Djvu VirusRansomwareRemoval Guide

Coos Virus Removal Guide (+Decrypt .coos files)

Coos Virus Ransomware

Coos is a harmful software application functioning as typical ransomware. Michael Gillespie, the widely known virus researcher, very first found this new name in the DJVU ransomware family.

Coos was created for the sole function to encrypt all popular file types. Rationally, as soon as the file encryption is effectively accomplished, the users are not able to get access to them. Coos ransomware adds its own “.coos” to all the encrypted files. For example, the file “price_list.xls”, as soon as modified by Coos, will be entitled as “price_list.xls.coos”. When the encryption is achieved, Coos puts its own unique text document (_readme.txt) into all the folders that store the encrypted files.

The alert specified by document asking for the random os very similar to the alerts given by other ransomware risks coming from the DJVU family. The caution essentially shows that the files have been encrypted and the only service to get access to it is to use a distinct standalone key. Regretfully, this declaration is absolutely real.

The approach to encrypt the files utilized by Coos is not entirely researched. However, there is no doubt that each computer system owner may be issued an unique decryption key, which is absolutely special. It is incredibly hard to recuperate the data without the suitable type in place.

“Don’t worry, you can return all your files!”, from text file message:

Don't worry, you can return all your files! virus

One more peculiarity of the Coos ransomware is that the users are unable to get access to the key. The decrypting key is hosted on an unique server under the complete control by the scoundrels who have actually released the Coos virus into the web. In order to obtain the key and bring back the important data, the users are told to connect with the frauds through e-mail or by telegram and to pay the ransom in the quantity of $980.

The message likewise says that the people must contact the Coos authors within 72 hours upon the minute of the data encryption. The alert indicates that by doing so individuals will acquire a 50% discount, for that reason, the ransom quantity falls to $490.

No matter what the quantity of the ransom is, we highly advise that you do not pay the ransom. There is no warranty that these online criminals will keep their promises, so they might not care at all what the victims feel about the file encryption, even when the amount of the ransom is received into their accounts. Hence, paying ransom frequently does not lead to a successful recovery. So, the users may simply lose their money for absolutely nothing.

Similarly, we advise you not to get in touch with the frauds as they instruct. Do not move loan into their wallets. There are no applications that might split the Coos virus or restore the information for free. For that reason, the only right decision is to bring back the data from possible backups (if readily available).

Virus Summary

NameCoos Ransomware
File Extensioncoos
Short DescriptionThe ransomware encrypts all the data stored on your system and requires a ransom to be paid on your part supposedly to recover your important files.
SymptomsFile encryption by the ransomware is performed by means of the AES-256 algorithm (CFB mode) encryption algorithm. Once the encryption is completed, the ransomware adds its special .coos extension to all the files modified by it.
Distribution MethodAdware bundles and software cracks
Similar InfectionsQlkm, Atek, Igal
Coos Removal Tool   GridinSoft Anti-Malware
Coos Decryption Tool   Emsisoft Djvu Decryptor

Do not forget that the Internet is now filled with infections comparable to the Coos virus. For example, this specific danger is basically similar to Brusaf and other ransomware-type infections. These harmful utilities have been established in order to secure the essential information and reveal the demand for the users to pay the ransom. All these infections utilize the similar algorithm to create the specific key for effective information decryption.

Unless the Coos ransomware is still under the advancement procedure or has actually got some hidden bugs, it is not possible to restore the data manually. Therefore, the only working option to prevent the loss of your important data is to frequently preserve updated backups of all your important files.

Another important piece of advice is to store the backups on unique storage not linked to your main PC. For instance, you might save it on the USB Flash Drive, or some external disk drive, or by using the cloud data storage services. Keeping the backups on your regular drive is very risky, because the backup might also be secured by the Coos infection.

Leakages for the Coos ransomware attack.

Coos uses lots of paths to penetrate the susceptible computer systems. It is not certain what particular approach was used in your case, however, the intrusion may happen by means of the following channels:

  • bundling with third-party programs, primarily free software;
  • spam emails from the unidentified senders;
  • sites providing free hosting;
  • P2P (peer-to-peer) torrent downloads.

There are times when the Coos virus may camouflage itself as some authentic application, for instance, through the deceptive notifies requiring installation of some software application update. This is the most common technique utilized by the frauds to inject the Coos virus files into the system. This way users partially take part in its setup, without plainly comprehending the threat.

Additionally, the frauds may send unsolicited spam email with difficult signals motivating the people to open suspicious accessories or click some download links, for example, those encouraging individuals to open specific images, text files, tax files and other info.

No doubt, opening these files or clicking on the malicious links may essentially harm the system. Fake Media Player upgrade notices may result in the Coos ransomware infiltration. Similarly, downloading the split software might furthermore consist of the ransomware installer. The last but not the least, installation of Coos might occur through some Trojan horses that may be installed stealthily into the system and without the user’s direct permission or perhaps approval.

Preventing the Coos virus attack.

Naturally, there is no outright assurance that your computer will be always free of any malware attacks, nevertheless, we want to share some helpful ideas with you to make it safer. Make certain to pay really attention while browsing the web and specifically while downloading cost-free programs. Do not open any suspicious e-mail accessories, especially if the sender is not understood to you.

Do not forget that particular freeware installer might likewise consist of some other additional apps in the bundle. These additional applications might be very destructive. It is of utmost value to keep your anti-virus software application and your operating system in general to be constantly properly updated.

It is rather rational that downloading cracked apps is illegal, however, furthermore, such unapproved apps use may likewise bring severe damage to your system. For this reason, do not download any cracked programs. Plus, the truth that your current anti-virus did not protect the system from the Coos ransomware is a great factor for you to reevaluate your options and change to another program that can render the safeguarding functions on a better level.

Below please find the quotation from the Coos text file:

 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: 

 Our Telegram account:

Screenshot of files with “.coos” extension added by the ransomware:”

Coos Ransomware - encrypt files with .coos extension

Use GridinSoft Anti-Malware to remove Coos ransomware from your computer

1.Download GridinSoft Anti-Malware.

You can download GridinSoft Anti-Malware by clicking the button below:

  GridinSoft Anti-Malware

2. Double-click on the setup file.

When setup file has finished downloading, double-click on the setup-antimalware-ag.exe file to install GridinSoft Anti-Malware on your computer.
GridinSoft Anti-Malware
An User Account Control asking you about to allow GridinSoft Anti-Malware to make changes to your device. So, you should click “Yes” to continue with the installation.
GridinSoft Anti-Malware Setup

3. Press Install button for run GridinSoft Anti-Malware.

GridinSoft Anti-Malware Install

3.Once installed, GridinSoft Anti-Malware will automatically run.

GridinSoft Anti-Malware  Start

4. Wait for the GridinSoft Anti-Malware scan to complete.

GridinSoft Anti-Malware will automatically start scanning your computer for Win Speedup 2018 and other malicious programs. This process can take a 20-30 minutes, so we suggest you periodically check on the status of the scan process.
GridinSoft Anti-Malware Scan

5. Click on “Clean Now”.

When the scan has completed, you will see the list of infections that GridinSoft Anti-Malware has detected. To remove them click on the “Clean Now” button in right corner.
GridinSoft Anti-Malware Scan Result

Use Emsisoft Decryptor for restore coos files

You can get Emsisoft Decryptor by clicking the button below:

  Emsisoft Decryptor

  1. Run the decryptor as an administrator. The license terms will show up, which you have to agree to by clicking the “Yes” button.
  2. Once the license terms are accepted, the primary decryptor user interface opens.
  3. By default, the decryptor will pre-populate the locations to decrypt with the currently connected drives and network drives. Additional locations can be added using the Add” button.
  4. Decryptors typically offer various options depending on the particular malware family. The available options are located in the Options tab and can be enabled or disabled there. You can find a detailed list of the available Options below.
  5. After you have added all the locations you want to decrypt to the list, click the “Decrypt” button to start the decryption process. The screen will switch to a status view, informing you about the current process and decryption status of your files
  6. The decryptor will inform you once the decryption process is finished. If you require the report for your personal records, you can save it by clicking the “Save log” button. You can also copy it straight to your clipboard to paste it into emails or forum posts if you are asked to.
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Daniel Zimmermann

Daniel Zimmermann has been writing on security and malware subjects for many years and has been working in the security industry for over 10 years. Daniel was educated at the Saarland University in Saarbrücken, Germany and currently lives in New York.

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