What Is Cuag Virus?
Cuag virus is a ransomware virus, that belongs to a large family of threats, commonly referred to as STOP/DJVU cryptoviruses. It’s me purpose once it lands on your machine is to increase different types of files in order to extort you into paying a lot of money in the form of bitcoin as a ransom pay off to get the files to work again. The main activity of this is that the virus enters your computer and silently changes the data of your files, adding the .cuag file extension and the _readme.txt ransom note, which contains instructions on how to pay the ransom.
This article to learn more information about this ransomware infection and how you can remove it from your computer system and try to decrypt your files for free.
Cuag Virus Summary
| Name | Cuag virus, also known as UDS:Trojan.Win32.Chapak.gen, Ransom:Win32/StopCrypt.KM!MTB, Win32:PWSX-gen [Trj], Win32:PWSX-gen [Trj], A Variant Of Win32/GenKryptik.FHJB – more detections of this virus on VirusTotal |
| File Extension | .cuag |
| Type | Ransomware, Cryptovirus |
| Short Description | The ransomware encrypts files on your computer system and demands a ransom to be paid to allegedly recover them. |
| Symptoms | The Cuag Virus ransomware will encrypt your files by appending the .cuag extension to them. |
| Ransom Demanding Note | _readme.txt |
| Distribution Method | Spam Emails, Email Attachments |
| Detection Tool |
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Cuag Virus – How Did I Get Infected?
Cuag virus is very similar to other recently detected versions of this family, like .bbbw, .bbbe and .bbbr ones.
Cuag virus may end up on your computer by being sent to you in the form of an email attachment that may pretend to be a legitimate document, that is often outlined as an important file, for example:
- Work-related files.
- “Password changed” types of e-mails.
- Receipts.
- Invoices.
- Flight tickets.
- Train tickets.
- Documents for an upcoming event.
If this is the case and you download an open this document, the following macro infection process may be triggered:
Another way to get infected with this virus if you download and run some type of a file that is posted on a third-party software download website. If this is the case, then it is very likely that the virus may pretend to be one of the following executables:
- SFX or other archives carrying game mods or similar files.
- Fake installers.
- Portable versions of programs that are cracked.
- Software crackfixes.
- Keygens for programs or games.
- Patches.
Cuag Virus – What Does It Do?
Cuag virus may be activated on your machine without you even realising it and it’s first activity is to set it payload files in one of the following Windows directories:
- %LocalLow%
- %AppData%
- %Windows%
- %SystemDrive%
- %Local%
- %Temp%
- %System%
- %system32%
These files can often be randomly named and they are downloaded from the server of the cyber criminals without you even realizing it.
The virus may also leave behind its ransom note file, that is known as _readme.txt and contains the extortion message:
Not just this, but this virus may also attack your Windows Registry Editor. It may make changes to different settings this way, but the main subkeys that it could attack or the following ones:
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
If the virus adds value strings and those keys, this means that it could run automatically each time you perform a system start up.
What Are .cuag Files
The Cuag files are encrypted using AES encryption algorithm. The virus does this by scanning for the files outside of the system directories of Windows, that may be of the following types:
- Audio file formats (.mp3, .wav, etc.).
- Pictures (.jpg, .png, .etc).
- Video file kinds (.mp4, .avi, etc.).
- Archive file types (.zip, .rar, etc).
- Documents of all sorts (.docx, .pptx, etc.).
- Other files.
After the encryption, a unique decryption key is generated, there is two kinds, online and off-line. The files look like the following:
Picture.jpg.Cuag virus
How to Remove Cuag Virus?
If you want to get rid of this virus as soon as possible from your computer system, our main suggestion is to follow the removal instructions that have been created underneath this guide. These steps are made with the main idea to provide you with the necessary information it takes to get rid of the virus either by yourself or automatically. If you want the removal with maximum effectiveness then we would advise the same as most cyber security experts would – to scan your computer by using an advanced anti-malware software. Such a professional tool is created to thoroughly scan your device and automatically take care of any threats in it.
How to Decrypt .cuag Files?
Cuag virus files can be decrypted, in case the key that is used to unlock the files is off-line. If so, we strongly suggest that you follow the STOP Ransomware File Decryption Guide or watch the guide video below. They contain the necessary steps to use the official decryptor of the virus, that is created by independent and reputable anti-malware researchers.
Video guide for using the STOP Ransomware Decryptor:
If you cannot recover your files via this method, we would suggest that you try the alternative steps below. They may not be 100% effective to recover all of your files, but with their help you could restore at least some of them.
Ventsislav Krastev
Ventsislav is a cybersecurity expert at SensorsTechForum since 2015. He has been researching, covering, helping victims with the latest malware infections plus testing and reviewing software and the newest tech developments. Having graduated Marketing as well, Ventsislav also has passion for learning new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management, Network Administration and Computer Administration of System Applications, he found his true calling within the cybersecrurity industry and is a strong believer in the education of every user towards online safety and security.
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Step 1: Scan for Cuag virus with SpyHunter Anti-Malware Tool
Ransomware Automatic Removal - Video Guide
Step 2: Uninstall Cuag virus and related malware from Windows
Here is a method in few easy steps that should be able to uninstall most programs. No matter if you are using Windows 10, 8, 7, Vista or XP, those steps will get the job done. Dragging the program or its folder to the recycle bin can be a very bad decision. If you do that, bits and pieces of the program are left behind, and that can lead to unstable work of your PC, errors with the file type associations and other unpleasant activities. The proper way to get a program off your computer is to Uninstall it. To do that:
Follow the instructions above and you will successfully delete most unwanted and malicious programs.
Step 3: Clean any registries, created by Cuag virus on your computer.
The usually targeted registries of Windows machines are the following:
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
You can access them by opening the Windows registry editor and deleting any values, created by Cuag virus there. This can happen by following the steps underneath:
Tip: To find a virus-created value, you can right-click on it and click "Modify" to see which file it is set to run. If this is the virus file location, remove the value.
Before starting "Step 4", please boot back into Normal mode, in case you are currently in Safe Mode.
This will enable you to install and use SpyHunter 5 successfully.
Step 4: Boot Your PC In Safe Mode to isolate and remove Cuag virus
Step 5: Try to Restore Files Encrypted by Cuag virus.
Method 1: Use STOP Decrypter by Emsisoft.
Not all variants of this ransomware can be decrypted for free, but we have added the decryptor used by researchers that is often updated with the variants which become eventually decrypted. You can try and decrypt your files using the instructions below, but if they do not work, then unfortunately your variant of the ransomware virus is not decryptable.
Follow the instructions below to use the Emsisoft decrypter and decrypt your files for free. You can download the Emsisoft decryption tool linked here and then follow the steps provided below:
1 Right-click on the decrypter and click on Run as Administrator as shown below:
2. Agree with the license terms:
3. Click on "Add Folder" and then add the folders where you want files decrypted as shown underneath:
4. Click on "Decrypt" and wait for your files to be decoded.
Note: Credit for the decryptor goes to Emsisoft researchers who have made the breakthrough with this virus.
Method 2: Use data recovery software
Ransomware infections and Cuag virus aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested a data recovery method that may help you go around direct decryption and try to restore your files. Bear in mind that this method may not be 100% effective but may also help you a little or a lot in different situations.
Simply click on the link and on the website menus on the top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.
Cuag virus-FAQ
What is Cuag virus Ransomware?
Cuag virus is a ransomware infection - the malicious software that enters your computer silently and blocks either access to the computer itself or encrypt your files.
Many ransomware viruses use sophisticated encryption algorithms to make your files inaccessible. The goal of ransomware infections is to demand that you pay a ransom payment to get access to your files back.
What Does Cuag virus Ransomware Do?
Ransomware in general is a malicious software that is designed to block access to your computer or files until a ransom is paid.
Ransomware viruses can also damage your system, corrupt data and delete files, resulting in the permanent loss of important files.
How Does Cuag virus Infect?
Via several ways.Cuag virus Ransomware infects computers by being sent via phishing emails, containing virus attachment. This attachment is usually masked as an important document, like an invoice, bank document or even a plane ticket and it looks very convincing to users.
Another way you may become a victim of Cuag virus is if you download a fake installer, crack or patch from a low reputation website or if you click on a virus link. Many users report getting a ransomware infection by downloading torrents.
How to Open .Cuag virus files?
You can't without a decryptor. At this point, the .Cuag virus files are encrypted. You can only open them once they are decrypted using a specific decryption key for the particular algorithm.
What to Do If a Decryptor Does Not Work?
Do not panic, and backup the files. If a decryptor did not decrypt your .Cuag virus files successfully, then do not despair, because this virus is still new.
Can I Restore ".Cuag virus" Files?
Yes, sometimes files can be restored. We have suggested several file recovery methods that could work if you want to restore .Cuag virus files.
These methods are in no way 100% guaranteed that you will be able to get your files back. But if you have a backup, your chances of success are much greater.
How To Get Rid of Cuag virus Virus?
The safest way and the most efficient one for the removal of this ransomware infection is the use a professional anti-malware program.
It will scan for and locate Cuag virus ransomware and then remove it without causing any additional harm to your important .Cuag virus files.
Can I Report Ransomware to Authorities?
In case your computer got infected with a ransomware infection, you can report it to the local Police departments. It can help authorities worldwide track and determine the perpetrators behind the virus that has infected your computer.
Below, we have prepared a list with government websites, where you can file a report in case you are a victim of a cybercrime:
Cyber-security authorities, responsible for handling ransomware attack reports in different regions all over the world:
Germany - Offizielles Portal der deutschen Polizei
United States - IC3 Internet Crime Complaint Centre
United Kingdom - Action Fraud Police
France - Ministère de l'Intérieur
Italy - Polizia Di Stato
Spain - Policía Nacional
Netherlands - Politie
Poland - Policja
Portugal - Polícia Judiciária
Greece - Cyber Crime Unit (Hellenic Police)
India - Mumbai Police - CyberCrime Investigation Cell
Australia - Australian High Tech Crime Center
Reports may be responded to in different timeframes, depending on your local authorities.
Can You Stop Ransomware from Encrypting Your Files?
Yes, you can prevent ransomware. The best way to do this is to ensure your computer system is updated with the latest security patches, use a reputable anti-malware program and firewall, backup your important files frequently, and avoid clicking on malicious links or downloading unknown files.
Can Cuag virus Ransomware Steal Your Data?
Yes, in most cases ransomware will steal your information. It is a form of malware that steals data from a user's computer, encrypts it, and then demands a ransom in order to decrypt it.
In many cases, the malware authors or attackers will threaten to delete the data or publish it online unless the ransom is paid.
Can Ransomware Infect WiFi?
Yes, ransomware can infect WiFi networks, as malicious actors can use it to gain control of the network, steal confidential data, and lock out users. If a ransomware attack is successful, it could lead to a loss of service and/or data, and in some cases, financial losses.
Should I Pay Ransomware?
No, you should not pay ransomware extortionists. Paying them only encourages criminals and does not guarantee that the files or data will be restored. The better approach is to have a secure backup of important data and be vigilant about security in the first place.
What Happens If I Don't Pay Ransom?
If you don't pay the ransom, the hackers may still have access to your computer, data, or files and may continue to threaten to expose or delete them, or even use them to commit cybercrimes. In some cases, they may even continue to demand additional ransom payments.
Can a Ransomware Attack Be Detected?
Yes, ransomware can be detected. Anti-malware software and other advanced security tools can detect ransomware and alert the user when it is present on a machine.
It is important to stay up-to-date on the latest security measures and to keep security software updated to ensure ransomware can be detected and prevented.
Do Ransomware Criminals Get Caught?
Yes, ransomware criminals do get caught. Law enforcement agencies, such as the FBI, Interpol and others have been successful in tracking down and prosecuting ransomware criminals in the US and other countries. As ransomware threats continue to increase, so does the enforcement activity.
About the Cuag virus Research
The content we publish on SensorsTechForum.com, this Cuag virus how-to removal guide included, is the outcome of extensive research, hard work and our team’s devotion to help you remove the specific malware and restore your encrypted files.
How did we conduct the research on this ransomware?
Our research is based on an independent investigation. We are in contact with independent security researchers, and as such, we receive daily updates on the latest malware and ransomware definitions.
Furthermore, the research behind the Cuag virus ransomware threat is backed with VirusTotal and the NoMoreRansom project.
To better understand the ransomware threat, please refer to the following articles which provide knowledgeable details.
As a site that has been dedicated to providing free removal instructions for ransomware and malware since 2014, SensorsTechForum’s recommendation is to only pay attention to trustworthy sources.
How to recognize trustworthy sources:
- Always check "About Us" web page.
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