Remove Cadq ransomware (Virus Removal Instructions) - Decryption Steps Included

removal by Jake Doevan - - | Type: Ransomware

Cadq virus Removal Guide

What is Cadq ransomware?

Cadq ransomware – a file-locking computer infection that demands a ransom in cryptocurrency

Cadq ransomwareCadq ransomware is a data-locking virus that encrypts all pictures, videos, documents, and other files on the system and then asks users to pay a ransom of $980/$490 for their return

Cadq ransomware is a cryptovirus created to encrypt non-system files on an infected computer and demands a ransom in Bitcoins for a decryption toolkit. It does that through a generated ransom note named _readme.txt, where criminal instructions and demands are presented. During the encryption, all personal data, such as documents, pictures, archives, etc., is renamed by appending a .cadq extension. For example, a file called “1.pdf” would be turned into “1.pdf.cadq.”

Like all Djvu family ransomware members, Cadq virus alters the system registry, files, and other core system settings to establish persistence. That makes its elimination troublesome but not impossible. If your machine got infected with this file-locker, you came to the right place to find out how that might have happened, how to evade such perils, and how to get rid of it.

The main goal of the threat actors behind the Cadq ransomware virus is to push their victims into contacting them via two given emails (helpteam@mail.ch and helpmanager@airmail.cc) and to make them pay the ransom ($490/$980). Fortunately, companies are dedicating their work to help ransomware victims. Please don't pay the criminals, as there might a way to recover your files without spending a dime.

name Cadq ransomware
Type File-locking virus
Family Djvu
Ransom note _readme.txt
Ransom amount The original ransom sum is $980. If victims contact criminals within 72 hours, a 50% discount is applied to lower the price to $490
Appended file extension .cadq
Distribution File-sharing platforms, software cracks
criminal contact details Assailants provide two emails to get in touch with them – helpteam@mail.ch and helpmanager@airmail.cc
Malware removal Trustworthy anti-malware tools should be used to safely eliminate this ransomware along with any other malware or junkware
System repair File-lockers alter system files, services, and settings, which could cause various system irregularities or even infection renewal. Use the powerful ReimageIntego system repair tool to fix all system inconsistencies

The ransom note of the Cadq virus doesn't differ much from other versions of Djvu family ransomware. It contains an appointed user ID, two contact email addresses, a statement that only the criminals can decrypt locked data, and techniques to convince victims to jump to rash decisions and forward Bitcoins to the assailants:

  • an offer to decipher one encrypted file for free,
  • a hyperlink to a video where the supposed decryptor can be seen in action,
  • a 50% discount on the ransom amount for victims that reach out to the threat actors within 72 hours of the attack.

The entire message, in the _readme.txt ransom note, reads:

ATTENTION!

Don't worry, you can return all your files!
All your files like pictures, 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:
hxxps://we.tl/t-Wl6WKEBetp
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:
helpteam@mail.ch

Reserve e-mail address to contact us:
helpmanager@airmail.cc

Your personal ID:

Djvu family file-lockers have been around for a while now, and it's still developing new infections each week. In fact, reports show,[1] that in the third quarter of 2020, almost 70% of all reported ransomware attacks were performed by cryptoviruses of this lineage. Here are some of the latest versions:

All variations have many similarities. Their ransom notes are practically identical. Contact emails almost never change. All recent versions use the RSA 2048 encryption algorithms,[2] and all of them alter system files and settings to establish persistence.

Cadq ransomware virusCadq ransomware is a virus that belongs to a well-known Djvu malware family

Due to their pervasiveness, some companies, like Emisoft, have dedicated themselves to helping ransomware attack victims by developing free decryption software. There's no guarantee that such a tool will work if your device is infected with Cadq file virus, but it won't hurt to try.

The only way to stop cybercriminals from spreading cryptoviruses is to stop paying ransoms. If the cash flow stops, the attacks will stop as well. Therefore, you should remove Cadq ransomware from your infected Windows devices. We suggest doing that with reliable anti-malware tools such as SpyHunter 5Combo Cleaner or Malwarebytes.

As we've mentioned before, file-lockers alter various system settings and files, which may result in BSoD, freezing, severe lag, or even infection renewal. That's why cybersecurity experts at LesVirus.fr[3] highly recommend using the ReimageIntego system diagnostics tool after Cadq ransomware removal.

Djvu family ransomware are infecting computers of file-sharing platform users

Cybercriminals are actively exploiting users who try to cheat the system by downloading copyrighted software for free from file-sharing platforms, particularly the most popular torrent sites. Most of these portals don't have end-to-end security, meaning no one is inspecting the uploaded content.

This is one of the main reasons why threat actors are using these platforms to spread their creations. The other one is that they can reach broad audiences around the world. And the last one – there's not much work to do. Mainly, hackers just need to think of a catchy name that would lure the soon-to-be victims to download the camouflaged infection.

Our cybersecurity team has reported that most ransomware was disguised either as game cracks or pirated commercial software. But that doesn't mean that other torrents can be harvesting malware too. So please think twice before downloading anything from such websites, as you can get yourself in heaps of trouble.

Remove Cadq ransomware properly with anti-malware tools and run system diagnostics

Having your device infected with ransomware is no joke, and the action should be taken immediately. First off, please don't even consider paying the developers of the Cadq virus as that's the most irresponsible thing to do. Ransom money would be used to infect more innocent people's computers and expand the hackers' illegal empire.

Cadq virusOnce Cadq virus encrypts files, recovering them without a decryption key is rather difficult

If you had a security tool, it clearly failed you by letting the cyber infection through. Get a trustworthy anti-malware tool that will be able to automatically remove Cadq ransomware from your device and protect it from such attacks in the future. We advise acquiring either SpyHunter 5Combo Cleaner or Malwarebytes.

But before you eliminate the cryptovirus, give free Emisoft decryptor a go. Maybe you'll be lucky, and it will unlock your files. If not, try our suggestions at the bottom of the page. There you'll also find instructions on how to launch your device in safe mode if the file-locker prevents you from opening a security tool.

And last but definitely not least, after Cadq ransomware removal, you have to run system diagnostics because this infection probably altered key system attributes, such as the registry, host files, and so on. All these modifications could result in various abnormal pc behavior, such as crashing, freezing, or even infection renewal. To fix all system-related issues and get your device to a pre-contamination phase with a push of a button, we highly recommend using the powerful ReimageIntego system tune-up tool.

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What to do if failed?
If you failed to remove virus damage using Reimage Intego, submit a question to our support team and provide as much details as possible.
Reimage Intego has a free limited scanner. Reimage Intego offers more through scan when you purchase its full version. When free scanner detects issues, you can fix them using free manual repairs or you can decide to purchase the full version in order to fix them automatically.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Reimage, try running SpyHunter 5.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Intego, try running Combo Cleaner.

Getting rid of Cadq virus. Follow these steps

Important steps to take before you begin Cadq removal

File encryption and ransomware infection are two independent processes (although the latter would not be possible without the former). However, it is important to understand that malware performs various changes within a Windows operating system, fundamentally changing the way it works.

IMPORTANT for those without backups! → 
If you attempt to use security or recovery software immediately, you might permanently damage your files, and even a working decryptor then would not be able to save them.

Before you proceed with the removal instructions below, you should copy the encrypted Cadq ransomware files onto a separate medium, such as USB flash drive or SSD, and then disconnect them from your computer. Encrypted data does not hold any malicious code, so it is safe to transfer to other devices.

The instructions below might initially seem overwhelming and complicated, but they are not difficult to understand as long as you follow each step in the appropriate order. This comprehensive free guide will help you to handle the malware removal and data recovery process correctly.

If you have any questions, comments, or are having troubles with following the instructions, please do not hesitate to contact us via the Ask Us section.

IMPORTANT! →
It is vital to eliminate malware infection from the computer fully before starting the data recovery process, otherwise ransomware might re-encrypt retrieved files from backups repeatedly.

Isolate the infected computer

Some ransomware strains aim to infect not only one computer but hijack the entire network. As soon as one of the machines is infected, malware can spread via network and encrypt files everywhere else, including Network Attached Storage (NAS) devices. If your computer is connected to a network, it is important to isolate it to prevent re-infection after ransomware removal is complete.

The easiest way to disconnect a PC from everything is simply to plug out the ethernet cable. However, in the corporate environment, this might be extremely difficult to do (also would take a long time). The method below will disconnect from all the networks, including local and the internet, isolating each of the machines involved.

  • Type in Control Panel in Windows search and press Enter
  • Go to Network and InternetNetwork and internet
  • Click Network and Sharing CenterNetwork and internet 2
  • On the left, pick Change adapter settingsNetwork and internet 3
  • Right-click on your connection (for example, Ethernet), and select DisableNetwork and internet 4
  • Confirm with Yes.

If you are using some type of cloud storage you are connected to, you should disconnect from it immediately. It is also advisable to disconnect all the external devices, such as USB flash sticks, external HDDs, etc. Once the malware elimination process is finished, you can connect your computers to the network and internet, as explained above, but by pressing Enable instead.

Scan your system with anti-malware to remove Cadq

If you are a victim of ransomware, you should employ anti-malware software for its removal. Some ransomware can self-destruct after the file encryption process is finished. Even in such cases, malware might leave various data-stealing modules or could operate in conjunction with other malicious programs on your device. 

SpyHunter 5Combo Cleaner can detect and eliminate all ransomware-related files, additional modules, along with other viruses that could be hiding on your system. The security software is really easy to use and does not require any prior IT knowledge to succeed in the Cadq ransomware removal process.

Repair damaged system components

Once a computer is infected with malware such as ransomware, its system is changed to operate differently. For example, an infection can alter the Windows registry database, damage vital bootup, and other sections, delete or corrupt DLL files, etc. Once a system file is damaged by malware, antivirus software is not capable of doing anything about it, leaving it just the way it is. Consequently, users might experience performance, stability, and usability issues, to the point where a full Windows reinstall is required.

Therefore, we highly recommend using a one-of-a-kind, patented technology of ReimageIntego repair. Not only can it fix virus damage after the infection, but it is also capable of removing malware that has already broken into the system thanks to several engines used by the program. Besides, the application is also capable of fixing various Windows-related issues that are not caused by malware infections, for example, Blue Screen errors, freezes, registry errors, damaged DLLs, etc.

  • Download the application by clicking on the link above
  • Click on the ReimageRepair.exe
    Reimage download
  • If User Account Control (UAC) shows up, select Yes
  • Press Install and wait till the program finishes the installation processReimage installation
  • The analysis of your machine with begin immediatelyReimage scan
  • Once complete, check the results – they will be listed in the Summary
  • You can now click on each of the issues and fix them manually
  • If you see many problems that you find difficult to fix, we recommend you purchase the license and fix them automatically.Reimage results

By employing ReimageIntego, you would not have to worry about future computer issues, as most of them could be fixed quickly by performing a full system scan at any time. Most importantly, you could avoid the tedious process of the Windrows reinstallation in case things go very wrong due to one reason or another.

Restore Windows "hosts" file to its original state

Some ransomware might modify Windows hosts file in order to prevent users from accessing certain websites online. For example, Djvu ransomware variants add dozens of entries containing URLs of security-related websites, such as 2-spyware.com. Each of the entries means that users will not be able to access the listed web addresses and will receive an error instead.

Here's an example of “hosts” file entries that were injected by ransomware:

Hosts file

In order to restore your ability to access all websites without restrictions, you should either delete the file (Windows will automatically recreate it) or remove all the malware-created entries. If you have never touched the “hosts” file before, you should simply delete it by marking it and pressing Shift + Del on your keyboard. For that, navigate to the following location:

C:\\Windows\\System32\\drivers\\etc\\

Delete Windows "hosts" file

Restore files using data recovery software

Since many users do not prepare proper data backups prior to being attacked by ransomware, they might often lose access to their files permanently. Paying criminals is also very risky, as they might not fulfill the promises and never send back the required decryption tool.

While this might sound terrible, not all is lost – data recovery software might be able to help you in some situations (it highly depends on the encryption algorithm used, whether ransomware managed to complete the programmed tasks, etc.). Since there are thousands of different ransomware strains, it is immediately impossible to tell whether third-party software will work for you.

Therefore, we suggest trying regardless of which ransomware attacked your computer. Before you begin, several pointers are important while dealing with this situation:

  • Since the encrypted data on your computer might permanently be damaged by security or data recovery software, you should first make backups of it – use a USB flash drive or another storage.
  • Only attempt to recover your files using this method after you perform a scan with anti-malware software.

Install data recovery software

  1. Download Data Recovery Pro.
  2. Double-click the installer to launch it.
    Launch installer
  3. Follow on-screen instructions to install the software.Install program
  4. As soon as you press Finish, you can use the app.
  5. Select Everything or pick individual folders where you want the files to be recovered from.Select what to recover
  6. Press Next.
  7. At the bottom, enable Deep scan and pick which Disks you want to be scanned.Select Deep scan
  8. Press Scan and wait till it is complete.Scan
  9. You can now pick which folders/files to recover – don't forget you also have the option to search by the file name!
  10. Press Recover to retrieve your files.Recover files

Use Emsisoft decrytor for Djvu/STOP

If you have infected your computer with one of the Djvu variants, you should try using Emsisoft decryptor for Djvu/STOP. It is important to mention that this tool will not work for everyone – it only works if data was locked with an offline ID due to malware failing to communicate with its remote servers.

Even if your case meets this condition, somebody from the victims has to pay criminals, retrieve an offline key, and then share it with security researchers at Emsisoft. As a result, you might not be able to restore the encrypted files immediately. Thus, if the decryptor says your data was locked with an offline ID but cannot be recovered currently, you should try later. You also need to upload a set of files – one encrypted and a healthy one to the company's servers before you proceed.

  • Download the app from the official Emsisoft website.Download Djvu/Stop decryptor from Emsisoft
  • After pressing Download button, a small pop-up at the bottom, titled decrypt_STOPDjvu.exe should show up – click it.
    Click on decrypt_STOPDjvu.exe
  • If User Account Control (UAC) message shows up, press Yes.
  • Agree to License Terms by pressing Yes.
    Agree to License Terms
  • After Disclaimer shows up, press OK.
  • The tool should automatically populate the affected folders, although you can also do it by pressing Add folder at the bottom.
    Add folders
  • Press Decrypt.
    Decrypt Djvu files

From here, there are three available outcomes:

  1. Decrypted!” will be shown under files that were decrypted successfully – they are now usable again.
  2. Error: Unable to decrypt file with ID:” means that the keys for this version of the virus have not yet been retrieved, so you should try later.
  3. This ID appears to be an online ID, decryption is impossible” – you are unable to decrypt .Cadq ransomware files with this tool.

Create data backups to avoid file loss in the future

One of the many countermeasures for home users against ransomware is data backups. Even if your Windows get corrupted, you can reinstall everything from scratch and retrieve files from backups with minimal losses overall. Most importantly, you would not have to pay cybercriminals and risk your money as well.

Therefore, if you have already dealt with a ransomware attack, we strongly advise you to prepare backups for future use. There are two options available to you:

  • Backup on a physical external drive, such as a USB flash drive or external HDD.
  • Use cloud storage services.

The first method is not that convenient, however, as backups need to constantly be updated manually – although it is very reliable. Therefore, we highly advise choosing cloud storage instead – it is easy to set up and efficient to sustain. The problem with it is that storage space is limited unless you want to pay for the subscription.

Using Microsoft OneDrive

OneDrive is a built-in tool that comes with every modern Windows version. By default, you get 5 GB of storage that you can use for free. You can increase that storage space, but for a price. Here's how to setup backups for OneDrive:

  1. Click on the OneDrive icon within your system tray.
  2. Select Help & Settings > Settings.
    Go to OneDrive settings
  3. If you don't see your email under the Account tab, you should click Add an account and proceed with the on-screen instructions to set yourself up.
    Add OneDrive account
  4. Once done, move to the Backup tab and click Manage backup.
    Manage backup
  5. Select Desktop, Documents, and Pictures, or a combination of whichever folders you want to backup.
  6. Press Start backup.
    Pick which folders to sync

After this, all the files that are imported into the above-mentioned folders will be automatically backed for you. If you want to add other folders or files, you have to do that manually. For that, open File Explorer by pressing Win + E on your keyboard, and then click on the OneDrive icon. You should drag and drop folders you want to backup (or you can use Copy/Paste as well).

Using Google Drive

Google Drive is another great solution for free backups. The good news is that you get as much as 15GB for free by choosing this storage. There are also paid versions available, with significantly more storage to choose from.

You can access Google Drive via the web browser or use a desktop app you can download on the official website. If you want your files to be synced automatically, you will have to download the app, however.

  1. Download the Google Drive app installer and click on it.
    Install Google Drive app
  2. Wait a few seconds for it to be installed.Complete installation
  3. Now click the arrow within your system tray – you should see Google Drive icon there, click it once.
    Google Drive Sign in
  4. Click Get Started.Backup and sync
  5. Enter all the required information – your email/phone, and password.Enter email/phone
  6. Now pick what you want to sync and backup. You can click on Choose Folder to add additional folders to the list.
  7. Once done, pick Next.Choose what to sync
  8. Now you can select to sync items to be visible on your computer.
  9. Finally, press Start and wait till the sync is complete. Your files are now being backed up.

Report the incident to your local authorities

Ransomware is a huge business that is highly illegal, and authorities are very involved in catching malware operators. To have increased chances of identifying the culprits, the agencies need information. Therefore, by reporting the crime, you could help with stopping the cybercriminal activities and catching the threat actors. Make sure you include all the possible details, including how did you notice the attack, when it happened, etc. Additionally, providing documents such as ransom notes, examples of encrypted files, or malware executables would also be beneficial.

Law enforcement agencies typically deal with online fraud and cybercrime, although it depends on where you live. Here is the list of local authority groups that handle incidents like ransomware attacks, sorted by country:

Internet Crime Complaint Center IC3

If your country is not listed above, you should contact the local police department or communications center.

Manual Cadq removal using Safe Mode

Important! →
Manual removal guide might be too complicated for regular computer users. It requires advanced IT knowledge to be performed correctly (if vital system files are removed or damaged, it might result in full Windows compromise), and it also might take hours to complete. Therefore, we highly advise using the automatic method provided above instead.

Step 1. Access Safe Mode with Networking

Manual malware removal should be best performed in the Safe Mode environment. 

Windows 7 / Vista / XP

  1. Click Start > Shutdown > Restart > OK.
  2. When your computer becomes active, start pressing F8 button (if that does not work, try F2, F12, Del, etc. – it all depends on your motherboard model) multiple times until you see the Advanced Boot Options window.
  3. Select Safe Mode with Networking from the list.Windows 7/XP

Windows 10 / Windows 8

  1. Right-click on Start button and select Settings.
    Settings
  2. Scroll down to pick Update & Security.
    Update and security
  3. On the left side of the window, pick Recovery.
  4. Now scroll down to find Advanced Startup section.
  5. Click Restart now.
    Reboot
  6. Select Troubleshoot.Choose an option
  7. Go to Advanced options.Advanced options
  8. Select Startup Settings.Startup settings
  9. Press Restart.
  10. Now press 5 or click 5) Enable Safe Mode with Networking.Enable safe mode

Step 2. Shut down suspicious processes

Windows Task Manager is a useful tool that shows all the processes running in the background. If malware is running a process, you need to shut it down:

  1. Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
  2. Click on More details.
    Open task manager
  3. Scroll down to Background processes section, and look for anything suspicious.
  4. Right-click and select Open file location.
    Open file location
  5. Go back to the process, right-click and pick End Task.
    End task
  6. Delete the contents of the malicious folder.

Step 3. Check program Startup

  1. Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
  2. Go to Startup tab.
  3. Right-click on the suspicious program and pick Disable.
    Startup

Step 4. Delete virus files

Malware-related files can be found in various places within your computer. Here are instructions that could help you find them:

  1. Type in Disk Cleanup in Windows search and press Enter.
    Disk cleanup
  2. Select the drive you want to clean (C: is your main drive by default and is likely to be the one that has malicious files in).
  3. Scroll through the Files to delete list and select the following:

    Temporary Internet Files
    Downloads
    Recycle Bin
    Temporary files

  4. Pick Clean up system files.
    Delete temp files
  5. You can also look for other malicious files hidden in the following folders (type these entries in Windows Search and press Enter):

    %AppData%
    %LocalAppData%
    %ProgramData%
    %WinDir%

After you are finished, reboot the PC in normal mode.

Finally, you should always think about the protection of crypto-ransomwares. In order to protect your computer from Cadq and other ransomwares, use a reputable anti-spyware, such as ReimageIntego, SpyHunter 5Combo Cleaner or Malwarebytes

How to prevent from getting Cadq ransomware

Protect your privacy – employ a VPN

There are several ways how to make your online time more private – you can access an incognito tab. However, there is no secret that even in this mode, you are tracked for advertising purposes. There is a way to add an extra layer of protection and create a completely anonymous web browsing practice with the help of Private Internet Access VPN. This software reroutes traffic through different servers, thus leaving your IP address and geolocation in disguise. Besides, it is based on a strict no-log policy, meaning that no data will be recorded, leaked, and available for both first and third parties. The combination of a secure web browser and Private Internet Access VPN will let you browse the Internet without a feeling of being spied or targeted by criminals. 

No backups? No problem. Use a data recovery tool

If you wonder how data loss can occur, you should not look any further for answers – human errors, malware attacks, hardware failures, power cuts, natural disasters, or even simple negligence. In some cases, lost files are extremely important, and many straight out panic when such an unfortunate course of events happen. Due to this, you should always ensure that you prepare proper data backups on a regular basis.

If you were caught by surprise and did not have any backups to restore your files from, not everything is lost. Data Recovery Pro is one of the leading file recovery solutions you can find on the market – it is likely to restore even lost emails or data located on an external device.

About the author
Jake Doevan
Jake Doevan - Computer technology expert

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