  • Restart the computer. 
  • Take steps to prevent re-infection.

Disconnect from the Internet

To help ensure that your computer is not actively infecting other computers, disconnect it from the Internet before proceeding. Print this Web page or save a copy on your computer; then unplug your network cable and disable your wireless connection. You can reconnect to the Internet after completing these steps.

Restart the computer in safe mode

To start your computer in safe mode
  1. Remove all floppy disks and CDs from your computer, and then restart your computer.
  2. When prompted, press F8. If Windows starts without displaying the Please select the operating system to start menu, restart your computer. Press F8 after the firmware POST process completes, but before Windows displays graphical output.
  3. From the Windows Advanced Options Menu, select a safe mode option.

End the Trojan process

To end the Trojan process
  1. Press CTRL+ALT+DEL once and click Task Manager
  2. Click Processes and click Image Name to sort the running processes by name.
  3. Select the Trojan process 'smvmnvcc.exe' and click End Process.

Delete the Trojan files from your computer

To delete the Trojan files from your computer
  1. Click Start, and click Run.
  2. In the Open field, type the location of the Windows system folder, typically C:\Windows\System32
  3. Click OK.
  4. Click Name to sort files by name.
  5. Delete the following files from the <system folder>
    users32.exe
    adobepnl.dll
    smvmnvcc.exe
    main.exe
  6. On the Desktop, right-click the Recycle Bin and click Empty Recycle Bin.
  7. Click Yes to confirm the deletion.
If deleting the file fails, use the following steps to verify that the file is not running:
  1. Press CTRL+ALT+DEL once and click Task Manager.
  2. Click Processes and click Image Name to sort the running processes by name.
  3. Confirm that the file 'smvmnvcc.exe' is not in the list:

Delete the Trojan registry entries

To delete the Trojan registry entries
  1. On the Start menu, click Run.
  2. Type regedit and click OK.
  3. In the left pane, navigate to the key:
    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  4. In the right pane, right-click the following value, if it exists: Adware.Svr32
  5. Click Delete and click Yes to delete the value.
  6. In the left pane, navigate to the key: HKEY_LOCAL_MACHINE\Software\
  7. In the right pane, right-click each of the following values, if they exist: "Alexa Internet" and "Alexa Toolbar"
  8. Click Delete and click Yes to delete the values.
  9. In the left pane, navigate to the key: HKEY_LOCAL_MACHINE\Software\Classes\
  10. In the right pane, right-click each of the following values, if they exist, and click Delete and click Yes to delete the values: 
    AlxTB.BHO
    Bridge.brdg
    clsid\{60e2e76b-60e2e76b-60e2e76b-60e2e76b-60e2e76b}
    clsid\{60e2e76b-60e2e76b-60e2e76b-60e2e76b-60e2e76b}
    clsid\{9896231A-C487-43A5-8369-6EC9B0A96CC0}
    clsid\{B53455DB-5527-4041-AC41-F86E6947AA47}
    clsid\{E52DEDBB-D168-4BDB-B229-C48160800E81}
    clsid\{F1FABE79-25FC-46de-8C5A-2C6DB9D64333}
    clsid\{F1FABE79-25FC-46de-8C5A-2C6DB9D64333}
    DailyToolbar.SysMgr
    jao.jao
    office_pnl.office_panel
    PopMenu.Menu
    Popup.HTMLEvent.
    Popup.PopupKiller
    Popup.PopupKiller
    url_relpacer.URLResolver
    WStart.WHttpHelper
    WStart.WHttpHelper.1
  11. In the left pane, navigate to the key: HKEY_LOCAL_MACHINE\Software\
  12. In the right pane, right-click the following values, if they exists: "DailyToolbar" and "WSoft"
  13. Click Delete and click Yes to delete the value.
  14. In the left pane, navigate to the key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
  15. In the right pane, right-click each of the following values, if they exist, and click Delete and click Yes to delete the values: 
    {3ceff6cd-6f08-4e4d-bccd-ff7415288c3b}
    {7b55bb05-0b4d-44fd-81a6-b136188f5deb}
    {B53455DB-5527-4041-AC41-F86E6947AA47}
    {e52dedbb-d168-4bdb-b229-c48160800e81}
  16. In the left pane, navigate to the key: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall\
  17. In the right pane, right-click each of the following values, if they exist, and click Delete and click Yes to delete the values:
    Alexa Toolbar
    bridgeClick
  18. Close the Registry Editor.

Restart the computer

To restart your computer
  1. On the Start menu, click Shut Down.
  2. Select Restart from the drop-down list and click OK.

Take steps to prevent re-infection

You should not reconnect your computer to the Internet until the computer is protected from re-infection. See the "Preventing Infection" section for more information.
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