How to avoid loss of files caused by Coot ransomware

Also Known As: Coot virus
Distribution: Moderate
Damage level: Severe

Coot ransomware removal instructions

What is Coot?

Coot is one of many malicious programs that belong to the Djvu ransomware family. Ransomware is a form of software that blocks access to data by encryption. Victims who have files encrypted by ransomware cannot regain access unless they decode them with a decryption tool and/or key. To obtain these tools/keys, victims are encouraged to pay a ransom to cyber criminals. Instructions about how to decrypt files encrypted by Coot can be found in a text file named "_readme.txt". Coot places this file in folders that contain locked files. Furthermore, this ransomware renames each encrypted file by adding the ".coot" extension to the filename. For example, "1.jpg" becomes "1.jpg.coot".

The ransom message states that Coot encrypts files with the strongest encryption algorithm and the only way to decrypt them is to purchase a decryption tool and unique key. This can be done by contacting Coot's developers via the or email address and providing a personal ID. It is mentioned that the cost of decryption depends on how quickly victims contact the cyber criminals who designed this ransomware. The normal cost of the decryption tool and key is $980, however, if contacted within 72 hours of encryption, this cost is reduced to $490 (a 50% discount). Victims are permitted to send Coot's developers one encrypted file, which they will decrypt free of charge. They offer free decryption as 'proof' that they can provide tools that can decrypt the remaining files. Despite this, ransomware developers should never be trusted: they often do not keep their promises and send no decryption tools/keys, even when victims meet all demands/pay ransoms. Unfortunately, there are no other tools that capable of restoring files encrypted by Coot (only the developers have the keys/tools). Typically, the only way to recover files without having to pay a ransom is to restore them from a backup. Even if ransomware is removed from the system, all files remain encrypted (removing ransomware simply prevents any further encryption).

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

Coot decrypt instructions

Coot is just one of many ransomware-type programs. Further examples include One, .FC, and Elder. Most prevent victims from accessing their files so that they are tempted to pay cyber criminals ransoms (typically, via a cryptocurrency) for decryption software and/or keys. Common variables are cost of decryption and encryption algorithm (symmetric or asymmetric) used to encrypt data. In most cases, it is impossible to decrypt files without using tools held only by developers of specific ransomware, unless the ransomware it is not finished, contains bugs, flaws, etc. To avoid damage (data loss) caused by ransomware in future, have your data backed up and store it on unplugged storage devices or remote servers.

How did ransomware infect my computer?

Typically, malicious programs such as ransomware are distributed through spam campaigns, Trojans (other malicious programs), dubious file and software download tools/channels, fake software updating, and unofficial activation tools. One of the most common ways malware is spread is via emails that are sent containing malicious file attachments. For example, Microsoft Office or PDF documents, JavaScript files, executables (.exe), RAR, ZIP, and other files. If opened, these cause installation of malicious software. Trojans are malicious programs that, if already installed, cause chain infections. They are often designed proliferate malware. Untrustworthy software download channels/sources such as unofficial web pages, freeware download websites, free file hosting sites, third party downloaders, and Peer-to-Peer networks (eMule, torrent clients, etc.) often contain malicious files that are disguised as legitimate. Cyber criminals use them to trick people into downloading infected files. If opened, the files infect systems with high-risk malware. Fake software updaters usually exploit bugs/flaws of outdated software or simply install malicious programs rather than updates or fixes. Software 'cracking' tools are programs that supposedly bypass paid activation of software (i.e., they activate licensed software free of charge), however, they are commonly used to proliferate malicious programs.

Threat Summary:
Name Coot virus
Threat Type Ransomware, Crypto Virus, Files locker.
Detection Names AVG (FileRepMalware), BitDefender (Trojan.GenericKD.41955490), ESET-NOD32 (A Variant Of Win32/Injector.EION), Kaspersky (Trojan.Win32.Chapak.ebjm), Full List (VirusTotal)
Encrypted Files Extension .coot
Ransom Demanding Message _readme.txt
Ransom Amount $980/$490
Cyber Criminal Contact,
Symptoms Cannot open files stored on your computer, previously functional files now have a different extension (for example, my.docx.locked). A ransom demand message is displayed on your desktop. Cyber criminals demand payment of a ransom (usually in bitcoins) to unlock your files.
Additional Information This malware is designed to show a fake Windows Update window and modify the Windows "hosts" file to prevent users from accessing cyber security websites (more information below).
Distribution methods Infected email attachments (macros), torrent websites, malicious ads, unofficial activation and updating tools.
Damage All files are encrypted and cannot be opened without paying a ransom. Additional password-stealing trojans and malware infections can be installed together with a ransomware infection.

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How to protect yourself from ransomware infections

Emails with attached files sent from from unknown, suspicious addresses should not be trusted. Malicious emails are usually disguised as important and official, however, they are generally irrelevant to recipients. Do not download or install software using third party downloaders, installers, unofficial web pages or tools, Peer-to-Peer networks, or other tools mentioned above. Download from official, trustworthy websites and using direct download links. Update installed programs regularly, however, this should be achieved using tools or functions that are designed by official developers. Third party updaters cannot be trusted. Software 'cracking' tools are illegal and often cause installation of malware. If software is not free, it should be activated by formal purchase. Scan systems with reputable antivirus or anti-spyware software regularly. Keep this software up-to-date and remove detected threats immediately. If your computer is already infected with Coot, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Text presented in Coot ransomware text file ("_readme.txt"):


Don't worry, 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:
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" or "Junk" folder if you don't get answer more than 6 hours.

To get this software you need write on our e-mail:

Reserve e-mail address to contact us:

Your personal ID:

Screenshot of files encrypted by Coot (".coot" extension):

Files encrypted by Coot

Screenshot of fake Windows update pop-up displayed during the encryption:

Fake Windows pop-up displayed by Coot during the encryption

IMPORTANT NOTE! - As well as encrypting data, ransomware-type infections from the Djvu malware family also add a number of entries to the Windows "hosts" file. The entries contain URLs of various websites, most of which are related to malware removal. This is done to prevent users from accessing malware security websites and seeking help. Our website ( is also on the list. Removing these entries, however, is simple - you can find detailed instructions in this article (note that, although the steps are shown in the Windows 10 environment, the process is virtually identical on all versions of the Microsoft Windows operating system).

Screenshot of websites added to the Windows hosts file:

Tro Ransomware adding websites to Windows Hosts file

There are currently two versions of Djvu ransomware infections: old and new. The old versions were designed to encrypt data by using a hard-coded "offline key" whenever the infected machine had no internet connection or the server was timing out/not responding. Therefore, some victims were able to decrypt data using a tool developed by cyber security researcher, Michael Gillespie, however, since the encryption mechanism has been slightly changed (hence the new version, released in August, 2019), the decrypter no longer works and it is now not supported. If your data has been encrypted by an older version, you might be able to restore it with the another tool developed by Emsisoft and Michael Gillespie. It supports a total of 148 Djvu variants and you can find more information, as well as download link and decryption instructions, on the Emsisoft official web page.

Screenshot of Djvu decryption tool by Emsisoft and Michael Gillespie:

Djvu ransomware decrypter by Michael Gillespie and Emsisoft

Additionally, Emsisoft is now providing a service that allows data decryption (again, only if it was encrypted by Djvu variants released before August, 2019) for those victims who have copies of the file before and after encryption. Victims simply upload the original and encrypted file to Emsisoft's Djvu decryption web page and download the aforementioned decryption tool (the download link will be provided after uploading files). Note that file processing may take some time, so be patient. Note that the system must have a reliable internet connection during the entire decryption process, otherwise it will fail.

Screenshot of Emsisoft's Djvu decryption service web page:

Djvu ransomware decryption service by Emsisoft

Coot ransomware removal:

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Spyhunter is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
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Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the Coot virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the Coot ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining Coot ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of Coot are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by Coot, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as Coot ransomware.

Note that Windows 10 Fall Creators Update includes a "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default, this feature automatically protects files stored in the Documents, Pictures, Videos, Music, Favorites, and Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here is more information on how to get this update and add an additional protection layer from ransomware infections.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove Coot ransomware:

About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

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Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

QR Code
Coot virus QR code
A QR code (Quick Response Code) is a machine-readable code which stores URLs and other information. This code can be read using a camera on a smartphone or a tablet. Scan this QR code to have an easy access removal guide of Coot virus on your mobile device.
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