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  3. Trojan.Zeroaccess!gen9

Trojan.Zeroaccess!gen9 - Removal

Risk Level 1: Very Low

Discovered:
February 17, 2012
Updated:
November 9, 2012 3:38:19 PM
Type:
Trojan
Systems Affected:
Windows 2000, Windows NT, Windows Server 2003, Windows Server 2008, Windows Vista, Windows XP
You may have arrived at this page either because you have been alerted by your Symantec product about this risk, or you are concerned that your computer has been affected by this risk.

Before proceeding further we recommend that you run a full system scan. If that does not resolve the problem you can try one of the options available below.



FOR NORTON USERS
If you are a Norton product user, we recommend you try the following resources to remove this risk.

Removal Tool

If you have an infected Windows system file, you may need to replace them using from the Windows installation CD.


How to reduce the risk of infection
The following resources provide further information and best practices to help reduce the risk of infection.


FOR BUSINESS USERS
If you are a Symantec business product user, we recommend you try the following resources to remove this risk.

Identifying and submitting suspect files
Submitting suspicious files to Symantec allows us to ensure that our protection capabilities keep up with the ever-changing threat landscape. Submitted files are analyzed by Symantec Security Response and, where necessary, updated definitions are immediately distributed through LiveUpdate™ to all Symantec end points. This ensures that other computers nearby are protected from attack. The following resources may help in identifying suspicious files for submission to Symantec.


Removal Tool

If you have an infected Windows system file, you may need to replace them using from the Windows installation CD.


How to reduce the risk of infection
The following resource provides further information and best practices to help reduce the risk of infection.
Protecting your business network



MANUAL REMOVAL
The following instructions pertain to all current Symantec antivirus products.

1. Performing a full system scan
How to run a full system scan using your Symantec product


2. Restoring settings in the registry
Many risks make modifications to the registry, which could impact the functionality or performance of the compromised computer. While many of these modifications can be restored through various Windows components, it may be necessary to edit the registry. See in the Technical Details of this writeup for information about which registry keys were created or modified. Delete registry subkeys and entries created by the risk and return all modified registry entries to their previous values.


3. Restore detected files using the Windows Recovery Console in Windows XP
Since this threat modifies or replaces system files, it is necessary to recover the affected files using the Windows Recovery Console. To do this it is necessary to restart the computer and run the Windows Recovery Console. For full details on how to do this please read the Microsoft Knowledge Base article, How to install and use the Recovery Console in Windows XP.
  1. Insert the Windows XP CD-ROM into the CD-ROM drive.
  2. Restart the computer from the CD-ROM drive.
  3. Press R to start the Recovery Console when the "Welcome to Setup" screen appears.
  4. Select the installation that you want to access from the Recovery Console.
  5. Enter the administrator password and press Enter.
  6. To restore files detected as Trojan.Zeroaccess!inf, Trojan.Zeroaccess!inf2, or Trojan.Zeroaccess!inf3, type the following commands and press Enter after each command:

    • cd %System%\drivers [SYS FILES]
    • expand [CD/DVD DRIVE]:\i386\[DETECTED FILE NAME].[dl or sy]_

      For example:

      cd c:\windows\system32\drivers
      expand d:\i386\atapi.sy_

  7. Repeat the above step for each SYS or DLL file affected.
  8. Type exit.
  9. Press Enter. The computer will now restart automatically.

4. Restore detected files using System Recovery Options in Windows Vista/7
Since this threat modifies or replaces system files, it is necessary to recover the affected files using the System Recovery Options. To do this it is necessary to restart the computer and run the System Recovery Options. For full details on how to do this please read What are the system recovery options in Windows Vista or What are the system recovery options in Windows 7.
  1. Restart the computer.
  2. As the computer restarts, press F8 repeatedly until the Advanced Boot Options screen appears.
  3. Select Repair Your Computer and press Enter.
  4. Select the keyboard input method and click Next.
  5. Select an administrator account, enter your password, and click OK.
  6. On the System Recovery Options menu, click Command Prompt.
  7. To restore files detected as Trojan.Zeroaccess!inf, Trojan.Zeroaccess!inf2, or Trojan.Zeroaccess!inf3, type the following commands and press Enter after each command:

    For users with a Windows Vista/7 disk or recovery disk
    Insert the disk into the CD/DVD drive

    • cd %System%\drivers [SYS FILES]
    • expand [CD/DVD DRIVE]:\Windows\[DETECTED FILE NAME].[dl or sy]_

      For example:
      cd c:\windows\system32\drivers
      expand d:\Windows\serial.sy_

    For users with a recovery partition
    Refer to your computer manufacturer's documentation for the location of the backup system files

    • cd %System%\drivers [SYS FILES]
    • expand [DRIVE LETTER]:\[SYSTEM FILES FOLDER]\[DETECTED FILE NAME].[dl or sy]_

      For example:
      cd c:\windows\system32\drivers
      expand f:\Windows\serial.sy_

  8. Repeat the above step for each SYS or DLL file affected.
  9. Close the Command Prompt window.
  10. Click Restart on the System Recovery Options menu. The computer will now restart.

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