GANDCRAB V4 Ransomware – Remove and Restore .KRAB Encrypted Files

Vencislav Krustev

Ventsislav has been covering the latest malware, software and newest tech developments at SensorsTechForum for 3 years now. He started out as a network administrator. Having graduated Marketing as well, Ventsislav also has passion for discovery of new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management and then Network Administration, he found his passion within cybersecrurity and is a strong believer in basic education of every user towards online safety.

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This article has been written with the main goal of helping you understand what is the GANDCRAB V4 ransomware virus and how to effectively remove it from your PC plus how you can attempt to recover .KRAB files, encrypted by this iteration.

GANDCRAB has successfully come out in a new version, using the .KRAB file extension. With this new version, the ransomware virus, demanding victims to pay the ransom in the DASH cryptocurrency, has become one of the biggest ransomware viruses alongside big ransomware families like WannaCry, Dharma, CryptoWall and CryptoLocker. The main purpose of .KRAB this version of GANDCRAB is to encrypt your data. Typically, the ransomware drops a ransom note file, called KRAB-DECRYPT.txt, which aims to extort victims to pay a ransom “fee” to get the files to work again. If your computer has been infected by the GANDCRAB V4 ransomware virus, we strongly suggest that you read this article and learn how you can remove this malware effectively and how you can try and recover as many .KRAB encrypted files as possible, without paying the ransom.

Threat Summary

Name	GANDCRAB V4
Type	Ransomware, Cryptovirus
Short Description	New version of GandCrab ransomware. Encrypts the files, making them unable to be opened and asks victims to pay ransom in the DASH cryptocurrency to get the files to work again.
Symptoms	The GANDCRAB V4 virus leaves the files with the .KRAB file extension and drops a ransom note, called KRAB-DECRYPT.txt.
Distribution Method	Spam Emails, Email Attachments, Executable files
Detection Tool	See If Your System Has Been Affected by GANDCRAB V4 Download Malware Removal Tool
User Experience	Join Our Forum to Discuss GANDCRAB V4.
Data Recovery Tool	Windows Data Recovery by Stellar Phoenix Notice! This product scans your drive sectors to recover lost files and it may not recover 100% of the encrypted files, but only few of them, depending on the situation and whether or not you have reformatted your drive.

GANDCRAB V4 Virus – Update August 2018

The GANDCRAB V4 Virus continues to spread in August, 2018. Malware researchers suspect that more countries might be getting affected as more languages have been added to the payment page of the ransomware. You can clearly see that from the below screenshot:

If more languages are being added, either the cybercriminals are going to spread their malware in more countries (by using malvertising campaigns, for example) or they know that those countries are already affected by the GANDCRAB V4 Virus.

GANDCRAB V4 Virus – How Does It Infect Victims

The infection process of the .KRAB iteration of this ransomware is rather similar to the infection procedure that was used in its older versions. The ransomware authors aim to use a malicious attachment, often a Microsoft Office document or a .PDF file, whose main goal is to trick users to enable Macros. Such documents often deceive users that, unless editing is not enabled, they cannot read what is in the documents. One such file was detected by researcher Marcelo Rivero to be a receipt in a PDF file which then leads to infecting the user with GANDCRAB V4. The infection chain occurs as it follows:

The e-mails carrying the ransomware are spreading the attachment in a .7z archive file with the same name as the PDF document inside, as researcher from malware-traffic-analysis Brad has discovered. The messages in the e-mails themselves aim to convince the user that the attachment is of utmost importance and should be opened immediately. Below, you can see one of the e-mails carrying a malicious GANDCRAB attachment:

From: Deanna Bennett <>
Subject: Payment Invoice #93611
Attachment: DOC402942349491-PDF.7Z

Dear Customer,
To read your document please open the attachment and reply as soon as possible.
Kind regards,
TCR Customer Support

Naturally, there are other subjects and other e-mails as well, since the cyber-criminals who are behind GANDCRAB V4 have likely created a lot of e-mail templates in order to avoid having their e-mail addresses flagged by the e-mail providers’ detection software. Here are some of the topics (subjects) you are likely to encounter in an e-mail, carrying GANDCRAB V4 ransomware virus:

In addition to documents with malicious Macros, the GANDCRAB V4 ransomware may also infect you by simply clicking on the .7z file, since researchers have reported that the malware may self-extract a .JS (JavaScript) file with the same name which automatically starts the infection process:

GANDCRAB V4 Ransomware – Analysis

Once the malicious .JS file or the malicious macros that cause the infection with GANDCRAB V4 ransomware are executed, the ransomware virus begins its malicious activities. The .JS file drops an executable type of fil, which is often named randomly or resembles a legitimate Windows program. The location in which this file is dropped may be the the following:

→ C:\Users\{Your Username}\AppData\{malicious file name}.exe
HASH of the file: 97a910c50171124f2cd8cfc7a4f2fa4f

Then, the virus uses the “RunOnce” registry sub-key in which it adds the REG_SZ type of registry value. This is done with the purpose of getting the malicious file to run automatically on Windows boot. This procedure may result in the ransomware .exe running automatically on Windows login. The RunOnce subkeys in which you can find the value string have the following locations:

→ HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

The GANDCRAB V4 ransomware also makes sure that the victim reads its ransom note file, which contains instructions how to download and install Tor browser to anonymously pay the ransom in the DASH cryptocurrency by going on the ransomware’s web page. The note is called by two names – CRAB-DECRYPT.txt or KRAB-DECRYPT.txt and has the following message for the victims to see:

–= GANDCRAB V4 =—
Attention!
All your files, documents, photos, databases and other important files are encrypted and have the extension: .KRAB
The only method of recovering files is to purchase an unique private key. Only we can give you this key and only we can recover your files.
The server with your key is in a closed network TOR. You can get there by the following ways:
—————————————————————————————-
| 0. Download Tor browser – https://www.torproject.org/
| 1. Install Tor browser
| 2. Open Tor Browser
| 3. Open link in TOR browser:
| 4. Follow the instructions on this page
—————————————————————————————-
On our page you will see instructions on payment and get the opportunity to decrypt 1 file for free.
ATTENTION!
IN ORDER TO PREVENT DATA DAMAGE:
* DO NOT MODIFY ENCRYPTED FILES
* DO NOT CHANGE DATA BELOW
—BEGIN GANDCRAB KEY—
—END GANDCRAB KEY—
—BEGIN PC DATA—
—END PC DATA—

When the victim opens the web page in Tor browser, a similar web page to the other GANDCRAB variants is also seen with this version:

The web page also features a live chat and detailed instructions on how to pay the ransom to get the so-called GandCrab Decryptor:

GANDCRAB V4 Ransomware – Encryption Process

GANDCRAB ransomware uses a very sophisticated and well-developed encryption procedure which utilizes the combination of the following encryption algorithms:

• AES-256 (Advanced Encryption Standard)
• RSA-2048 (Rivest-Shamir-Adleman)

Both of the ciphers are respectively in the 256 bit and 2048 bit of strength, making them impossible to be decoded if you do not know the decryption keys. And to further complicate the situation, GANDCRAB V4 ransomware also encrypts the files in something known as CBC mode, or Cipher-Block Chaining mode. This mode chains up the encrypted files in a way that is tamper-proof. To best explain this, GANDCRAB V4 encrypts the files as it follows:

Step 1: The ransomware scans for the files it wants to encrypt (documents, videos, images, audio files, archives, etc.), while excluding files in Windows directories that may damage the functioning of your PC.
Step 2: GANDCRAB V4 encrypts the files by creating copies of the original files, which are with replaced blocks of data within them. The bad news is that the CBC mode links those blocks together and if the files are tampered with, the CBC mode breaks them indefinitely.
Step 3: After encryption, the ransomware generates a unique decryption key for each file; all files are likely linked in a KEY file, which is also encrypted, making it impossible to decrypt the files without the decryption key.
Step 4: GANDCRAB V4 ransomware adds the .KRAB file suffix to the encrypted copies of the files and deletes the original files. This makes the encrypted files to appear like the following:

Step 5: The virus likely triggers the following commands as an administrator in Windows Command Prompt:

→ sc stop VVS
sc stop wscsvc
sc stop WinDefend
sc stop wuauserv
sc stop BITS
sc stop ERSvc
sc stop WerSvc
cmd.exe /C bcdedit /set {default} recoveryenabled No
cmd.exe /C bcdedit /set {default} bootstatuspolicy ignoreallfailures
C:\Windows\System32\cmd.exe” /C vssadmin.exe Delete Shadows /All /Quiet

This is done with the purpose to delete the shadow volume copies of the infected machine, so that the user cannot restore the files, using Windows Recovery.

Remove GANDCRAB V4 Ransomware and Restore .KRAB Encrypted Files

Removing GANDCRAB V4 ransomware may be more complicated than it seems, since this ransomware virus may contain multiple defensive techniques that may damage your files and your computer indefinitely. One way to remove the ransomware manually is if you follow the manual removal instructions underneath this article and use the information to do the removal yourself. Keep in mind you must really know what you are doing, since you risk loosing your files indefinitely.

Another way to do the removal, which is often advised by security analysts, is to download and install an advanced anti-malware software. Such program will automatically scan for and remove all of the GANDCRAB V4-related virus files and make sure that the virus is safely removed from your computer.

If you want to restore your encrypted files, directly trying to decrypt them is not a good idea, unless there is an official decryptor available. Paying the ransom is one way to go with, but it is not advisable, mainly because you may not get your files after paying. By paying, you are also supporting the operation of the cyber-criminals as well. Thus, we suggest that you try out the alternative methods for file recovery underneath this article in step “2. Restore files, encrypted by GANDCRAB V4”. They have been created to help you try and restore the deleted original files by GANDCRAB V4 by using data recovery software to recover some or most of your files, depending on the condition of the deleted file. The methods are not 100% effective to recover your data, but their main goal is to help you to restore as many files as possible, as they have helped some of the users on our forums.

Note! Your computer system may be affected by GANDCRAB V4 and other threats.
Scan Your PC with SpyHunter
SpyHunter is a powerful malware removal tool designed to help users with in-depth system security analysis, detection and removal of threats such as GANDCRAB V4.
Keep in mind, that SpyHunter’s scanner is only for malware detection. If SpyHunter detects malware on your PC, you will need to purchase SpyHunter’s malware removal tool to remove the malware threats. Read our SpyHunter 5 review. Click on the corresponding links to check SpyHunter’s EULA, Privacy Policy and Threat Assessment Criteria.

To remove GANDCRAB V4 follow these steps:

1. Boot Your PC In Safe Mode to isolate and remove GANDCRAB V4 files and objects

Boot Your PC Into Safe Mode

1. For Windows XP, Vista and 7. 2. For Windows 8, 8.1 and 10. Fix registry entries created by malware and PUPs on your PC.

For Windows XP, Vista and 7 systems:

1. Remove all CDs and DVDs, and then Restart your PC from the “Start” menu.
2. Select one of the two options provided below:

– For PCs with a single operating system: Press “F8” repeatedly after the first boot screen shows up during the restart of your computer. In case the Windows logo appears on the screen, you have to repeat the same task again.

– For PCs with multiple operating systems: Тhe arrow keys will help you select the operating system you prefer to start in Safe Mode. Press “F8” just as described for a single operating system.

3. As the “Advanced Boot Options” screen appears, select the Safe Mode option you want using the arrow keys. As you make your selection, press “Enter“.

4. Log on to your computer using your administrator account

While your computer is in Safe Mode, the words “Safe Mode” will appear in all four corners of your screen.

Step 1: Open up the Start Menu.

Step 2: Click on the Power button (for Windows 8 it is the little arrow next to the “Shut Down” button) and whilst holding down “Shift” click on Restart.

Step 3: After reboot, a blue menu with options will appear. From them you should choose Troubleshoot.

Step 4: You will see the Troubleshoot menu. From this menu choose Advanced Options.

Step 5: After the Advanced Options menu appears, click on Startup Settings.

Step 6: From the Startup Settings menu, click on Restart.

Step 7: A menu will appear upon reboot. You can choose any of the three Safe Mode options by pressing its corresponding number and the machine will restart.

Some malicious scripts may modify the registry entries on your computer to change different settings. This is why cleaning your Windows Registry Database is recommended. Since the tutorial on how to do this is a bit long and tampering with registries could damage your computer if not done properly you should refer and follow our instructive article about fixing registry entries, especially if you are unexperienced in that area.

2. Find files created by GANDCRAB V4 on your PC

Find files created by GANDCRAB V4

1. For Windows 8, 8.1 and 10. 2. For Windows XP, Vista, and 7.

For Newer Windows Operating Systems

Step 1:

On your keyboard press  + R and write explorer.exe in the Run text box and then click on the Ok button.

Step 2:

Click on your PC from the quick access bar. This is usually an icon with a monitor and its name is either “My Computer”, “My PC” or “This PC” or whatever you have named it.

Step 3:

Navigate to the search box in the top-right of your PC’s screen and type “fileextension:” and after which type the file extension. If you are looking for malicious executables, an example may be “fileextension:exe”. After doing that, leave a space and type the file name you believe the malware has created. Here is how it may appear if your file has been found:

N.B. We recommend to wait for the green loading bar in the navination box to fill up in case the PC is looking for the file and hasn’t found it yet.

For Older Windows Operating Systems

In older Windows OS’s the conventional approach should be the effective one:

Step 1:

Click on the Start Menu icon (usually on your bottom-left) and then choose the Search preference.

Step 2:

After the search window appears, choose More Advanced Options from the search assistant box. Another way is by clicking on All Files and Folders.

Step 3:

After that type the name of the file you are looking for and click on the Search button. This might take some time after which results will appear. If you have found the malicious file, you may copy or open its location by right-clicking on it.

Now you should be able to discover any file on Windows as long as it is on your hard drive and is not concealed via special software.

Use SpyHunter to scan for malware and unwanted programs

3. Scan for malware and unwanted programs with SpyHunter Anti-Malware Tool

Scan your PC and Remove GANDCRAB V4 with SpyHunter Anti-Malware Tool and back up your data

1. Install SpyHunter to scan for GANDCRAB V4 and remove them.2. Scan with SpyHunter, Detect and Remove GANDCRAB V4. Back up your data to secure it from malware in the future.

Step 1: Click on the “Download” button to proceed to SpyHunter’s download page.

Download

Malware Removal Tool

It is recommended to run a scan before purchasing the full version of the software to make sure that the current version of the malware can be detected by SpyHunter. Click on the corresponding links to check SpyHunter’s EULA, Privacy Policy and Threat Assessment Criteria.

Step 2: Guide yourself by the download instructions provided for each browser.

Step 3: After you have installed SpyHunter, wait for it to update automatically.

Step 1: After the update process has finished, click on the ‘Malware/PC Scan’ tab. A new window will appear. Click on ‘Start Scan’.

Step 2: After SpyHunter has finished scanning your PC for any files of the associated threat and found them, you can try to get them removed automatically and permanently by clicking on the ‘Next’ button.

Step 3: If any threats have been removed, it is highly recommended to restart your PC.

Back up your data to secure it against attacks in the future

IMPORTANT! Before reading the Windows backup instructions, we highly recommend to back up your data with a cloud backup solution and insure your files against any type of loss, even from the most severe threats. We recommend you to read more about it and to download SOS Online Backup .

SOS Online Backup

4. Try to Restore files encrypted by GANDCRAB V4

Try to Restore Files Encrypted by GANDCRAB V4

Ransomware infections and GANDCRAB V4 aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested several alternative methods that may help you go around direct decryption and try to restore your files. Bear in mind that these methods may not be 100% effective but may also help you a little or a lot in different situations.

Method 1: Scanning your drive’s sectors by using Data Recovery software.
Another method for restoring your files is by trying to bring back your files via data recovery software. Here are some suggestions for preferred data recovery software solutions:

• Stellar Phoenix Data Recovery Technicians License(Pro version with more features)
• Stellar Phoenix Windows Data Recovery
• Stellar Phoenix Photo Recovery

Method 2: Trying Kaspersky and EmsiSoft’s decryptors.
If the first method does not work, we suggest trying to use decryptors for other ransomware viruses, in case your virus is a variant of them. The two primary developers of decryptors are Kaspersky and EmsiSoft, links to which we have provided below:

• Kaspersky Decryptors
• Emsisoft Decryptors

Method 3: Using Shadow Explorer

To restore your data in case you have backup set up, it is important to check for Volume Shadow Copies, if ransomware has not deleted them, in Windows using the below software:

• Shadow Explorer

Method 4: Finding the decryption key while the cryptovirus sends it over a network via a sniffing tool.

Another way to decrypt the files is by using a Network Sniffer to get the encryption key, while files are encrypted on your system. A Network Sniffer is a program and/or device monitoring data traveling over a network, such as its internet traffic and internet packets. If you have a sniffer set before the attack happened you might get information about the decryption key. See how-to instructions below:

Instructions on How to Find Decryption Key for Files Encrypted By Ransowmare

Vencislav Krustev

Ventsislav has been covering the latest malware, software and newest tech developments at SensorsTechForum for 3 years now. He started out as a network administrator. Having graduated Marketing as well, Ventsislav also has passion for discovery of new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management and then Network Administration, he found his passion within cybersecrurity and is a strong believer in basic education of every user towards online safety.

More Posts - Website

Vencislav Krustev

Ventsislav has been covering the latest malware, software and newest tech developments at SensorsTechForum for 3 years now. He started out as a network administrator. Having graduated Marketing as well, Ventsislav also has passion for discovery of new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management and then Network Administration, he found his passion within cybersecrurity and is a strong believer in basic education of every user towards online safety.

More Posts - Website

4 Comments

1. Lynne July 4, 2018 at 9:51 am

   I have a battery symbol in the top right corner of my phone. It is not the life of the battery it has what looks like 3 triangles in it. It appeared about a week ago. Please can you help.

   Reply ↓
2. anonimo August 21, 2018 at 9:48 pm

   es el ahorro de datos, saludos

   Reply ↓
3. Mohammad Yari August 29, 2018 at 2:02 pm

   My files are encrypted by gandcrab’s ransomware and there is currently no way to access my data. Dear custodians, I ask you to help in solving this problem. If I can not retrieve my elephants, I might lose my job. That’s why I ask for help from all of you.

   Reply ↓
4. ricardo September 20, 2018 at 9:34 pm

   meus amigos estou numa sinuca de bico, é isso mesmo, meus arquivos estão tds criptografados .krab e tenho um studio com trabalhos de clientes diversos e não consigo acessar mais nada e estou aqui a ponto de enlouquecer pq já procurei em tds os locais que era possivel na internet e não existe uma forma de resolver isso, se estiver alguém que possa me ajudar ficarei muito agradecido com isso,
   se aguém puder ajudar agradeço desde já…

   [SensorsTechForum: comment has been edited, personal information was removed from it]

   Reply ↓

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