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Cosacos Virus Files (Ransomware) – How to Remove It

What are .cosacos files? How to open .cosacos encrypted file? How to remove Cosacos ransomware virus and try to recover .cosacos files?

Yet another variant of the notorious STOP ransomware family of viruses has resurfaced carrying the name Cosacos. The main objective of these viruses is to encrypt the files on your computer and hold them hostage until you pay ransom in BitCoin to get them to work again. Read this article to understand how you can remove the Cosacos virus and how you can try and restore your files.

Threat Summary

Name Cosacos Virus
Type Ransomware, Cryptovirus
Short Description A cryptovirus that encodes your files and wants you to pay a big ransom in order to get the encrypted files to work again.
Symptoms Files have the .cosacos extension. The virus also shows a ransom note, called _readme.txt.
Distribution Method Spam Emails, Email Attachments, Executable files
Detection Tool See If Your System Has Been Affected by malware

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User Experience Join Our Forum to Discuss Cosacos Virus.
Data Recovery Tool Windows Data Recovery by Stellar Phoenix Notice! This product scans your drive sectors to recover lost files and it may not recover 100% of the encrypted files, but only few of them, depending on the situation and whether or not you have reformatted your drive.

Cosacos Virus – Update August 2019

The good news for all victims of STOP Cosacos ransomware is that the security researcher Michael Gillespie found weaknesses in the code of this variant and released an updated version of his STOP ransomware decrypter.

So the moment you remove all malicious files and objects from your infected system you can enter our data recovery guide where you will find a download link for the free Cosacos decryption tool and learn how to proceed with the decryption process.

[wplinkpreview url=”https://sensorstechforum.com/decrypt-files-stop-ransomware/”] Decrypt Files Encrypted by STOP Ransomware

Have in mind that the tool is designed to support specific offline IDs, so it may not be effective for all occasions of Cosacos virus ransomware infections.

Cosacos Virus – How Did I Get It and What Does It Do?

Cosacos virus may enter your computer in a variety of ways, the main of which could be having the virus files uploaded online. The Cosacos virus can be uploaded on several suspicious websites, where it may pretend to be a completely legitimate type of setup, program, patch, portable software, crack or key generator. The main idea is for victims to get tricked into downloading and running the virus file, which when executed exploits weaknesses in your computer in order to make a silent infection.

When the Cosacos virus is added to your computer, it may immediately show its presence by obtaining administrator rights and starting to encrypt your files. The files that are encrypted by the Cosacos virus are with the following file extension:

Not only this, but the Cosacos virus also drops a ransom note on victimized computers and this note aims to threaten you that there is a risk for you to never see your files again if you do not pay the hackers behind the Cosacos virus ransom in BitCoin. The note is named _readme.txt and it has the following contents:

ATTENTION!

Don’t worry my friend, you can return all your files!
All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you. This software will decrypt all your encrypted files. What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool: https://we.tl/t-1aaC7npeV9 Price of private key and decrypt software is $980. Discount 50% available if you contact us first 72 hours, that’s price for you is $490. Please note that you’ll never restore your data without payment. Check your e-mail “Spam” folder if you don’t get answer more than 6 hours.
To get this software you need write on our e-mail: blower@india.com
Reserve e-mail address to contact us: blower@firemail.cc Your personal ID:

If you have been infected by the Cosacos version of STOP Ransomware we strongly recommend that you not pay the ransom and backup all of the .cosacos files so that you can restore them for free later on, when a decryptor comes out. For this family of viruses, a decryptor takes about a week time to be released by malware researchers and it can get your files back absolutely for free.

Remove Cosacos Virus and Try to Restore .cosacos Encrypted Files

If you want Cosacos ransomware completely gone from your computer, we do recommend that you read the instructions underneath this article. They have been created to help you to remove this virus step by step from your computer. If you cannot manually find and delete all Cosacos virus files, then do not worry, because you can remove them automatically. According to security experts, the most reccommended type of removal is if you download and run a scan of your computer by using an advanced anti-malware software. This program will effectively make sure to thoroughly detect and eliminate all Cosacos virus files and protect your machine in the future as well.

Not only this, but to restore files, encrypted by the Cosacos virus, we suggest that you also check out the alternative methods for file recovery below. They may not come with a 100% file restore guarantee, but with their aid you may be able to restore some of them at least.

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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  • Step 5

Step 1: Scan for Cosacos 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.

scan for and delete ransomware virus step 2


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

scan for and delete ransomware virus step 3


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.

scan for and delete ransomware virus step 4

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

Ransomware Automatic Removal - Video Guide

Step 2: Uninstall Cosacos Virus and related malware 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.
delete ransomware from windows step 1


2. In the field type in "appwiz.cpl" and press ENTER.
delete ransomware from windows step 2


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"
delete ransomware from windows step 3Follow the instructions above and you will successfully delete most unwanted and malicious programs.


Step 3: Clean any registries, created by Cosacos 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 Cosacos Virus there. This can happen by following the steps underneath:

1. Open the Run Window again, type "regedit" and click OK.
delete ransomware virus registries step 1


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


3. You can remove the value of the virus by right-clicking on it and removing it.
delete ransomware virus registries step 3 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.

IMPORTANT!
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: Boot Your PC In Safe Mode to isolate and remove Cosacos Virus

OFFER

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.
remove ransomware in safe mode step 1


2. The "Run" Window will appear. In it, type "msconfig" and click OK.
remove ransomware in safe mode step 2


3. Go to the "Boot" tab. There select "Safe Boot" and then click "Apply" and "OK".
remove ransomware in safe mode step 3
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.
remove ransomware in safe mode step 4


5. You can recognise Safe Mode by the words written on the corners of your screen.
remove ransomware in safe mode step 5


Step 5: Try to Restore Files Encrypted by Cosacos Virus.

Method 1: Use STOP Decrypter by Emsisoft.

Not all variants of this ransomware can be decrypted for free, but we have added the decryptor used by researchers that is often updated with the variants which become eventually decrypted. You can try and decrypt your files using the instructions below, but if they do not work, then unfortunately your variant of the ransomware virus is not decryptable.

Follow the instructions below to use the Emsisoft decrypter and decrypt your files for free. You can download the Emsisoft decryption tool linked here and then follow the steps provided below:

1 Right-click on the decrypter and click on Run as Administrator as shown below:

stop ransomware decryptor step 1

2. Agree with the license terms:

stop ransomware decryptor step 2

3. Click on "Add Folder" and then add the folders where you want files decrypted as shown underneath:

stop ransomware decryptor step 3

4. Click on "Decrypt" and wait for your files to be decoded.

stop ransomware decryptor step 4

Note: Credit for the decryptor goes to Emsisoft researchers who have made the breakthrough with this virus.

Method 2: Use data recovery software

Ransomware infections and Cosacos 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 recommended Data Recovery software by clicking on the link underneath:

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


Cosacos Virus-FAQ

What is Cosacos Virus Ransomware?

Cosacos 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 algorithms 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.

What Does Cosacos Virus Ransomware Do?

Ransomware in general is a malicious software that is designed to block access to your computer or files until a ransom is paid.

Ransomware viruses can also damage your system, corrupt data and delete files, resulting in the permanent loss of important files.

How Does Cosacos Virus Infect?

Via several ways.Cosacos Virus Ransomware infects computers by being sent via phishing emails, 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.

Another way you may become a victim of Cosacos 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 .Cosacos Virus files?

You can't without a decryptor. At this point, the .Cosacos Virus files are encrypted. You can only open them once they are decrypted using a specific decryption key for the particular algorithm.

What to Do If a Decryptor Does Not Work?

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

Can I Restore ".Cosacos Virus" Files?

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

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

How To Get Rid of Cosacos Virus Virus?

The safest way and the most efficient one for the removal of this ransomware infection is the use a professional anti-malware program.

It will scan for and locate Cosacos Virus ransomware and then remove it without causing any additional harm to your important .Cosacos Virus files.

Can I 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:

Germany - Offizielles Portal der deutschen Polizei

United States - IC3 Internet Crime Complaint Centre

United Kingdom - Action Fraud Police

France - Ministère de l'Intérieur

Italy - Polizia Di Stato

Spain - Policía Nacional

Netherlands - Politie

Poland - Policja

Portugal - Polícia Judiciária

Greece - Cyber Crime Unit (Hellenic Police)

India - Mumbai Police - CyberCrime Investigation Cell

Australia - Australian High Tech Crime Center

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

Can You Stop Ransomware from Encrypting Your Files?

Yes, you can prevent ransomware. The best way to do this is to ensure your computer system is updated with the latest security patches, use a reputable anti-malware program and firewall, backup your important files frequently, and avoid clicking on malicious links or downloading unknown files.

Can Cosacos Virus Ransomware Steal Your Data?

Yes, in most cases ransomware will steal your information. It is a form of malware that steals data from a user's computer, encrypts it, and then demands a ransom in order to decrypt it.

In many cases, the malware authors or attackers will threaten to delete the data or publish it online unless the ransom is paid.

Can Ransomware Infect WiFi?

Yes, ransomware can infect WiFi networks, as malicious actors can use it to gain control of the network, steal confidential data, and lock out users. If a ransomware attack is successful, it could lead to a loss of service and/or data, and in some cases, financial losses.

Should I Pay Ransomware?

No, you should not pay ransomware extortionists. Paying them only encourages criminals and does not guarantee that the files or data will be restored. The better approach is to have a secure backup of important data and be vigilant about security in the first place.

What Happens If I Don't Pay Ransom?

If you don't pay the ransom, the hackers may still have access to your computer, data, or files and may continue to threaten to expose or delete them, or even use them to commit cybercrimes. In some cases, they may even continue to demand additional ransom payments.

Can a Ransomware Attack Be Detected?

Yes, ransomware can be detected. Anti-malware software and other advanced security tools can detect ransomware and alert the user when it is present on a machine.

It is important to stay up-to-date on the latest security measures and to keep security software updated to ensure ransomware can be detected and prevented.

Do Ransomware Criminals Get Caught?

Yes, ransomware criminals do get caught. Law enforcement agencies, such as the FBI, Interpol and others have been successful in tracking down and prosecuting ransomware criminals in the US and other countries. As ransomware threats continue to increase, so does the enforcement activity.

About the Cosacos Virus Research

The content we publish on SensorsTechForum.com, this Cosacos Virus how-to removal guide included, is the outcome of extensive research, hard work and our team’s devotion to help you remove the specific malware and restore your encrypted files.


How did we conduct the research on this ransomware?

Our research is based on an independent investigation. We are in contact with independent security researchers, and as such, we receive daily updates on the latest malware and ransomware definitions.

Furthermore, the research behind the Cosacos Virus ransomware threat is backed with VirusTotal and the NoMoreRansom project.

To better understand the ransomware threat, please refer to the following articles which provide knowledgeable details.


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.

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