How To Remove MSIL/Kostioul.A Effectively From PC


This Guide has been prepared for providing a comprehensive study about a newly found malware named as MSIL/Kostioul.A. This malware pertains to the Trojan class. It after infiltrating inside the PC creates severe issues regarding its function. It disables the security mechanism of the infected PC and turns it even more vulnerable to infection. Here we provide quick and easy removal strategy to overwhelm attack of such malware.

Worthy facts to about  MSIL/Kostioul.A

​MSIL/Kostioul.A is a dangerous Trojan which gets inside PC taking the assistance of misleading tactics. Such virus spreads through the junk mails, contaminated removal  drives and online share of files and viewing the compromised websites. when this malware succeeds in making space inside PC then day by day it takes PC in severe condition. Users may observe the various changes from ts own  level. Further it introduces the files named as %ProgramFiles%\windowslive\windowsupadate.exe and %TEMP%\rarsfx0\yuyhrd.exe. Moreover it drops the manipulation in the windows registry to enable itself to execute its functionality in automatic way. The  most challenging characteristics is that it inserts a escaping code which turns even more harder to find out its presence inside PC. This Trojan is designed to make collection of  sensitive information without user's permission. Those information may include the program that is being opened, the data concerned with browsing activities, the particular key that is being tapped, details related with credit card and user names and password. Sometime it copies the authentic web sites to convince users to unfold their personal information. Aside from these, it establishes the remote association which includes the using port 53.  it  mainly  carries the motive of  collecting information from its developers, intimate about the new threat to the hackers or monitor the Internet connection. MSIL/Kostioul.A  also possess the potential for creating the mutexes on compromised PC.

How MSIL/Kostioul.A gets inside PC?

Though MSIL/Kostioul.A  is developed by cyber hackers who aim at earning  the   profit on illegal basis or arising  deceiving users by showing fake message alerts. Such Trojan is usually injected inside PC through the attachments along with Junk mails. Most often attachments are introduced in the mask of legitimate document. Apart from this, it creator hides this inside the advance and Custom installation as it is well known to them that users most of the time prefer to ignore this. Users possess the eagerness to view the unknown websites as and opening the links which at random appears before them.  All these  steps makes their PC compromised or more endangered to get infected. 

What trouble are caused by MSIL/Kostioul.A?

  • MSIL/Kostioul.A arises various issues after getting installed inside PC.
  • It inserts the file which can be identified with name as %ProgramFiles%\windowslive\windowsupadate.exe.
  • Users may observe the unwanted changes in the Windows registry which is done for creating a ground for self activation of this Trojan at every launch of system.
  • It makes utilization of code injection to keep itself undetected  for longer time inside PC. 
  • It moreover makes connection with remote host to provide information about the new infection to its author.
  • It also makes the theft of sensitive information of users which may be later used to fulfill some other evil task.
  • It also  introduces its mutexes inside the targeted PC.

Recommendation by researchers for MSIL/Kostioul.A

Researchers strongly recommend the instant deletion of  MSIL/Kostioul.A from PC as its may turn PC even more vulnerable and take into the condition of  being non worthy for anything. As it keeps gathering the sensitive information so it is certain that it is capable of stealing even the money from victims  bank account. Users may take the immediate action for its removal by trying the mentioned manual removal tips in this article.    

Name MSIL/Kostioul.A
Type Trojan
Symptoms It after getting inside PC alters the Windows registry and collects the sensitive information of users.
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MSIL/Kostioul.A Removal Process



Disable System Restore: Trojan has habit of infecting your system restore points, which can result in continuous infection, even after it is removed.

open system properties >> system protection >> click configure button >> Disable system protection & delete all system restore points. (see in pic below)


once trojan is removed you can re-enable system restore.


Reboot your system in safe mode (Read the tutorial how to boot in safe mode if you don’t know)


Un check all hidden files and folder properties (Know how to do it)

This is important as the MSIL/Kostioul.A may be hidden it’s files.

Pres Windows+R key to open search field


Type msconfig and hit to open system configuration tab


In startup browse through list of programs and uncheck suspicious/unwanted programs from the list.

Press Windows+ R key to open search field
Type appwiz.cpl and press ok


you are now at control panel > add remove program: Remove any suspicious program.




Check your host file , if it is hijacked by MSIL/Kostioul.A trojan

Pres Windows+R key to open search field

Type : “notepad %windir%/system32/Drivers/etc/hosts” hit enter

A file will open and if you are hijacked a new ip or bunch of ip’s will appear on the bottom of the page. You can see it in the image below.


if you are hijacked follow the Microsoft link to reset the infected host file.



Press ctrl+shift+esc to go into windows task manager. There click the processes tab and look out for any suspicious process or virus


if you find any process related to MSIL/Kostioul.A you can right click and “open file location”. once file location is opened you can kill the process there and all the directories from the folder you were sent to.

For your Convenience, You need to work Cautiously: Read Alertwarning1


Type Regedit in windows search field.

Once its open click ctrl+F and search for the threat name. If its found then right click and delete its entries.


Kindly write to us if you need furthur help.