Cosd Virus


Cosd is a Ransomware infection that abuses its victims by taking hostage of files that are of great value to them. In return for providing means to liberate the target files, Cosd demands a ransom payment and displays a money-requesting notification on the infected computers’ screen.


The Cosd virus ransom note

Ransomware is a popular type of malware that is used to abuse web users through blackmail. A major problem with such threats is that it is easy for the malware to sneak unnoticed inside the device and encrypt all the data that is stored there without being detected. This is because most Ransomware infections, including Cosd, .Plam, .Pola will typically not trigger any visible symptoms of their presence during the attack. Moreover, the method used to keep the user information inaccessible is known as data encryption, and once the information is encrypted by the malware, it becomes virtually impossible to access it without applying a uniquely generated decryption key.

The hackers behind Cosd focus on offering the victims to purchase that decryption key from them for a fixed amount of money. They typically display a ransom notification on the screen of the infected machines with instructions about how to transfer the required money in order to obtain the corresponding key for their files.

Many individuals who can’t afford to lose access to important data give in to the blackmail scheme and send the ransom money to the crooks. But, sadly, not all users who make the ransom payment manage to regain access to their encrypted files. There are many instances where the people get nothing in return for their money and are left with inaccessible bits of data and empty pockets. This is yet another critical thing when it comes to facing Ransomware infections like Cosd – there is never an assurance that you will access your data again, even after you fulfill the demands of the hackers behind the infection.

The Cosd virus

The Cosd virus is a piece of malware that can cause significant data loss by restricting user access to it. The Cosd virus normally encrypts files that are most frequently used and displays a notice on the screen, where a ransom payment is required to regain access to them.

cosd virus

The Cosd virus encrypted files

Users who do not want to put their hard-earned money at risk by giving it to the offenders,  however, are advised to explore other options to deal with the encryption and remove Cosd.

Of course, we need to note that none of the alternatives can give guarantees as to how the data will be retrieved and how many files will become accessible again. Still, doing some extensive research and choosing legitimate ransomware recovery options (such as those listed in the file-recovery section below) is much more advisable than transferring money to anonymous hackers and hoping that one day they will send you a special decryption key.

The Cosd file recovery

The Cosd file recovery is a way for the users to regain access to their encrypted information. Fortunately, there are some free methods for Cosd file recovery such as using a personal backup or shadow copy restore process.

There are other solutions online, and while they might not all work, most of them may still be worth the try, especially if you don’t have to contact hackers or transfer money to them. However, in order to have better chances to recover anything, make sure you first remove Cosd with the instructions in the guide that follows.


Name Cosd
Type Ransomware
Detection Tool

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Remove Cosd Ransomware


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).



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:

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    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.


    Type Regedit in the windows search field and press Enter. Once 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 Cosd 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!


    About the author


    Lidia Howler

    Lidia is a web content creator with years of experience in the cyber-security sector. She helps readers with articles on malware removal and online security. Her strive for simplicity and well-researched information provides users with easy-to-follow It-related tips and step-by-step tutorials.

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