My computer got a Trojan virus yesterday . MSE report it as TrojanDropper:Win32/Sirefef.B. I don’t know why my antivirus can’t remove it. I just found the path of the virus and removed it but after I restarted my computer later, It came back. And the MSE kept reporting that my computer has the virus. I’m really confused. Is that just report or I have already removed the virus. Do I need to worry about the case?

TrojanDropper:Win32/Sirefef.B Introduction

Win32/Sirefef.B is a destructive Trojan virus that has been detected in PC users’ computers. a dropper Trojan contains malicious or potentially unwanted software which it ‘drops’ and installs on the affected system. Commonly, the dropper installs a backdoor which allows remote, surreptitious access to infected systems. This backdoor may then be used by remote attackers to upload and install further malicious or potentially unwanted software on the system. This threat is detected by the Microsoft antivirus engine. It’s indeed a component of some malware that can moderates your Internet experience and some previous settings so that you can’t use some programs in your computer.

Anti-virus can remove most of viruses but if some virus make use of the weakness of the operating system or anti-virus itself, they can’t be removed automatically by anti-virus. Win32/Sirefef.B may keep changing its name randomly so that your anti-virus can’t remove it. Or it will camouflage as the system file. In this way, the anti-virus won’t easily remove it. The most awful and destructive action of the virus is that some Trojan virus will start background downloading when it has its full swing without your notice and permission. All those download things always containing viruses as well. Many anti-virus can remove some components of a malware. But if can’t be removed completely, the malware will start its auto recovery. So that’s why more and more viruses are so clever that anti-virus can’t get rid of them.

Tips: If you are not a  computer illiterate and don’t have much experience in this field to remove Win32/Sirefef.B, you can contact YooCare PC Online Service for help here:

What is the Potential Risk of Trojan Virus?

A. Your computer is something not normal as usual such as running very slowly.

B. When you open the Task Manager, you can find some strange processes which you never found before.

C. Some of your computer functions are unavailable or some normal legal program can’t run or there are unusual conditions of them.

D. It always constantly happens that your system has errors somewhere.

E. Later, your computer system will be totally destroyed.

What Is The Best Way to Remove Trojan ?

Depending on which level of risk of the Trojan has infiltrated your PC, you might find it is hard to get rid of this sophisticated worm. Some people have successfully cleaned out the stubborn worm, but since one of the primary functions of this virus is to disable security programs,so the method of using anti-virus program is not always a foolproof approach.

Please follow these steps to get rid of TrojanDropper:Win32/Sirefef.B manually:
Step 1: Press CTRL+ALT+DEL or CTRL+SHIFT+ESC. Open the Windows Task Manager.
If that didn’t work, try another way. Press the Start button and click on the Run option. This will start the Run tool. Type in taskmgr and press OK. This should start the Windows Task Manager

Step 2: Within the Windows Task Manager click on the Processes tab. Find the process by name. random.exe. Then scroll the list to find required process. Select it with your mouse or keyboard and click on the End Process button. This will kill the process.

Step 3: Delete malicious registry entries.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\random
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\run\random

Step 4: Remove malicious files of TrojanDropper:Win32/Sirefef.B

C:\windows\system32\services.exe (randomly named)
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Ext\Settings\{FddsFE4DFF-B2DS54457-AS0902LS99SD}
C:\Program Files\Search Results Toolbar\Datamngr\SRTOOL~1\random

Video of Key Steps on How to Modify or Change Registry to Completely Clean Trojan:

Further more, please be careful when you try to fix TrojanDropper:Win32/Sirefef.B Virus problem yourself. It’s not so easy for one person who is not familiar with the virus and not well trained in IT filed. The virus can change its name constantly which will make the removal work harder to you. If you don’t have much knowledge of Windows operating system, you almost can’t find it out from so large amounts of system files. And you’d better don’t try so called free software to get rid of this Trojan since the virus is well disguised that anti-virus may delete some system files erroneously. What’s more so called free software may be another cheater. You’d better to find an expert to help you remove this Trojan.

Kindly Reminder: If you failed to remove TrojanDropper:Win32/Sirefef.B with the methods you found from the internet, please consult YooSecurity certified professionals to remove it completely.

Published by Leo R. Oscar & last updated on June 30, 2013 3:37 am

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