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Cosd Virus File Removal

What Is Cosd Virus?

COSD Ransomware Virus Removal Recovery Guide

Cosd infection is the name of popular ransomware, that originates from the STOP/DJVU family of threats. This shows that it is a cryptovirus, that intends to encrypt your vital files and after that use them against you to urge you into making a payment to the hackers that have infected you with it. The ransom demands (written in the _readme.txt data) of Cosd infection intend to convince you into paying BitCoin or other kinds of cryptocurrencies and the crooks give a deadline after which the cost can increase or you risk losing your files.

At first, this virus modifies the system files of Windows to make it possible that it can evade being detected and also encode files while uninterrupted by anti-malware applications. By including values and data in the RUN or RUNONCE computer registry sub-keys in the Windows RegEdit, the Cosd infection can start on your computer every single time you press the power-on button.

Cosd Summary

Name Cosd also known as Trojan.GenericKD.35978248, Trojan.Win32.Stop.j!c, Trojan.Ransom.Stop, Trojanransom.Stop, A Variant Of Win32/Kryptik.HIMQ, Trojan-Ransom.Win32.Stop.qq
File Extension .cosd
Type Ransomware, Cryptovirus
Short Description The ransomware encrypts files on your computer system and demands ransom to be paid to allegedly recover them.
Symptoms This variant of STOP ransomware will encrypt your files by appending the .cosd extension to them.
Ransom Demanding Note _readme.txt
Distribution Method Spam Emails, Email Attachments, Torrent Files
Detection Tool See If Your System Has Been Affected by malware


Malware Removal Tool

Cosd Ransomware Infection – More Information

Cosd infection is ransomware that affects Windows computer systems and is probably the infection you want to see.

Hackers are believed to depend on techniques like spam e-mails, attached files, hacked sites, or damaged free app installers for the spread of their hazardous Cosd infection. As a result of the malspam being a reliable technique that permits hackers to spread their infection files utilizing huge e-mail spam campaigns, they usually pick other innovative and new ways to send the e-mails.

One of the most commonly used files, utilized by malware are executable ones, self-extractors, or different other Microsoft Office files, applications, scripts, PDFs, etc.

When this partiuclar infection becomes active, it might download its infection files to the victim PC. They may be located under different, often random names in the following folders:

  • %AppData%
  • %LocalLow%
  • %Temp%
  • %ProgramData%
  • %Windows%
  • %System%
  • %system32%
  • %Roaming%
  • %Local%

The Cosd infection has the ability to infect your Windows OS using 2 primary methods:

  • If the file is masked as an app offered free for download online, but instead of a free app, you download and run the infection.
  • If it is sent to you as e-mail documents that claim to be legitimate, like invoices, aircraft tickets, and others.

As soon as the infection is downloaded and ran, the virus begins to do these tasks on your computer:

  • Run as administator.
  • Obtain read and write authorizations.
  • Analyze If it has infected your computer system previously and if so deletes itself.
  • Establish a connection with the cyber-criminals running it.
  • Creating Windows registry entries in the “Run” or “RunOnce” Registry sub-keys.

The primary job of Cosd infection is revolved around encrypting your important data. The infection scans for and encrypts the following kind of file types while adding its own extension:

  • Videos.
  • Pictures.
  • Docs.
  • Music.
  • Databases.
  • Archives.
  • Anything conserved in a USB or other drive.
  • Back-ups.

When the Cosd virus has encoded your files, it creates a one-of-a-kind decryption secret that can be used with a decryptor to decipher your files. Sadly, the cyber-criminals who are behind Cosd infection conceal this decryptor because they want you to pay money or BitCoin to guarantee that they can send you decryption. Their demands are well written in the _readme.txt ransom file, situated by this infection on your system. It has the following message:

Cosd ransomware virus ransom message

The Cosd virus aims to encode the files including the .cosd file extension, making it easier to be detected. If you remove this extension, you will NOT repair the file, so refrain from doing it, due to the fact that you take the chance of risking your files.

The files that have the .cosd suffix can not be opened because they are encoded. Ransomware infections, like Cosd virus, are a part of the STOP/DJVU family of crypto-malware. They are taking advantage of a very particular security “algorithm”, called Advanced Encryption Standard. This cipher also abbreviated as AES encrypts data and modifies info in the original files, creating an asymmetric decryption key.

The cipher can be incredibly challenging to decrypt even by a supercomputer. The only method to decrypt it is if you identify the decryption on your own. Typically, cyber-security researchers, like Michael Gillespie and also the specialists at Emsisoft deal with STOP Ransomware, and sometimes when there is a new Cosd infection, they manage to trick the virus encryption and create a free decryptor for the latest versions of this infection.

Nonetheless, remember that the Cosd virus files can be decrypted simply if the decryption key that is generated is the Offline kind. For the Online type of key, decryption along with data recovery is substantially more difficult than normal.

Remove Cosd Virus and Try to Restore Files

To get rid of Cosd virus, you need to follow the steps below. They are made to aid you to remove the Cosd ransomware effectively. If you do not know where specifically are the infection files located, you can download and run a scan with professional anti-malware software to delete this threat. Such a program will scan for the ransomware virus files on your computer and make sure that the files are gotten rid of. For the recovery, the only choices we have are recommended in the “recovery” steps listed below. They might not be a 100% fix, however, with them you have some hope of getting back some documents until a decryptor appears for the Cosd infection. In the meantime, we at SensorsTechForum.com would advise that you backup your data till malware researchers release a decryptor.

Ventsislav Krastev

Ventsislav is a cybersecurity expert at SensorsTechForum since 2015. He has been researching, covering, helping victims with the latest malware infections plus testing and reviewing software and the newest tech developments. Having graduated Marketing as well, Ventsislav also has passion for learning new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management, Network Administration and Computer Administration of System Applications, he found his true calling within the cybersecrurity industry and is a strong believer in the education of every user towards online safety and security.

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Attention! SensorsTechForum strongly recommends that all malware victims should look for assistance only by reputable sources. Many guides out there claim to offer free recovery and decryption for files encrypted by ransomware viruses. Be advised that some of them may only be after your money.

As a site that has been dedicated to providing free removal instructions for ransomware and malware since 2014, SensorsTechForum’s recommendation is to only pay attention to trustworthy sources.

How to recognize trustworthy sources:

  • Always check "About Us" web page.
  • Profile of the content creator.
  • Make sure that real people are behind the site and not fake names and profiles.
  • Verify Facebook, LinkedIn and Twitter personal profiles.


with Anti-Malware
We recommend you to download SpyHunter and run free scan to remove all virus files on your PC. This saves you hours of time and effort compared to doing the removal yourself.
SpyHunter 5 free remover allows you, subject to a 48-hour waiting period, one remediation and removal for results found. Read EULA and Privacy Policy

Windows Mac OS X

How to Remove Cosd Virus from Windows.

Step 1: Boot Your PC In Safe Mode to isolate and remove Cosd Virus


Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!
We Recommend To Scan Your PC with SpyHunter

Keep in mind, that SpyHunter’s scanner is only for malware detection. If SpyHunter detects malware on your PC, you will need to purchase SpyHunter's malware removal tool to remove the malware threats. Read our SpyHunter 5 review. Click on the corresponding links to check SpyHunter's EULA, Privacy Policy and Threat Assessment Criteria

1. Hold Windows key() + R

2. The "Run" Window will appear. In it, type "msconfig" and click OK.

3. Go to the "Boot" tab. There select "Safe Boot" and then click "Apply" and "OK".
Tip: Make sure to reverse those changes by unticking Safe Boot after that, because your system will always boot in Safe Boot from now on.

4. When prompted, click on "Restart" to go into Safe Mode.

5. You can recognise Safe Mode by the words written on the corners of your screen.

Step 2: Uninstall Cosd Virus and related software from Windows

Here is a method in few easy steps that should be able to uninstall most programs. No matter if you are using Windows 10, 8, 7, Vista or XP, those steps will get the job done. Dragging the program or its folder to the recycle bin can be a very bad decision. If you do that, bits and pieces of the program are left behind, and that can lead to unstable work of your PC, errors with the file type associations and other unpleasant activities. The proper way to get a program off your computer is to Uninstall it. To do that:

1. Hold the Windows Logo Button and "R" on your keyboard. A Pop-up window will appear.

2. In the field type in "appwiz.cpl" and press ENTER.

3. This will open a window with all the programs installed on the PC. Select the program that you want to remove, and press "Uninstall"
Follow the instructions above and you will successfully uninstall most programs.

Step 3: Clean any registries, created by Cosd Virus on your computer.

The usually targeted registries of Windows machines are the following:

  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

You can access them by opening the Windows registry editor and deleting any values, created by Cosd Virus there. This can happen by following the steps underneath:

1. Open the Run Window again, type "regedit" and click OK.

2. When you open it, you can freely navigate to the Run and RunOnce keys, whose locations are shown above.

3. You can remove the value of the virus by right-clicking on it and removing it.
Tip: To find a virus-created value, you can right-click on it and click "Modify" to see which file it is set to run. If this is the virus file location, remove the value.

Before starting "Step 4", please boot back into Normal mode, in case you are currently in Safe Mode.
This will enable you to install and use SpyHunter 5 successfully.

Step 4: Scan for Cosd Virus with SpyHunter Anti-Malware Tool

1. Click on the "Download" button to proceed to SpyHunter's download page.

It is recommended to run a scan before purchasing the full version of the software to make sure that the current version of the malware can be detected by SpyHunter. Click on the corresponding links to check SpyHunter's EULA, Privacy Policy and Threat Assessment Criteria.

2. After you have installed SpyHunter, wait for it to update automatically.


3. After the update process has finished, click on the 'Malware/PC Scan' tab. A new window will appear. Click on 'Start Scan'.


4. After SpyHunter has finished scanning your PC for any files of the associated threat and found them, you can try to get them removed automatically and permanently by clicking on the 'Next' button.


If any threats have been removed, it is highly recommended to restart your PC.

Step 5 (Optional): Try to Restore Files Encrypted by Cosd Virus.

Ransomware infections and Cosd Virus aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested a data recovery method that may help you go around direct decryption and try to restore your files. Bear in mind that this method may not be 100% effective but may also help you a little or a lot in different situations.

1. Download the reccomended Data Recovery software by clicking on the link underneath:

Simply click on the link and on the website menus on top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.

Windows Mac OS X

Get rid of Cosd Virus from Mac OS X.

Step 1: Uninstall Cosd Virus and remove related files and objects

Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!
We Recommend To Scan Your Mac with SpyHunter for Mac
Keep in mind, that SpyHunter for Mac needs to purchased to remove the malware threats. Click on the corresponding links to check SpyHunter’s EULA and Privacy Policy

1. Hit the ⇧+⌘+U keys to open Utilities. Another way is to click on “Go” and then click “Utilities”, like the image below shows:

2. Find Activity Monitor and double-click it:

3. In the Activity Monitor look for any suspicious processes, belonging or related to Cosd Virus:

Tip: To quit a process completely, choose the “Force Quit” option.

4. Click on the "Go" button again, but this time select Applications. Another way is with the ⇧+⌘+A buttons.

5. In the Applications menu, look for any suspicious app or an app with a name, similar or identical to Cosd Virus. If you find it, right-click on the app and select “Move to Trash”.

6: Select Accounts, after which click on the Login Items preference. Your Mac will then show you a list of items that start automatically when you log in. Look for any suspicious apps identical or similar to Cosd Virus. Check the app you want to stop from running automatically and then select on the Minus (“-“) icon to hide it.

7: Remove any left-over files that might be related to this threat manually by following the sub-steps below:

  • Go to Finder.
  • In the search bar type the name of the app that you want to remove.
  • Above the search bar change the two drop down menus to “System Files” and “Are Included” so that you can see all of the files associated with the application you want to remove. Bear in mind that some of the files may not be related to the app so be very careful which files you delete.
  • If all of the files are related, hold the ⌘+A buttons to select them and then drive them to “Trash”.

In case you cannot remove Cosd Virus via Step 1 above:

In case you cannot find the virus files and objects in your Applications or other places we have shown above, you can manually look for them in the Libraries of your Mac. But before doing this, please read the disclaimer below:

Disclaimer! If you are about to tamper with Library files on Mac, be sure to know the name of the virus file, because if you delete the wrong file, it may cause irreversible damage to your MacOS. Continue on your own responsibility!

1: Click on "Go" and Then "Go to Folder" as shown underneath:

2: Type in "/Library/LauchAgents/" and click Ok:

3: Delete all of the virus files that have similar or the same name as Cosd Virus. If you believe there is no such file, do not delete anything.

You can repeat the same procedure with the following other Library directories:

→ ~/Library/LaunchAgents

Tip: ~ is there on purpose, because it leads to more LaunchAgents.

Click the button below below to download SpyHunter for Mac and scan for Cosd Virus:


SpyHunter for Mac

Step 3 (Optional): Try to Restore Files Encrypted by Cosd Virus.

Ransomware infections and Cosd Virus aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested a data recovery method that may help you go around direct decryption and try to restore your files. Bear in mind that this method may not be 100% effective but may also help you a little or a lot in different situations.

1. Download the reccomended Data Recovery software by clicking on the link underneath:

Simply click on the link and on the website menus on top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.

Cosd Virus FAQ

What is Cosd Virus ransomware and how does it work?

Cosd Virus is a ransomware infection - the malicious software that enters your computer silently and blocks either access to the computer itself or encrypt your files.

Many ransomware viruses use sophisticated encryption algorithm how to make your files inaccessible. The goal of ransomware infections is to demand that you pay a ransom payment to get access to your files back.

How does Cosd Virus ransomware infect my computer?

Via several ways.Cosd Virus Ransomware infects computers by being sent via phishing e-mails, containing virus attachment.

This attachment is usually masked as an important document, like an invoice, bank document or even a plane ticket and it looks very convincing to users.

After you download and execute this attachment, a drive-by download occurs and your computer is infected with the ransomware virus.

Another way, you may become a victim of Cosd Virus is if you download a fake installer, crack or patch from a low reputation website or if you click on a virus link. Many users report getting a ransomware infection by downloading torrents.

How to open .Cosd Virus files?

You can't. At this point the .Cosd Virus files are encrypted. You can only open them once they are decrypted.

Decryptor did not decrypt my data. What now?

Do not panic and backup the files. If a decryptor did not decrypt your .Cosd Virus files successfully, then do not despair, because this virus is still new.

One way to restore files, encrypted by Cosd Virus ransomware is to use a decryptor for it. But since it's a new virus, advised that the decryption keys for it may not be out yet and available to the public. We will update this article and keep you posted as soon as this decryptor is released.

How Do I restore ".Cosd Virus" files (Other Methods)?

Yes, sometimes files can be restored. We have suggested several file recovery methods that could work if you want to restore .Cosd Virus files.

These methods are in no way 100% guarantee that you will be able to get your files back. But if you have a backup, your chances of success are much greater.

How do I get rid of Cosd Virus ransomware virus?

The safest way and the most efficient one for the removal of this ransomware infection is the use a professional anti malware software. It will scan for and locate Cosd Virus ransomware and then remove it without causing any additional harm to your important .Cosd Virus files.

Also, keep in mind that viruses like Cosd Virus ransomware also install Trojans and keyloggers that can steal your passwords and accounts. Scanning your computer with an anti-malware software will make sure that all of these virus components are removed and your computer is protected in the future.

What to Do If nothing works?

There is still a lot you can do. If none of the above methods seem to work for you, then try these methods:

  • Try to find a safe computer from where you can can login on your own line accounts like One Drive, iDrive, Google Drive and so on.
  • Try to contact your friends, relatives and other people so that they can check if they have some of your important photos or documents just in case you sent them.
  • Also, check if some of the files that were encrypted it can be re-downloaded from the web.
  • Another clever way to get back some of your files is to find another old computer, a flash drive or even a CD or a DVD where you may have saved your older documents. You might be surprised what will turn up.
  • You can also go to your email account to check if you can send any attachments to other people. Usually what is sent the email is saved on your account and you can re-download it. But most importantly, make sure that this is done from a safe computer and make sure to remove the virus first.

More tips you can find on our forums, where you can also asks any questions about your ransomware problem.

How to Report Ransomware to Authorities?

In case your computer got infected with a ransomware infection, you can report it to the local Police departments. It can help authorities worldwide track and determine the perpetrators behind the virus that has infected your computer. Below, we have prepared a list with government websites, where you can file a report in case you are a victim of a cybercrime:

Cyber-security authorities, responsible for handling ransomware attack reports in different regions all over the world:

Reports may be responded to in different timeframes, depending on your local authorities.

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