Home / Removal Guide / Ransomware / Djvu Virus / Cosakos Virus Removal Guide (+Decrypt .cosakos files) – DJVU Ransomware

Cosakos Virus Removal Guide (+Decrypt .cosakos files) – DJVU Ransomware

Cosakos Virus Ransomware

The Cosakos stands for a ransomware-type infection. Initially, it was revealed by Michael Gillespie. The virus comes from the DJVU ransomware family. Cosakos was elaborated specifically to encrypt all major file types. Once the file is encrypted people are not able to use them. Cosakos adds the “.cosakos” extension for each file encrypted by it. For example, the file “myphoto.jpg“, as soon as encrypted by Cosakos, will be renamed into “myphoto.jpg.cosakos. As soon as the encryption is finished, Cosakos places a special text file (such as “_readme.txt“) into every folder containing the encrypted data.

The message given by Cosakos text file requesting for the ransom is absolutely the same as the statements given by other ransomware representatives belonging to the DJVU clan. It literally discusses that the information is encrypted which the only way to restore it is to use a an unique decryption key. Sadly, this is definitely true. The sort of cryptography mechanism applied by Cosakos is still not properly examined. Still, it is definitely certain that each victim may be given the specific decryption key, which is totally unique. It is difficult to restore the files without the key available.

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

message from Cosakos virus

Another technique of Cosakos is that the victims cannot access to the key. The key is stored on a particular server run by the frauds associated with Cosakos ransomware. To get the key and recover the important information people need to pay the ransom, which amounts to $980. To obtain the payment information users are advised to contact the frauds through email or telegram. The alert likewise suggests that the users require to contact the Cosakos developers within 72 hours after the encryption occurred. The message says that doing so users will get a 50% discount, so the ransom quantity will fall to $490.

However, regardless of the requested amount, people need to keep away from paying the ransom virus. Cyber frauds are not fair, so they tend to totally ignore what their victims feel about the problem, even when the payment reaches their pockets. This is why paying the ransom normally does not provide any positive outcome and people simply lose their money for nothing.

We strongly encourage that you do not contact these crooks and absolutely do not transfer money into their accounts. It is said to admit that there are no utilities able to crack Cosakos ransomware and to recover the information data free of charge. Therefore, the only best decision is to recover the lost information from the available backup.

Virus Summary

Name Cosakos Ransomware
File Extension cosakos
Type Ransomware
Family DJVU
Short Description The 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.
Symptoms File encryption by the ransomware is performed by means of the RSA-1024 encryption algorithm. Once the encryption is completed, the ransomware adds its special cosakos extension to all the files modified by it.
Distribution Method Adware bundles and software cracks
Similar Infections Nvetud, Mogranos, Nelasod
Removal Tool   GridinSoft Anti-Malware

Bear in mind that the world wide web is now overwhelmed with threats that look comparable to Cosakos ransomware. It is similar Nvetud and many other ransomware-type threats. Destructive programs of such kind are typically elaborated to encrypt important data and to state the need prior to the user to pay the ransom. The peculiarity of all such ransomware threats is that all apply a similar algorithm to produce the distinct decryption key for data decryption.

Thus, as long as the ransomware is still being developed or has some hidden bugs, manually recovering the information is merely not feasible. The only way to prevent the loss of your important information is to routinely create backups of your important information.

Bear in mind that even if you create such backups, they must be put into a special storage utility not connect to your main PC. You may use the USB Memory Stick or external hard disk drive for this purpose, or refer to the help of the cloud storage. If you store your backup files on your common system they may be encrypted along with other files, so it’s absolutely not a good storage place.

How did ransomware infect my system?

There are a number of methods used by online frauds to distribute Cosakos ransomware. Despite the fact that it is uncertain how precisely Cosakos injects your PC, there are some leaks through which it may penetrate the system:

  • integration with third-party software, especially freeware;
  • spam emails from unidentified senders;
  • sites rendering free hosting services;
  • pirated peer-to-peer (P2P) downloads.

Typically Cosakos ransomware may be presented as some genuine software, for example, in the pop-ups instructing users to carry out some crucial software updates. This is the typical trick used by online scams to persuade people into downloading and installing Cosakos infection manually, by ways of their direct participation in the installation process.

Furthermore, the criminals may describe various email spam techniques to inject harmful codes into systems. So, they may refer to to sending unsolicited spam emails with tricky notices promoting users to download the attachments or click on certain download links, for example, the ones encouraging users to open some video, documents, tax reports or invoices.

Needless to mention, opening such documents or clicking on such dangerous links may significantly harm the PC. Fictitious Adobe Flash Player update notifies may result in Cosakos ransom injection. When it comes to the cracked software, these illegally downloaded programs may also consist of destructive codes resulting in Cosakos secret installation. Lastly, injection of Cosakos may occur by methods of Trojans that covertly get injected into the system and install malicious utilities without the user’s consent.

Is there any method to avoid the injection of Cosakos ransomware?

Despite the fact that there is no 100% guarantee to prevent your PC from getting infected, there are some pieces of guidance we want to share with with you. First of all, be really mindful when you browse the web and particularly while downloading complimentary programs. Stay away from opening suspicious email attachments, especially when the sender of the email is not familiar to you.

Bear in mind that some freeware installers may consist of other unwanted utilities in the bundle, so they may be harmful. Make sure that your current antivirus software and your entire OS is always appropriately updated.

Of course, downloading pirated software is unlawful and may result in necessary damage to be produced your system. Thus, stay away from downloading cracked software. You are also highly encouraged to reconsider your existing security software and potentially switch to another security solution that can render better services of protecting your computer.

Below please find the quotation from the Cosakos text file:

ATTENTION!
 
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:
https://we.tl/t-hvv30uAtTY
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:
gorentos@bitmessage.ch
 
Reserve e-mail address to contact us:
ferast@firemail.cc
 
Our Telegram account:
@datarestore

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

Cosakos Ransomware - encrypt files with .cosakos extension

Use GridinSoft Anti-Malware to remove Cosakos 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

[Total: 0    Average: 0/5]
Sending
User Review
0 (0 votes)
Comments Rating 0 (0 reviews)

About 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.

Check Also

How to uninstall Xtron PC Speedup

Xtron PC Speedup is a security app from rogue software family. When installed on the …

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.