Monday, March 10, 2008

Remove __.vbs, __.bat, __.reg and autorun.inf


ComboFix is a program, created by sUBs, that scans your computer for known malware, and when found, attempts to clean these infections automatically. In addition to being able to remove a large amount of the most common and current malware, ComboFix also displays a log when it is finished that contains a great deal of information that an experienced helper can use to diagnose, retrieve samples of, and remove infections that are not automatically removed.

Due to the power of this tool it is strongly advised that you do not attempt to act upon any of the information displayed by ComboFix without supervision from someone who has been properly trained. If you do so, it may lead to problems with the normal functionality of your computer. Instead you should use this guide to download and run ComboFix and then post the resulting log in a forum that contains helpers who understand how to diagnose them. These helpers will then help you clean your computer of infections so that it is running properly again.

Please note that this guide is the only authorized guide for the use of ComboFix and cannot be copied without permissions from and sUBs. It is also understood that the use of ComboFix is done at your own risk.

Using ComboFix

The first thing you should do is print out this guide as we will close all the open windows and programs, including your web browser, before starting the ComboFix program.

Next you should download ComboFix from one of the following URLs:

To download ComboFix, simply left-click on one of the links above and if you are using Internet Explorer, you will see a prompt similar to the figure below.

Download ComboFix Screenshot
Download ComboFix Prompt

Click on the Save button and then when it asks you where to save it, make sure you save it directly to your Windows Desktop. An image showing this is below.

Downloading ComboFix to the Desktop
Downloading ComboFix to the Desktop

When you have the Save as screen configured to save ComboFix.exe to the Desktop, click on the Save button. ComboFix will now start downloading to your computer. If you are on a dialup, this may take a few minutes. When ComboFix has finished downloading you will now see an icon on your desktop similar to the one below.

ComboFix Icon
ComboFix Icon

For now, do not start ComboFix as there are a few more steps that need to be done first.

We now suggest that you install the Windows Recovery Console. The Windows recovery console will allow you to boot up into a special recovery mode that allows us to help you in the case that your computer has a problem after an attempted removal of malware. If you use Windows XP and have a Windows CD, then you can follow the instructions found in the tutorial listed below.

Windows Vista users can use their Windows CD to boot up into the Vista Recovery Environment.

If on the other hand, you use Windows XP and do not have the Windows CD, ComboFix includes a method of installing the Windows Recovery console by downloading a file from Microsoft. To install the Windows Recovery Console when you do not have the Windows XP CD, please follow these instructions:

  1. Click on the following link to go to Microsoft's Web site:

  2. At that page, scroll down and click on the appropriate download for your version of Windows XP (Home or Professional) and the service pack level that you have installed. When you click on the link to download the file, make sure you save it directly to your desktop. If you are unsure what version of Windows you have and what Service Pack is installed, you can follow these instructions to gain that information.

    1. Click on the Start button.
    2. Click on the Run menu option.
    3. In the Open: field type the following: sysdm.cpl and then click on the OK button.
    4. A screen will appear showing information about your installation. Under the System:Step 2.

      category you should see your Windows version and the installed Service Pack. When you are done determining this information continue with
  3. Once the Microsoft file has finished downloading, you should drag it on top of the ComboFix icon and let your mouse button go. This is shown in the following image.

  4. ComboFix will now automatically install the Windows Recovery Console onto your computer, which will show up as a new option when booting up your computer. Do not select the Windows Recovery Console option when you start your computer unless requested to by a helper.

Once you have finished installing the Windows Recovery Console, please continue with the rest of the tutorial.

We are almost ready to start ComboFix, but before we do so, we need to take some preventative measures so that there are no conflicts with other programs when running ComboFix. At this point you should do the following:

  • Close all open Windows including this one.
  • Close or disable all running Antivirus, Antispyware, and Firewall programs as they may interfere with the proper running of ComboFix. Instructions on disabling these type of programs can be found in this topic.

Once these two steps have been completed, double-click on the ComboFix icon found on your desktop. Please note, that once you start ComboFix you should not click anywhere on the ComboFix window as it can cause the program to stall. In fact, when ComboFix is running, do not touch your computer at all and just take a break as it may take a while for it to complete.

Once you double-click on the icon, you may see a screen similar to the one below.

Windows Open File Security Warning
Windows Open File Security Warning

Windows is issuing this prompt because ComboFix does not have a digital signature. This is perfectly normal and safe and you can click on the Run button to continue. If you are using Windows Vista, and receive UAC prompt asking if you would like to continue running the program, you should press the Continue button. You will now see the first ComboFix screen as shown below.

ComboFix is Preparing to Run
ComboFix is Preparing to Run

ComboFix is now preparing to run and when it has finished you will see the Disclaimer screen shown below.

ComboFix Disclaimer
ComboFix Disclaimer

If you do not agree to the disclaimer, then press the number 2 key on your keyboard and then press enter to exit the program. Otherwise, to continue you should press the number 1 key and then press the enter key to continue. If you decided to continue, then ComboFix will create a System Restore point so that if any problems occur while using the program you can restore back to your previous configuration. When ComboFix has finished creating the restore point, it will then backup your Windows Registry as shown in the image below.

ComboFix is backing up the Windows Registry
ComboFix is backing up the Windows Registry

Once the Windows Registry has finished being backed up, ComboFix will disconnect your computer from the Internet. Therefore, do not be surprised or concerned if you receive any warnings stating that you are no longer on the Internet as your connection will be completely restored at a later stage in the program.

ComboFix will now start scanning your computer for known infections. This procedure can take some time, so please be patient.

ComboFix is scanning the computer for infections
ComboFix is scanning the computer for infections

While the program is scanning your computer, it will change your clock format, so do not be concerned when you see this happen. When ComboFix is finished it will restore your clock settings to what they were previously. You will also see the text in the ComboFix window being updated as it goes through the various stages of its scan. An example of this can be seen below.

Stages of the ComboFix AutoScan
Stages of the ComboFix AutoScan

At the time of this writing there are a total of 41 stages as shown in the image below, so please be patient.

41st Stage of the ComboFix AutoScan
41st Stage of the ComboFix AutoScan

When ComboFix has finished running, you will see a screen stating that it is preparing the log report as shown below.

ComboFix is preparing the log report
ComboFix is preparing the log report

This can take a while, so please be patient. If you see your Windows desktop disappear, do not worry. This is normal and ComboFix will restore your desktop before it is finished. Eventually you will see a new screen that states the program is almost finished and telling you the programs log file, or report, will be located at C:\ComboFix.txt. This can be seen in the image below.

ComboFix is almost done!
ComboFix is almost done!

When ComboFix has finished, it will automatically close the program and change your clock back to its original format. It will then display the log file automatically for you as shown below.

ComboFix Log File
ComboFix Log File

You should now register an account at one of the forums listed below and copy and paste the above log file along with a HijackThis log into a new topic. When posting this information please also provide a description of the problems that you are having. When posting your log files, please be patient as these forums are very active and it could take some time before you receive a response. If you having problems connecting to the Internet after running Combofix, then please see this section.

It is possible that ComboFix, even on its first run, may have fixed the problems you are having. We strongly suggest that you still post your log at a forum as you most likely will have infections left over that a helper will need to analyze further.

Forums to receive help analyzing ComboFix logs

Below is a list of forums that you can post a ComboFix log and receive authorized help analyzing it. We have categorized the forums by language as ComboFix is used internationally. Please register an account and post your ComboFix log in one of these forums along with a HijackThis log. Please note that each forum has different policies, so please be sure to read any pinned topics and rules for the particular forum about how you should go about receiving help.

English Forums
Bleeping Computer Tech Support Forum
CastleCops GeeksToGo
SpywareInfo SpywareWarrior
Dell Community SpyKiller
DSLReports Safer-Networking
WhatTheTech Tech Support Guy
D-A-L SpyWare BeWare
PCPitstop CyberTechHelp
Security Forums ThatComputerGuy
MalwareRemoval Webuser
Gladiator Security MajorGeeks

TeMerc Internet Countermeasures Security Cadets

Dutch Forums
German Forums
Blue Medicine
AntiSpywareOffensief PCMasters CastleCops
Spanish Forums
Portuguese Forums
French Forums
Malekal Spywarefri

Manually restoring the Internet connection

If, by some chance, you no longer have access to your Internet connection after running ComboFix then the first thing to try is to reboot your computer. This step alone should fix the vast majority of issues with no Internet connection after running ComboFix. If you still do not have an Internet connection after rebooting then please perform the following steps:

  1. Click on the Start button.
  2. Click on the Settings menu option.
  3. Click on the Control Panel option.
  4. When the Control Panel opens, double-click on the Network Connections icon. If your Control Panel is set to Category View, then double-click on Network and Internet Connections and then click on Network Connections at the bottom.
  5. You will now see a list of available network connections. Locate the connection for your Wireless or Lan adapter and right-click on it.
  6. You will now see a menu similar to the image below. Simply click on the Repair menu option.

    Repair Internet Connection
    Repair Internet Connection

  7. Let the repair process perform its tasks and when it has finished, your Internet connection should be working again.

Alternatively, if your network icon also appears on the Windows taskbar, then you can repair it by right-clicking on the icon and selecting Repair as shown below.

Repair Internet connection via Tray Icon
Repair Internet connection via Tray Icon

If you still do not have an Internet connection after performing these two tasks, then you may want to ask for help in our forums.

Author: Lawrence Abrams
January 4, 2008 3:55 PM

This article is published and created for, otherwise known as Bleeping Computer, and is covered by all copyright laws. All articles on this web site are copyright © 2003-2008 by Bleeping Computer, LLC. All right reserved. Use of these articles is limited to viewing and printing for personal use only. If you would like to use this material or portions of this material for other purposes you must receive explicit permission from Bleeping Computer before reprinting or redistributing this article in any medium. ComboFix is copyrighted to sUBs.

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