Cadq Ransomware - How to remove

Cadq is a malicious program. It breaks files so that they can’t be opened and renames them to enc with “.cadq”. It also leaves behind a ransom note asking for hundreds of dollars in exchange for fixing the files.

Cadq ransomware causes harm that might be unfixable in some cases. First of all, it needs to be removed from your computer.

About Cadq in short:

Threat type Ransomware,


How to recognize Cadq It changes the names of your files,

it corrupts files, making them impossible to read.

Can you get your files back Restore data from backups,

use file recovery tools,

see if file decryption might be possible.

How to remove Cadq Remove ransomware and other malware with antivirus programs (Spyhunter, others),

repair your hosts file.

How Cadq ransomware works

Cadq is malicious software that encrypts the files on the computer that it infects. Encryption is widely (and legitimately) used to encode information so that those who don’t have the password (or the decryption key) can’t read it. When Cadq does it to your files, it basically corrupts them.

You might recognize Cadq by how it changes the names of the files that it encrypts. It adds “.cadq” as a second extension.


This extension is just a label. Removing it does not fix the files.

It’s worth noting that Cadq sometimes only encrypts data partially, in which cases, the files might still partially work – for example, audio tracks might still play and only lose a few seconds here and there.

Cadq is new ransomware, but we know a lot about it because it’s part of Djvu – a well-known family of file-encrypting malware. Cadq was recently preceded by Ygkz, Pola, and other Djvu variants.

Cadq's ransom note asks for a payment.

Can you repair your files?

There’s no easy way to repair the files that Cadq encrypted. It deletes backups stored on the PC. So, if you have backups of your data (on an external drive, in the cloud, etc.), then restoring them would be the best.

It’s also possible that Cadq skipped some of your files, so check your folders carefully.

If you don’t have backups, then you can look into a few other ways in which it’s possible to maybe restore some of the data that Cadq broke (I don’t want to give you false hope for bringing back your files):

  • Try the Emsisoft decryptor. In very limited circumstances, there’s a possibility that you might be able to get your files decrypted.
  • Scan your device with a file recovery program (for instance, EaseUS). Recovery programs usually allow a free scan – maybe some valuable data can still be restored.
  • For some file types, repair might be possible.

Cadq’s ransom note asks victims to pay from $490 to $980 for a decryptor. It’s not recommended to pay the ransom. The cybercriminals behind this attack are not guaranteed to help you. In the past, quite a few Djvu victims reported getting scammed (they sent the money but never received working decryption tools). Technical problems are likely, too (the decryption key doesn’t work).

How to remove Cadq

Separately from restoring the data that Cadq encrypted, Cadq and other malware need to be deleted. Below are the instructions for starting your PC in safe mode, which can help you remove threats more effectively.

If you don’t want to wipe your PC as some ransomware victims choose to do, then you can use an antivirus scanner (like Spyhunter) to catch all the malware. It’s likely that other malware besides the ransomware is present.

Cadq spreads embedded in pirated files and modified distributions of legitimate programs. And it might be bundled with other malicious infections (such as Azorult) which also must be deleted as quickly as possible.

Since the malware tries to disable antivirus programs and delete files important to them, it might be good to reinstall them or validate the installations. And since Cadq blocks some websites, we added the instructions for manually fixing your hosts file.

And once you’ve removed all the threats, it’s recommended to reset your passwords and make sure that you’re using 2-factor authentication where possible. This’ll protect your online accounts from being hacked in case spyware read your credentials.

Important -- edit the hosts file to unblock security websites

TL DR : The hosts file is edited to block security sites Before the virus can be removed, it's necessary to fix the hosts file (the file which controls which addresses connect to which IPs). That is the reason the majority of security websites is inaccessible when infected with this particular parasite. This infection edits this file to stop certain websites, including anti-malware download sites, from being accessed from the infected computer, making browsers return the "This site can't be reached" error. Luckily, it's trivial to fix the file and remove the edits that were made to it.

Find and edit the hosts file

The hosts file can be found on C:/Windows/System32/Drivers/etc/hosts. If you don't see it, change the settings to see hidden files.
  1. In the Start Menu, search for Control Panel.
  2. In the Control Panel, find Appearance and Personalization.
  3. Select Folder Options.
  4. Open the View tab.
  5. Open Advanced settings.
  6. Select "Show hidden files...".
  7. Select OK.
Open this file with administrator privileges. notepad run as administrator
  1. Open the Start Menu and enter "notepad".
  2. When Notepad shows up in the result, right-click on it.
  3. In the menu, choose "Run as administrator"
  4. File->Open and browse for the hosts file.
The hosts file should look like this: hosts file default contents Delete additional lines that they connect various domain names to the wrong IP address. Save the file.

Download and run the antivirus program

After that, download antivirus programs and use them to remove the ransomware, the trojan, and other malware. Spyhunter (

Automatic Malware removal tools

Download Spyhunter for Malware detection

Note: Spyhunter trial provides detection of parasites and assists in their removal for free. limited trial available, Terms of use, Privacy Policy, Uninstall Instructions,

Download Combo Cleaner for Malware detection

Note: Combo Cleaner trial provides detection of parasites and assists in their removal for free. limited trial available, Terms of use, Privacy Policy, Uninstall Instructions, Refund Policy ,

How to recover Cadq Ransomware encrypted files and remove the virus

Step 1. Restore system into last known good state using system restore

1. Reboot your computer to Safe Mode with Command Prompt:

for Windows 7 / Vista/ XP
  • Start Shutdown RestartOK.
  • Press F8 key repeatedly until Advanced Boot Options window appears.
  • Choose Safe Mode with Command Prompt. Windows 7 enter safe mode

for Windows 8 / 10
  • Press Power at Windows login screen. Then press and hold Shift key and click Restart. Windows 8-10 restart to safe mode
  • Choose TroubleshootAdvanced OptionsStartup Settings and click Restart.
  • When it loads, select Enable Safe Mode with Command Prompt from the list of Startup Settings. Windows 8-10 enter safe mode

2.Restore System files and settings.

  • When Command Prompt mode loads, enter cd restore and press Enter.
  • Then enter rstrui.exe and press Enter again.CMD commands
  • Click “Next” in the windows that appeared. Restore point img1
  • Select one of the Restore Points that are available before Cadq Ransomware has infiltrated to your system and then click “Next”. Restore point img2
  • To start System restore click “Yes”. Restore point img3

Step 2. Complete removal of Cadq Ransomware

After restoring your system, it is recommended to scan your computer with an anti-malware program, like Spyhunter and remove all malicious files related to Cadq Ransomware. You can check other tools here.  

Step 3. Restore Cadq Ransomware affected files using Shadow Volume Copies

If you do not use System Restore option on your operating system, there is a chance to use shadow copy snapshots. They store copies of your files that point of time when the system restore snapshot was created. Usually Cadq Ransomware tries to delete all possible Shadow Volume Copies, so this methods may not work on all computers. However, it may fail to do so. Shadow Volume Copies are only available with Windows XP Service Pack 2, Windows Vista, Windows 7, and Windows 8. There are two ways to retrieve your files via Shadow Volume Copy. You can do it using native Windows Previous Versions or via Shadow Explorer. a) Native Windows Previous Versions Right-click on an encrypted file and select PropertiesPrevious versions tab. Now you will see all available copies of that particular file and the time when it was stored in a Shadow Volume Copy. Choose the version of the file you want to retrieve and click Copy if you want to save it to some directory of your own, or Restore if you want to replace existing, encrypted file. If you want to see the content of file first, just click Open.
Previous version
b) Shadow Explorer It is a program that can be found online for free. You can download either a full or a portable version of Shadow Explorer. Open the program. On the left top corner select the drive where the file you are looking for is a stored. You will see all folders on that drive. To retrieve a whole folder, right-click on it and select “Export”. Then choose where you want it to be stored.
Shadow explorer

Step 4. Use Data Recovery programs to recover Cadq Ransomware encrypted files

There are several data recovery programs that might recover encrypted files as well. This does not work in all cases but you can try this:
  • We suggest using another PC and connect the infected hard drive as slave. It is still possible to do this on infected PC though.
  • Download a data recovery program.
  • Install and scan for recently deleted files. Data Recovery Pro
Note: In many cases it is impossible to restore data files affected by modern ransomware. Thus I recommend using decent cloud backup software as precaution. We recommend checking out Carbonite, BackBlaze, CrashPlan or Mozy Home.

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