Cadq is a DJVU family of ransomware-type infections. This variant encrypts important personal files (video, photos, documents). And encrypted files can be tracked by specific “.cadq” extension. So, you can’t obtain access to them at all. In this article I will try to help you remove Cadq ransomware for free. Also I will show you decrypt and restore encrypted files.

It is better to prevent, than repair and repent!

When we talk about the intrusion of unfamiliar programs into your computer’s work, the proverb “Forewarned is forearmed” describes the situation as accurately as possible. Gridinsoft Anti-Malware is exactly the tool that is always useful to have in your armory: fast, efficient, up-to-date. It is appropriate to use it as an emergency help at the slightest suspicion of infection.

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Most often, this virus infects countries such as Indonesia, Turkey and Brazil. I have prepared a translation of this article in your own language. You will find links for translation at the end of the article.

This Article Contains:

Cadq virus

Cadq can be correctly identify as a STOP/DJVU ransomware-type infection.

Cadq

🤔 Cadq virus is ransomware that originates from the DJVU/STOP family. Its primary purpose is to encrypt files that are important for you. After that ransomware virus asks its victims for a ransom fee ($490 – $980) in BitCoin.

A ransomware is a specific kind of malware ☝️ that encrypted your documents and then forces you to pay to restore them. The Djvu/STOP ransomware family was first revealed and analyzed by virus analyst Michael Gillespie.

Cadq virus is similar to other representatives of the same DJVU family: Ribd, Ygkz, Reig, Cosd, Plam. This virus encrypt all common file types and adds its particular “.cadq” extension into all files. For example, the file “1.jpg”, will be amended into “1.jpg.cadq“. As soon as the encryption is successfully accomplished, virus creates a specific text file “_readme.txt” and puts it into all folders that contain the modified files.

Name	Cadq Virus
Extension	.cadq file virus
Contact	helpteam@mail.ch, helpmanager@airmail.cc
Ransomware note	_readme.txt
Ransom	From $490 to $980 (in Bitcoins)
Ransomware family ¹	DJVU/STOP ² ransomware
Detection	Graftor.232526, Win32/CoinMiner.AJQ, Razy.667589
Symptoms	Encrypted most of your files (photos, videos, documents) and adds a particular “.cadq” extension; Can delete Volume Shadow copies to make victim’s attempts to restore data impossible; Adds a list of domains to HOSTS file to block access to certain security-related sites; Installs password-stealing Trojan on the system, like Azorult Spyware;
Fix Tool	To remove malware infections, scan your PC with legitimate antivirus. I recommend using GridinSoft. GridinSoft Anti-Malware To use full-featured product, you have to purchase a license. 6-day free trial available.

The image below gives a clear vision of how the files with the “.cadq” extension look like:

Cadq File (STOP/DJVU Ransomware)

This text asking payment is for restore files via decryption key:

_readme.txt (STOP/DJVU Ransomware) – The scary alert demanding from users to pay the ransom to decrypt the encoded data contains these frustrating warnings

The cryptography algorithm used by DJVU/STOP ransomware is AES-256. So, if your data got encrypted with an online decryption key, which is totally distinct. The sad reality is that it is impossible to decrypt the files without the unique key.

If Cadq worked in online mode, you can’t gain access to the AES-256 key. It is stored on a remote server owned by the frauds who promote the Cadq ransomware.

For receiving decryption key the payment should be $980. To obtain the payment details, the victims are encouraged by the message to contact the frauds by email (helpteam@mail.ch).

The message by the ransomware states the following information:

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-WJa63R98Ku

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:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Do not pay a ransom

Please, try to use the available backups, or Decrypter tool

_readme.txt file also indicates that the computer owners must get in touch with the Cadq representatives during 72 hours starting from the moment files were encrypted. On the condition of getting in touch within 72 hours, users will be granted a 50% rebate. Thus Extortioners will minimize the ransom amount down to $490). Yet, stay away from paying the ransom!

I definitely advise that you do not contact these crooks and do not pay. The one of the most real working solution to recover the lost data – just using the available backups, or use Decrypter tool.

The peculiarity of all such viruses applies a similar set of actions to generate the unique decryption key to recover the ciphered data.

Thus, unless the ransomware is still under the stage of development or possesses some hard-to-track flaws, manually recovering the ciphered data is a thing you can’t perform. The only solution to prevent the loss of your valuable data is to make backups of your crucial files regularly.

Note that even if you do maintain such backups regularly, they ought to be put into a specific location without loitering, not being connected to your main workstation.

For instance, you may keep the backup on the USB flash drive or some alternative external hard drive storage. Optionally, you may refer to the help of online (cloud) information storage.

Needless to mention, when you maintain your backup data on your common device, it may be similarly ciphered as well as other data.

For this reason, locating the backup on your main PC is surely not a good idea.

How I was infected?

Ransomware has a various methods to built into your system. But it doesn’t really matter what way had place in your case.

Cadq ransomware attack following a successful phishing attempt.

Nevertheless, these are the common leaks through which it may be injected into your PC:

hidden installation along with other apps, especially the utilities that work as freeware or shareware;
dubious link in spam emails leading to the virus installer
online free hosting resources;
using illegal peer-to-peer (P2P) resources for downloading pirated software.

There were cases when the Cadq virus was disguised as some legitimate tool, for example, in the messages demanding to initiate some unwanted software or browser updates. This is typically the way how some online frauds aim to force you into installing the Cadq ransomware manually, by actually making you directly participate in this process.

Surely, the bogus update alert will not indicate that you are actually going to inject the virus. This installation will be concealed under some alert mentioning that allegedly you should update Adobe Flash Player or some other dubious program whatsoever.

Of course, the cracked apps represent the damage too. Using P2P is both illegal and may result in the injection of serious malware, including the Cadq ransomware.

To sum up, what can you do to avoid the Cadq ransomware injection into your device? Even though there is no 100% guarantee to prevent your PC from getting damaged, there are certain tips I want to give you to prevent the Cadq penetration. You must be cautious while installing free software today.

Make sure you always read what the installers offer in addition to the main free program. Stay away from opening dubious email attachments. Do not open files from the unknown addressees. Of course, you must always update your current security program.

The malware does not speak openly about itself. It will not be mentioned in the list of your available programs. However, it will be masked under some malicious process running regularly in the background, starting from the moment when you launch your PC.

Instant automatic CADQ virus removal

In addition to encode a victim’s files, the Cadq virus has also started to install the Azorult Spyware on system to steal account credentials, cryptocurrency wallets, desktop files, and more.³

Reasons why I would recommend GridinSoft⁴
The is an excellent way to deal with recognizing and removing threats – using Gridinsoft Anti-Malware. This program will scan your PC, find and neutralize all suspicious processes⁵.

Download Virus Removal Tool.
You can download GridinSoft Anti-Malware by clicking the button below:
Download GridinSoft Anti-Malware
Run the setup file.
When setup file has finished downloading, double-click on the setup-antimalware-fix.exe file to install GridinSoft Anti-Malware on your computer.

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.
Press “Install” button.

Once installed, Anti-Malware will automatically run.

Wait for the Anti-Malware scan to complete.
GridinSoft Anti-Malware will automatically start scanning your PC for Cadq infections and other malicious programs. This process can take a 20-30 minutes, so I suggest you periodically check on the status of the scan process.
Click on “Clean Now”.
When the scan has finished, 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.

Trojan Killer for special instances

In some certain instances, Cadq ransomware can block the running of setup files of different anti-malware programs. In this situation, you need to utilize the removable drive with a pre-installed antivirus tool.

There is a minimal number of security tools that can be set up on USB drives, and antiviruses that can do so in most cases require obtaining quite an expensive license. For this instance, I can recommend you to use another solution of GridinSoft – Trojan Killer Portable. It has a 14-days cost-free trial mode that offers the entire features of the paid version ⁶. This term will definitely be 100% enough to wipe malware out.

CADQ ransomware decryption tool

Restore solution for big “.cadq files“

Try removing .cadq extension on a few BIG files and opening them. Either the Cadq infection read and did not encrypt the file, or it bugged and did not add the filemarker. If your files are very large (2GB+), the latter is most likely. Please, let me know in comments if that will work for you.

The newest extensions released around the end of August 2019 after the criminals made changes. This includes Pola, Pola, Wbxd, etc.

As a result of the changes made by the criminals, STOPDecrypter is no longer supported. It has been removed and replaced with the Emsisoft Decryptor for STOP Djvu Ransomware developed by Emsisoft and Michael Gillespie.

You can download free decryption tool here: Decryptor for STOP Djvu.

Download and run decryption tool.

Start downloading the decryption tool.

Make sure to launch the decryption utility as an administrator. You need to agree with the license terms that will come up. For this purpose, click on the “Yes” button:

As soon as you accept the license terms, the main decryptor user interface comes up:

Select folders for decryption.

Based on the default settings, the decryptor will automatically populate the available locations to decrypt the currently available drives (the connected ones), including the network drives. you can select extra (optional) locations with the help of the “Add” button.

Decryptors normally suggest several options considering the specific malware family. The current possible options are presented in the Options tab and can be activated or deactivated there. You may locate a detailed list of the currently active Options below.

Click on the “Decrypt” button.

As soon as yo add all the desired locations for decryption into the list, click on the “Decrypt” button in order to initiate the decryption procedure.

Note that the main screen may turn you to a status view, letting you know of the active process and the decryption statistics of your data:

The decryptor will notify you as soon as the decryption procedure is completed. If you need the report for your personal papers, you can save it by choosing the “Save log” button. Note that it is also possible to copy it directly to your clipboard and to paste it into emails or messages here if you need to do so.

The Emsisoft Decryptor might display different messages after a failed attempt to restore your cadq files:

✓ Error: Unable to decrypt file with ID: [your ID]

There is no corresponding decryption key in the Emsisoft decryptor’s database.

✓ No key for New Variant online ID: [your ID]

Notice: this ID appears to be an online ID, decryption is impossible

Your original files were encrypted with an online key. So no one else has the same encryption/decryption key pair. Recovery of cadq files without paying the criminals is impossible. 🙁

✓ Result: No key for new variant offline ID: [example ID]

This ID appears to be an offline ID. Decryption may be possible in the future.

An offline key was used, but files could not be restored (the offline decryption key isn’t available yet). But, receiving this message is good news for you because it might be possible to restore your CADQ files in the future. 🙂
It can take a few weeks or months until the decryption key gets found and uploaded to the decryptor. Please follow updates regarding the decryptable DJVU versions here.

✓ Remote name could not be resolved

It’s an indication of a DNS issue on your PC. Our first recommendation is to reset your HOSTS file back to default.

Restoring CADQ files with data recovery tools

In some case Cadq ransomware is not doom for your files…

Cadq ransomware encryption mechanism feature is next: it encrypts every file byte-by-byte, then saves a file copy, deleting (and not overriding!) the original file. Hence, the physical disk’s file location information is lost, but the original file is not deleted from the physical disk. The cell, or the sector where this file was stored, can still contain this file, but it is not listed by the file system and can be overwritten by data that has been loaded to this disk after the deletion. Hence, it is possible to recover your files using special software.

I recently had my pc infected by the Cadq virus. It managed to bypass 2 Antivirus software and 2 malware fighters. Anyway, after realizing it was an online algorithm, it is impossible to retrieve my encrypted files. I also had my backup drive plugged in at the time of the virus, and this was also infected .. or so I thought. Every folder within my backup drive had been infected and was encrypted. However, despite losing some important files, I retrieved almost 80% of my 2TB storage. When I started going through the folders, I noticed the readme.txt ransom note in every folder. I opened some of the folders and found that all files that were not in a subfolder within that folder had been encrypted. However, I found a flaw and glimmer of hope when I went into the subfolders in other folders and found that these files had not been encrypted. Every folder within my c and d drives, including subfolders, had been encrypted, but this was not the case with the backup drive. Having subfolders created within a folder has saved 80% of my data. As I said, I believe this to be only a small loophole on a backup drive. I’ve since found a further 10 % of my data on another hard drive on a different pc. So my advice is if you use a backup drive, create subfolders. I was lucky, I guess. But I was also unlucky that the virus hit as I transferred some files from my back up. Hopefully, this can help some other people in my situation.Jamie Newland

Some pointers for recovery repair of Cadq files (true for all STOP/DJVU variants):

I have seen Cadq variants fail to encrypt deeper nested folders so that you can check that. You may find those are not encrypted.

This ransomware saves encrypted data to a new file, deletes the original. So there’s a slight chance part of that deleted file can be recovered using file recovery software. It’s unlikely the folder structure can be restored, so a free tool like PhotoRec may be as good as any.

This ransomware only partially encrypts (about first 150 KB), so depending on file size and type of data, the not encrypted part may be recoverable.

Joep

Recovering files with PhotoRec tool

PhotoRec is an open-source program, which is created for file recovery from damaged disks or for file recovery in case if they are deleted. However, as time has gone by, this program can recover the files of 400 different extensions. Hence, it can be used for data recovery after the ransomware attack

At first, you need to download this app. It is 100% free, but the developer states that there is no guarantee that your files will be recovered. PhotoRec is distributed in a pack with other utility of the same developer – TestDisk. The downloaded archive will have the TestDisk name, but don’t worry. PhotoRec files are right inside.

To open PhotoRec, you need to find and open “qphotorec_win.exe” file. No installation is required – this program has all the files it need inside of the archive, hence, you can fit it on your USB drive, and try to help your friend/parents/anyone who was been attacked by DJVU/STOP ransomware.

After the launch, you will see the screen showing you the full list of your disk spaces. However, this information is likely useless because the required menu is placed a bit higher. Click this bar, then choose the disk which was attacked by ransomware.

After choosing the disk, you need to choose the destination folder for the recovered files. This menu is located at the lower part of the PhotoRec window. The best desicion is to export them on USB drive or any other type of removable disk.

Then, you need to specify the file formats. This option is located at the bottom, too. As it was mentioned, PhotoRec can recover files of about 400 different formats.

Finally, you can start files recovery by pressing the “Search” button. You will see the screen where the results of the scan and recovery are shown.

Cadq files recovery guide

Frequently Asked Questions

🤔 How can I open “.cadq” files?

No way. These files are modified by ransomware. The contents of .cadq files are not available until they are decrypted.

🤔 Cadq files contain important information. How can I decrypt them urgently?

If your data remained in the .cadq files very valuable, you most likely made a backup copy.
If not, then you can try to restore them through the system function – Restore Point.
All other methods will require patience.

🤔 You have advised using GridinSoft Anti-Malware to remove Cadq. Does this mean that the program will delete my encrypted files?

Of course not. Your encrypted files do not pose a threat to the computer. What happened has already happened.

You need GridinSoft Anti-Malware to remove active system infections. The virus that encrypted your files is most likely still active and periodically runs a test for the ability to encrypt even more files. Also, these viruses install keyloggers and backdoors for further malicious actions (for example, theft of passwords, credit cards) often.

🤔 Cadq ransomware has blocked the infected PC: I can’t get the activation code.

In this situation, you need to prepare the memory stick with a pre-installed Trojan Killer.

🤔 Decryptor did not decrypt all my files, or not all of them were decrypted. What should I do?

Have patience. You are infected with the new version of STOP/DJVU ransomware, and decryption keys have not yet been released. Follow the news on our website.

We will keep you posted on when new Cadq keys or new decryption programs appear.

🤔 What can I do right now?

The Cadq ransomware encrypts only the first 150KB of files. So MP3 files are rather large. Some media players (Winamp, for example) may be able to play the files, but – the first 3-5 seconds (the encrypted portion) will be missing.

You can try to find a copy of an original file that was encrypted:

Files you downloaded from the Internet that were encrypted, and you can download again to get the original.
Pictures that you shared with family and friends that they can send back to you.
Photos that you uploaded on social media or cloud services like Carbonite, OneDrive, iDrive, Google Drive, etc.)
Attachments in emails you sent or received and saved.
Files on an older computer, flash drive, external drive, camera memory card, or iPhone where you transferred data to the infected computer.

Also, you can contact the following government fraud and scam sites to report this attack:

In the United States: On Guard Online;
In Canada: Canadian Anti-Fraud Centre;
In the United Kingdom: Action Fraud;
In Australia: SCAMwatch;
In New Zealand: Consumer Affairs Scams;
In India, go to Indian National Cybercrime Reporting Portal.
In France: Agence nationale de la sécurité des systèmes d’information;
In Poland: KOMENDA GŁÓWNA POLICJI;
In Portugal: Polícia Judiciária;
In Italy: Polizia di Stato;
In Spain: Cuerpo Nacional de Policía;
In Germany: Bundesamt für Sicherheit in der Informationstechnik;
In Ireland: An Garda Síochána;

Here is the list of documents/information that is needed for filling the report:

Date and time of attack (at least approximated if you haven’t met the exact moment);
Way of ransomware injection – email spamming, RDP vulnerability exploiting, network vulnerability exploiting, et cetera;
Copy of money ransom note (a.k.a. readme.txt), or copy of email that was sent by ransomware distributors after contacting the specified email address;
Extension that is added by ransomware to your files;
Email addresses that is supposed to be used for getting information about the file decryption;
Bitcoin wallet address that is supposed to be used to get the ransom;
The amount of ransom to be paid;
Name of your organization, its size and contact information;
Total loss your company carried because of ransomware attack.

To report the attack, you can contact local executive boards (A full list you can find here). For instance, if you live in USA, you can have a talk with FBI Local field office, IC3 or Secret Service.

Video instruction

It’s my favorite video tutorial: How to use GridinSoft Anti-Malware and Emsisoft Decryptor for fix ransomware infections.

If the guide doesn’t help you to remove Cadq infection, please download the GridinSoft Anti-Malware that I recommended. Also, you can always ask me in the comments for getting help.

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Brendan Smith

CADQ Ransomware — How To Restore & Decrypt Files?

Name: CADQ Virus

Description: CADQ Virus is a DJVU family of ransomware-type infections. This infection encrypts important personal files (video, photos, documents). The encrypted files can be tracked by a specific .cadq extension. So, you can't use them at all. After that CADQ virus asks its victims for a ransom fee ($490 - $980) in BitCoin.

Operating System: Windows

Application Category: Virus

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References

My files are encrypted by ransomware, what should I do now?
About DJVU (STOP) Ransomware.
Windows passwords vulnerability (Mimikatz HackTool): https://howtofix.guide/mimikatz-hacktool/
GridinSoft Anti-Malware Review from HowToFix site: https://howtofix.guide/gridinsoft-anti-malware/
More information about GridinSoft products: https://gridinsoft.com/comparison
Trojan Killer Review: https://howtofix.guide/trojan-killer/

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