Remove Cosacos Virus Ransomware (+.Cosacos File Recovery)

The encrypted files may not be the only damage done to you. parasite may still be hiding on your PC. To determine whether you've been infected with ransomware, we recommend downloading SpyHunter.

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This page aims to help you remove Cosacos for free. Our instructions also cover how any .Cosacos file can be recovered.

Attacks from programs that attempt to lock up the users’ data are some of the most common malware-related problems nowadays. On this page, we will talk about one such program, which is called Cosacos, and which belongs to the infamous Ransomware family. This particular infection operates as a file-encrypting virus (or a cryptovirus). There are many techniques that the cybercriminals use to access unprotected systems in order to infect them with Ransomware cryptoviruses, because those threats help them extort money from the unsuspecting web users. They do that by secretly encrypting the personal files stored on the infected machine, and then asking for a ransom payment in exchange for the data’s decryption. If your images, videos, audios, documents and other types of valuable data have been locked by Cosacos, and you have landed on this page seeking help on how to remove the infection, stay with us. Below, you will find a detailed removal guide and a professional removal tool for automatic detection, which may be invaluable in the fight with this harmful computer threat.

How does the .Cosacos file encryption work?

.Cosacos File

These are the infected files by a new strain of the STOP Ransomware, modifying the extension with .Cosacos

A file-encryption is a reliable data-protection method which keeps digital information away from unauthorized access. The encrypted data is accessible only with the help of a corresponding decryption key, which unlocks it. The file-encryption method has wide implementation in many business sectors and in any area where digital information should be kept safe and private. However, people with malicious intentions have found a way to use this otherwise reliable data-protection process in their favor. With the help of infections like Cosacos or Nelasod, they have found a way to secretly encrypt the information stored on the infected machines and then ask the users for a ransom payment in exchange for sending them the decryption key.

Dealing with such an attack can be very challenging. However,  if you don’t immediately fulfill the hacker’s ransom demands, and instead take your time to explore the available alternatives and the legitimate methods which can help you to remove the Ransomware, you may find a working solution.

How to remove the Cosacos virus?

.Cosacos Virus

Read_Me.txt file of .Cosacos Ransomware with instructions for you to follow.

According to experts, Cosacos virus is which spreads through spam emails, seemingly harmless ads, fake pop-ups, and other “social engineering” techniques. Generally, the fake emails distributing such infections tell people about missing payments, fees, purchases, and stuff that can easily lead them to open the malicious attachment that comes in the message. In many cases, the Ransomware may sneak into your computer through fake pop-ups, which claim you need to upgrade a given program or download some update. As soon as you interact with the harmful payload, the computer gets infected. If you want to be safe, you should never trust such messages and always check the suggested updates/downloads with the official developer.

If you get tricked and the infection finds its way inside the system, don’t get panicked. Focus the malware’s removal, and explore alternative file-recovery solutions. Paying the ransom is not advisable and should only be considered if nothing else works.

To avoid losing files due to Ransomware file-encryption in the future, you should also consider a reliable form of protection. The first thing you need to do is download and install a trusted anti-malware program on your computer. In addition, make sure you regularly back up your most important data and store it on an external drive or on a cloud. This way, you can always recover it as soon as you safely remove the malware from the system.


Name Cosacos
Type Ransomware
Danger Level High (Ransomware is by far the worst threat you can encounter)
Symptoms Very few and unnoticeable ones before the ransom notification comes up.
Distribution Method From fake ads and fake system requests to spam emails and contagious web pages.
Data Recovery Tool Currently Unavailable
Detection Tool

Cosacos Ransomware Removal


Some of the steps will likely require you to exit the page. Bookmark it for later reference.

Reboot in Safe Mode (use this guide if you don’t know how to do it).



We get asked this a lot, so we are putting it here: Removing parasite manually may take hours and damage your system in the process. We recommend downloading SpyHunter to see if it can detect parasite files for you.

Press CTRL + SHIFT + ESC at the same time and go to the Processes Tab. Try to determine which processes are dangerous. 


Right click on each of them and select Open File Location. Then scan the files with our free online virus scanner:

Drag and Drop Files Here to Scan
Maximum file size: 128MB.

This scanner is free and will always remain free for our website's users. You can find its full-page version at: https://howtoremove.guide/online-virus-scanner/

Scan Results

Virus Scanner Result

After you open their folder, end the processes that are infected, then delete their folders. 

Note: If you are sure something is part of the infection – delete it, even if the scanner doesn’t flag it. No anti-virus program can detect all infections.


Hold the Start Key and R –  copy + paste the following and click OK:

notepad %windir%/system32/Drivers/etc/hosts

A new file will open. If you are hacked, there will be a bunch of other IPs connected to you at the bottom. Look at the image below:

hosts_opt (1)

If there are suspicious IPs below “Localhost” – write to us in the comments.

Type msconfig in the search field and hit enter. A window will pop-up:


Go in Startup —> Uncheck entries that have “Unknown” as Manufacturer.

  • Please note that ransomware may even include a fake Manufacturer name to its process. Make sure you check out every process here is legitimate.


To remove parasite on your own, you may have to meddle with system files and registries. If you were to do this, you need to be extremely careful, because you may damage your system.

If you want to avoid the risk, we recommend downloading SpyHunter
a professional malware removal tool.

More information on SpyHunter, steps to uninstallEULAThreat Assessment Criteria, and Privacy Policy.

Type Regedit in the windows search field and press EnterOnce inside, press CTRL and F together and type the virus’s Name. 

Search for the ransomware  in your registries and delete the entries. Be extremely careful –  you can damage your system if you delete entries not related to the ransomware.

Type each of the following in the Windows Search Field:

  1. %AppData%
  2. %LocalAppData%
  3. %ProgramData%
  4. %WinDir%
  5. %Temp%

Delete everything in Temp. The rest just check out for anything recently added. Remember to leave us a comment if you run into any trouble!


How to Decrypt Cosacos files

We have a comprehensive (and daily updated) guide on how to decrypt your files. Check it out here.

If the guide doesn’t help, download the anti-virus program we recommended or try our free online virus scanner. Also, you can always ask us in the comments for help!

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