This article has been made with the goal of explain what is the updated GandCrab v4.1 ransomware version and how to remove it from your computer plus how you can restore files, encrypted with the .krab file extensions.
An updated version of the recently released version 4 of the GandCrab ransomware menace has been detected by security researchers. The ransomware encrypts the files, adding the .krab file extension with small letters unlike it’s previous v4 variant which used capital letters of the same suffix. The ransomware still uses the very same strong encryption algorithm and after encoding the files, the virus ads the krab-decrypt.txt ransom note to the encoded files. What is particularly interesting about the malicious file of this ransomware is that it uses an .exe file for it’s infection to take place. More information, removal and recovery of files, encrypted by this GandCrab v4.1 version is available in our research article underneath.
Threat Summary
| Name | GandCrab v4.1 |
| Type | Ransomware, Cryptovirus |
| Short Description | 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 V4.1 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 malware
Download
Malware Removal Tool
|
User Experience | Join Our Forum to Discuss GandCrab v4.1. |
| 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 – Update October 2018 – Free Decryption is Now Available
Researchers have successfully made a breakthrough with GandCrab ransomware and have developed a decryption tool for all versions of GandCrab ransomware. Following these developments, we have published instructions on how to decrypt GandCrab encrypted files for free, which you can find in the related article below:
GandCrab v4.1 .krab Ransomware – Information Database:
GandCrab v4.1 (.krab) Ransomware – How Does It Infect
The main method of infection of the 4.1 version of GandCrab ransomware is reported by automated analyzer VMRay to be an .exe file, with the following main indicator of compromise (IOC):
8ecbfe6f52ae98b5c9e406459804c4ba7f110e71716ebf05015a3a99c995baa1 (SHA256)
Jeremy Witt’s Dental Records.exe
The file is similar to the executable which was detected in association with the v4 GandCrab variant where the .exe file posed as a fake crack for software, such as Image to PDF converters or other licensed versions of programs. These programs were uploaded on suspicious websites, which were with low reputation, but the as the name “Jeremy Witt’s Dental Records.exe” suggests, the file may be automatically generated on a fake dental records database website which the victim downloads, while believing, these are actually the dental records. Not only this, but the ransomware also still uses similar exploits, like SMB v1 and prays on users who lack the MS17-010 patch installed on their operating systems.
Furthermore, in addition to an .exe type of file, this malware may also be spread via other means as well, including spammed e-mail messages which may carry malicious e-mail attachments. The e-mails may contain deceptive messages in them that point out that the attachment is an important type of file, like an invoice, receipt or other form of document.
GandCrab V4.1 (.krab) Virus – Activity Report
Once the 4.1 version of GandCrab has infected your computer, the malware drops It’s malicious pyload on the victim’s computer with the following permissions:
- {random name}.lock with Access permissions.
- krab-decrypt.txt with Access and Write permissions
- A lot of randomly named .lock files with Access and Write permissions created in most commonly used folders.
Besides these files, the ransomware begins modifications in the %SystemDrive% directory as it attacks the following directories and tampers with the system files in them:
→ C:\bootmgr
C:\Program Data
C:\Recovery
C:\System Volume Information
C:\Users
C:\Documents
C:\AppData\Roaming\Microsoft\Templates\LiveContent\16\Managed\Document Themes\{random number}
In those directories, the GandCrab v4 ransomware goes through great extents to create a lot of .lcok types of files, that are likely related to the encryption folders that are targeted by the ransomware, since it goes through all of the sub-folders in those directories to create those .lock files. These files are believed to be related to the encryption process, more importantly to be the decryption keys themselves which are likely different for every folder.
The GandCrab v4.1 also heavily attacks the Windows Registry Editor where the ransomware creates multiple different registry value entries with Access, Read and Write permissions. The registry sub-keys which are attacked are the following:
→ HKEY_CURRENT_USER\Control Panel\International
HKEY_CURRENT_USER\Keyboard Layout\Preload
HKEY_CURRENT_USER\SOFTWARE\keys_data\data
HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Wbem\CIMOM
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Tcpip\Parameters
So far, by the looks of it, GandCrab v4.1 has been created by someone with extensive knowledge on how to remotely tamper with Windows machines.
The ransom note of GandCrab v4.1 is created on almost every folder where files are encrypted, so that it is hard to not see it. What is interesting is that the 7.86 kb ransom note file is also in the Recycle Bin which further shows the great extent to which the makers of this ransomware want you to know of it’s presence. The ransom note may still contain the very same GandCrab extortion message, this time starting with the 4.1 variant:
–= GANDCRAB V4.1 =—
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 a 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—
lAQAADcGuK2O86SjorV5S***2252_chars***3xoPSX/TrEnwTiQ76HdztGYuXZ4KO7rogc=
—END GANDCRAB KEY—
—BEGIN PC DATA—
wfKD6iudumBkmpL8IRr4U7***76_chars***mMngioqtOiJtTit2DjRIuBtNYA==
—END PC DATA—
The ransom note leads victims to GandCrab’s Tor web page, where they are demanded an even higher ransom payment in the DASH cryptocurrency ($1200), as researcher Kevin Beaumont on DoublePulsar reports:
Source: DoublePulsar.com
For the moment, it is not clear whether or not GandCrab v4.1 deletes the shadow copies, but it is very likely that the virus uses the following commands to erase them:
→ 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
GandCrab v4.1 – Encryption Report
The encryption which Is used by this variant of GandCrab ransomware is quite different from the standard RSA+AES RC4 encryption mode. The virus now uses the Salsa20 encryption mode, developed by Daniel J.Bernstein and released back in 2007. With key sizes of 256 bits, this encryption contains a combination of XOR and ARX operations. This makes the ciphers with the advantage of giving crooks the benefit of locking the files so that they may not be easily decryptable, even by professionals.
The virus looks for different types of important files, with a priority of hunting for database files of Microsoft Access and Microsoft Outlook files as well. The ransomware also goes through great extents to prevent important Windows files from being encrypted so that you can still use your PC to pay the ransom online in the cryptocurrency DASH. The encrypted files by GandCrab v4.1 are appended the .krab file extension after their original one and they start to appear like the following:
How to Remove GandCrab V4.1 Ransomware and Try to Restore .krab Files
GandCrab v4.1 ransomware is not one of those threats that you should underestimate if you want to remove it. For maximum effectiveness of the removal process of this ransomware, it is strongly recommended that you follow either the manual or automatic removal process underneath. But be careful and follow the manual removal only if you have some malware removal experience. Other than that, as security experts often advise, it is recommended that you download an advanced anti-malware program which will take care of the removal of GandCrab v4.1 for you automatically plus ensure that your PC remains protected in the future as well.
Be advised that if you want to try and restore your encrypted files, we have prepared some theoretical alternatives below in step “2. Restore files, encrypted by GandCrab v4.1” underneath. They may not work at a 100% effectiveness but might be able to help you recover at least some of your encrypted files, which is still better than paying ransom to cyber-criminals.
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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Attention! SensorsTechForum strongly recommends that all malware victims should look for assistance only by reputable sources. Many guides out there claim to offer free recovery and decryption for files encrypted by ransomware viruses. Be advised that some of them may only be after your money.
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.
- Profile of the content creator.
- Make sure that real people are behind the site and not fake names and profiles.
- Verify Facebook, LinkedIn and Twitter personal profiles.
How to Remove GandCrab v4.1 from Windows.
Step 1: Boot Your PC In Safe Mode to isolate and remove GandCrab v4.1
Step 2: Uninstall GandCrab v4.1 and related software 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 uninstall most programs.
Step 3: Clean any registries, created by GandCrab v4.1 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 GandCrab v4.1 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: Scan for GandCrab v4.1 with SpyHunter Anti-Malware Tool
Step 5 (Optional): Try to Restore Files Encrypted by GandCrab v4.1.
Ransomware infections and GandCrab v4.1 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 top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.
Get rid of GandCrab v4.1 from Mac OS X.
Step 1: Uninstall GandCrab v4.1 and remove related files and objects
1. Hit the ⇧+⌘+U keys to open Utilities. Another way is to click on “Go” and then click “Utilities”, like the image below shows:
- Go to Finder.
- In the search bar type the name of the app that you want to remove.
- Above the search bar change the two drop down menus to “System Files” and “Are Included” so that you can see all of the files associated with the application you want to remove. Bear in mind that some of the files may not be related to the app so be very careful which files you delete.
- If all of the files are related, hold the ⌘+A buttons to select them and then drive them to “Trash”.
In case you cannot remove GandCrab v4.1 via Step 1 above:
In case you cannot find the virus files and objects in your Applications or other places we have shown above, you can manually look for them in the Libraries of your Mac. But before doing this, please read the disclaimer below:
You can repeat the same procedure with the following other Library directories:
→ ~/Library/LaunchAgents
/Library/LaunchDaemons
Tip: ~ is there on purpose, because it leads to more LaunchAgents.
Step 3 (Optional): Try to Restore Files Encrypted by GandCrab v4.1.
Ransomware infections and GandCrab v4.1 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 top, choose Data Recovery - Data Recovery Wizard for Windows or Mac (depending on your OS), and then download and run the tool.
GandCrab v4.1 FAQ
What is GandCrab v4.1 ransomware and how does it work?
GandCrab v4.1 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 algorithm how 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.
How does GandCrab v4.1 ransomware infect my computer?
Via several ways.GandCrab v4.1 Ransomware infects computers by being sent via phishing e-mails, 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.
After you download and execute this attachment, a drive-by download occurs and your computer is infected with the ransomware virus.
Another way, you may become a victim of GandCrab v4.1 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 .GandCrab v4.1 files?
You can't. At this point the .GandCrab v4.1 files are encrypted. You can only open them once they are decrypted.
Decryptor did not decrypt my data. What now?
Do not panic and backup the files. If a decryptor did not decrypt your .GandCrab v4.1 files successfully, then do not despair, because this virus is still new.
One way to restore files, encrypted by GandCrab v4.1 ransomware is to use a decryptor for it. But since it's a new virus, advised that the decryption keys for it may not be out yet and available to the public. We will update this article and keep you posted as soon as this decryptor is released.
How Do I restore ".GandCrab v4.1" files (Other Methods)?
Yes, sometimes files can be restored. We have suggested several file recovery methods that could work if you want to restore .GandCrab v4.1 files.
These methods are in no way 100% guarantee that you will be able to get your files back. But if you have a backup, your chances of success are much greater.
How do I get rid of GandCrab v4.1 ransomware virus?
The safest way and the most efficient one for the removal of this ransomware infection is the use a professional anti malware software. It will scan for and locate GandCrab v4.1 ransomware and then remove it without causing any additional harm to your important .GandCrab v4.1 files.
Also, keep in mind that viruses like GandCrab v4.1 ransomware also install Trojans and keyloggers that can steal your passwords and accounts. Scanning your computer with an anti-malware software will make sure that all of these virus components are removed and your computer is protected in the future.
What to Do If nothing works?
There is still a lot you can do. If none of the above methods seem to work for you, then try these methods:
- Try to find a safe computer from where you can can login on your own line accounts like One Drive, iDrive, Google Drive and so on.
- Try to contact your friends, relatives and other people so that they can check if they have some of your important photos or documents just in case you sent them.
- Also, check if some of the files that were encrypted it can be re-downloaded from the web.
- Another clever way to get back some of your files is to find another old computer, a flash drive or even a CD or a DVD where you may have saved your older documents. You might be surprised what will turn up.
- You can also go to your email account to check if you can send any attachments to other people. Usually what is sent the email is saved on your account and you can re-download it. But most importantly, make sure that this is done from a safe computer and make sure to remove the virus first.
More tips you can find on our forums, where you can also asks any questions about your ransomware problem.
