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What do you know about the Mebroot trojan, also known as Sinowal? Answered

I did a clean Windows install on a brand new hard disk for a friend. But when transferring her files over, we discovered she had Mebroot on her old hard disk and thumb drives. AVG antivirus did not detest it at all! Symantec does detect it, but cannot remove it. After doing some searching, this is what I've found. It's a boot sector trojan that apparently takes an expert to remove?? 80% of antivirus software does not even detect it? It allows a backdoor into your computer which can steal any information, including your online banking information, and no antivirus program can remove it or protect against it?? Even a reformatting of the hard disk (or thumb drive) does not remove it??!



10 years ago

try a2 squareed free from emsisoft


Answer 10 years ago

Have you actually used this, youself? There's a thousand free tools avail for download with any given search, but it's hard to tell which ones are just malware, themselves.


Answer 10 years ago

Thanks, but it's not doing anything that I'm aware of. It's just there. I was able to find the same info you're posting, but I appreciate it, anyway. I have seen posts that seem to make it clear that symantec tool does not actually remove it, either. I haven't contacted symantec support, yet, but I also just have the free trial version. My friend has decided that she's just gonna live with it for now.


Answer 10 years ago

Oh, it might block symantec also:

Discovered: January 7, 2008
Updated: January 8, 2008 4:45:30 PM
Type: Trojan
Infection Length: Varies
Systems Affected: Windows XP, Windows Vista, Windows Server 2003, Windows 2000

Removal Tool
Symantec have developed a tool to remove this threat. Please contact Symantec Technical Support for further information.

Manual Removal:
The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Restart the computer using the Windows Recovery Console.
2. Disable System Restore (Windows Me/XP).
3. Update the virus definitions.
4. Run a full system scan.

For specific details on each of these steps, read the following instructions.

1. To restart the computer using the Windows Recovery Console
To remove this threat 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. Type the following command and press Enter:
7. Following the onscreen instructions to restore the Master Boot Record.
8. Type exit
9. Press Enter. The computer will now restart automatically.

2. To disable 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, reenable 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).

3. To update 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.
If you use Norton AntiVirus 2006, Symantec AntiVirus Corporate Edition 10.0, or newer products, LiveUpdate definitions are updated daily. These products include newer technology.

If you use Norton AntiVirus 2005, Symantec AntiVirus Corporate Edition 9.0, or earlier products, LiveUpdate definitions are updated weekly. The exception is major outbreaks, when definitions are updated more often.
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. You should download the definitions from the Symantec Security Response Web site and manually install them.

The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.

4. To run a full system scan

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, follow the instructions displayed by your antivirus program.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode. Once you have restarted in Safe mode, run the scan again.
After the files are deleted, restart the computer in Normal mode.

10 years ago

Have you tried comboFix.exe? It is pretty good at removing other stubborn things.


Answer 10 years ago

No, but from what I have seen, it requires some knowledge to use, which I don't have.


10 years ago

have you tried deleting the partition and then recreating it?


Answer 10 years ago

Yeah. This doesn't do anything, because it resides on the boot sector.