GandCrab Ransomware - How to Remove It
THREAT REMOVAL

GandCrab Ransomware Virus – How to Remove It

This article is made in order to best explain what is the GandCrab Ransomware infection, what are it’s versions and how to make sure and remove this ransomware virus effectively from your computer.

GandCrab ransomware is a cryptovirus for Windows machines, which aims to encrypt the files on the computers that are infected by it and then demands a ransom to be paid either in the cryptocurrency DASH or the BitCoin currency. The ransomware has been active since January 2018 and It has changed it’s versions a lot since it first started infecting computers, using new encryption algorithms, like Salsa20 and TEA(Tiny Encryption Algorithm). GandCrab ransomware has reached the point where security experts call it “The New King of Ransomware”, since the virus has been infecting users on a global scale. If your computer has been infected by GandCrab ransomware or you want to learn more about it and how you can tackle this virus, we suggest that you read this article. It contains all information available on the GandCrab ransomware and we keep it updated, since the virus is also constantly updated too.

Threat Summary

NameGandCrab
TypeRansomware
Short DescriptionGandCrab ransomware encrypts your files and you cannot open them, unless you pay a lot of cryptocurrency money to the cyber-criminals. The ransom is paid in Dash or BitCoin currencies.
SymptomsGandCrab ransomware renders the files on your computer unopenable and changes the wallaper to it’s version name. Sets an extension based on it’s variant.
Distribution MethodSpam Emails, Email Attachments, Executable files, .JS Files, Malicious Macros
Detection Tool See If Your System Has Been Affected by GandCrab

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Malware Removal Tool

User ExperienceJoin Our Forum to Discuss GandCrab.
Data Recovery ToolWindows 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 Ransomware – Update February 2019

Update! February 2019 brings good news as malware researchers from BitDefender have released a new version for their GandCrab Decryption tool, which is available from the link leading to the BitDefender GandCrab 5.1 Decryptor.

GandCrab Ransomware – How Does It Infect

For the GandCrab ransomware to be spread, the virus uses different forms of replication and infection methods. Below, we have summarised each method and we show you more about them.

Method 1: Via e-mail.

This is the most commonly used method to infect a computer with GandCrab ransomware. The virus’s infection file may be of various

What are the files which viruses are mostly using to infect your computer? What are the file types which are part of the viruses' payload after they infect?
file types and these file types may be uploaded in e-mails where they may pretend to be legitimate documents. Below you can see an example of such case, taking advantage of a .JS (JavaScript) file that pretends to be an image:

2019/01.28 10:40
Giovanni Price [email protected]
Attachment: PIC0101302924102-jpg.zip (69 KB)
E-mail Body: ;)

When the user opens the e-mail, he or she will see the file contained in an archive. When this infection file is extracted and ran, it causes the infection with GandCrab ransomware:

Another method used by GandCrab is to make it as if the JavaScript file is an actual document and this file may be contained in a .7z archive that automatically extracts and executes the virus when you open it – clever indeed.

But .JS files are not the only way of spreading GandCrab ransomware, since the malware authors have also used malicious Microsoft Office documents as well as Adobe .PDF files to infect victims. The way they use them is by disguising the actual document’s malicious nature with obuscators and infecting it with malicious Macros. These macros are basically a code that is triggered each time when you click on “Enable Content” or “Enable Editing” in a document and once this is done, infection with GandCrab is inevitable. Below, you can see how such an attack can occur over e-mail:

Method 2: Via Malicious Files Uploaded on Sites

This method is also very commonly used and we have seen GandCrab developers to use it before. As Fortinet researchers have already reported, they have detected multiple compromised WordPress websites that contained GandCrab ransoware’s infection file directly uploaded on websites that offer software cracks for the following programs:

  • Crack SysTools PST Merge 3.3
  • Crack Securitask 2005 1.40H
  • Crack Merging Image to PDF 2.8.0.4
  • Crack for Windows Password Key Enterprise 9.6.2.

Thanks to Fortinet researchers, you can see some of the screenshots of these virus sites below:

Besides cracks, other infection files may also be uploaded with new versions that are likely to appear in the future too, like fake setups, portable versions of programs, freeware app installers and many other seeming legitimate programs, that turn out to be malicious.

GandCrab Ransomware – Background and Activity

GandCrab ransomware is a very persistent threat, which has evolved with many new versions over the years. To summarise these versions, we will pay attention to the most significant changes for each version. This will better help you understand what kind of virus you are dealing with.

GandCrab Ransomware – Variants

The GandCrab ransomware has been identified in a new attack campaign carrying the .GDCB extension, learn about it our removal guide
GandCrab v1 (.GDCB)

The first version which we can call GandCrab appeared back in January, 2018. Security experts at Comodo have established that the virus encrypted victims’ files and generated a unique decryption key. The GandCrab v1 was the first ransomware to ever use DASH in a cyber-extortion scheme. The GandCrab ransomware v1 used to copy it’s malicious files in the %AppData%\Microsoft directory and then inject malicious code in the a system process, called nslookup.exe. The virus used to communicate to pv4bot.whatismyipaddress.com in order to see what is the IP on the infected PC and then run the nslookup service to connect to gandcrab.bit.a.dnspod.com, using the .bit domain. The version spread rapidly, but it did not last long. Researchers were able to devise a decryptor for the virus and shortly after that, the crooks stopped spreading the infection files.

What is .CRAB ransomware virus? How to remove GandCrab v2 ransomware infection? How to restore .CRAB encrypted files without paying the ransom?
GandCrab v2 (.CRAB)

This variant quickly came out a week after the researchers were able to decrypt the first version. It used the .CRAB extension which it added to the files, that the virus encrypted by using a brand new encryption algorithm. To spread it, researchers used spam e-mails and after an infection was done, the domains for communications used were hardcoded to ransomware.bit and zonealarm.bit.

The GandCrab 3 virus has been identified in an attack encrypting the victim files with the .CRAB extension, read more in our removal guide
GandCrab v3

The cyber-criminals behind GandCrab did not stop evolving and in April they have started infection campaigns featuring new version of the virus, a v3. The GandCrab v3 iteration aimed to make sure that the victims know it’s there by changing the desktop wallpaper on the compromised computers to it’s ransom note. The virus also aimed to introduce fear in victims by having scripts that were added in the RunOnce key:

→HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\whtsxydcvmtC:\Documents and Settings\Administrator\Application Data\Microsoft\yrtbsc.exe

These scrips aimed to switch between the wallpaper and the ransom note text file of the virus automatically in order to pressure victims into paying the ransom.

What is .KRAB files virus? It is a new version of GANDCRAB ransomware. How to remove .KRAB files virus and restore encrypted files without buying a decryptor?
GandCrab v4

The 4th version of GandCrab ransomware was made to perform quite the activities and besides the new .KRAB extension used by it, it also added a lot of new updates and changes to it. As researchers at Comodo have found out, GandCrab v4 used the Tiny Encryption Algorithm, also known in the trade as TEA in order to avoid being detected by the cyber-criminals. The name of this cypher suggests that it is used to be very fast in encrypting files affter infection.

Besides a newly-made wallpaper, the crooks, behind GandCrab ransomware now have started using new methods to spread the virus – software cracks. As we mentioned in the “distribution” section above, the crooks uploaded cracks and once the victims downloaded and ran them, the ransomware is dropped on the PC. One malicious file was detected to pose as Crack_Merging_Image_to_PDF.exe. The virus also had added new features, like the ability to create a custom URL for it’s Tor payment page based on the unique ID of the infected computer. The virus also used to relay data from the infected machine to it’s Command and Control server and this data is also XOR encrypted for a secure communication. Not only this, but researchers believe that the virus was likely made in Russia, since it used a very specific key string, called “jopochlen”, which is a combination of two russian words.

The ransom note of GandCrab ransomware i was called KRAB-DECRYPT.txt and the virus checks for multiple Windows files and system folders which it skips encrypting If they are created in the victim machine, like it’s ransom note. GandCrab v4 did not change the file names of the encrypted files. This was the first time, where the payment page of GandCrab started appearing with an updated and new design:

Other interesting changes of the virus were that it started targeting users of older Windows OS’s, like Windows XP as well:

Related:
The notorious GandCrab ransomware has received a major update, targeting Windows XP as well as older Windows server versions, for which updates are stopped.
GandCrab Ransomware Updated – Targets Windows XP and Older Servers

How to remove GANDCRAB V5.0 ransomware and restore data? What is GANDCRAB V5.0 ransomware? A crypto virus that corrupts valuable files and demands a ransom
GandCrab v5

The 5th version of GandCrab is the most significant one and is still being used today. The ransomware virus has updated it’s wallpaper and in all of it’s v5 variants it uses random file extensions with scrambled letters. This is the most significantly changed version of the virus, since it ditched the previous encryption algorithms used by it and added the Salsa20 encryption mode. Not only this, but the cyber-criminals have also managed to find out that the ransom page of the virus was also changed to the following:

The main text file with the ransom note was also changed and is currently looking like the following:

—= GANDCRAB V5 =—

UNDER NO CIRCUMSTANCES DO NOT DELETE THIS FILE, UNTIL ALL YOUR DATA IS RECOVERED
FAILING TO DO SO WIL RESULT IN YOUR SYSTEM CORRUPTION, IF THERE ARE DECRYPTION ERRORS

Attention!

All your files, documents, photos, databases and other important files are encrypted and have the extension:

The only method of recovering files is to purchase an unique private key. Only we can give you this key and only 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 http://gandcrabmfe6mnef.onion/ b6314679c4ba3647/
| 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

The wallpaper of the 5.0 versions was also changed having the version, the ransom note and the extensions added to it in a red screen:

gandcrab v5 desktop ransom wallpaper sensorstechforum

The main ransom note in the wallpaper of the virus started looking like the following:

ENCRYPTED BY GANDCRAB 5.0
DEAR
YOUR FILES ARE UNDER STRONG PROTECTION BY OUR SOFTWARE IN ORDER TO RESTORE IT YOU MUST BUY DECRYPTIOR
For further steps read [extension letters].DECRYPT.html that is located in every encrypted folder.

GandCrab Ransomware – Encryption Process

The encryption of GandCrab ransomware has changed quite a bit over the years, and a lot of it’s versions have so far been decrypted:

Related:
How to decrypt files, encrypted by GandCrab ransomware for free, using the BitDefender GandCrab Decryptor? Instructions for GANDCRAB v1, v2, v3, v4 and v5.
How to Decrypt Files Encrypted by GandCrab Ransomware (Free)

However, the newer v5 variants of the virus are still undetectable and researchers are still trying to make progress towards decoding files.

The encryption routing of this virus begins with the Salsa20 encryption mode which is strong and fast and is made in such way to avoid detection. The virus aims to encrypt absolutely all usable file types in Windows, besides the ones on it’s White list. Before starting the actual encryption, GandCrab ransomware checks your computer for the following data:

  • Username.
  • Name of the computer.
  • Group the computer belongs to.
  • If an antivirus is installed.
  • It’s language.
  • It’s keyboard languages.
  • Operating system information.
  • Hard Drive Information.
  • IP address.

The virus then relays the gathered information to it’s command and control server via encrypted communication modes. Then, the ransomware proceeds to encrypt all of the files on the victimized PC, where it excludes the following files and folders:

Files:
It’s ransom note {Extension}-DECRYPT.txt
Desktop.ini
Autorun.inf
Ntuser.dat
Iconcahce.db
Bootsect.bak
Boot.ini
Ntuser.dat.log
Thumbs.db
Ntl dr
NTDETECT.COM
Bootfont.bin
Folders:
\ProgramData\
\IETldcache\
\Boot\
\Program Files\
\Tor Browser\
\All Users\
\Local Settings\
\Windows\

After encryption has been completed, depending on the version it is in, GandCrab ransomware may self-delete it’s files.

Remove GandCrab Ransomware and Try to Restore Encrypted Files

We have always believed that GandCrab and Cerber ransomware were made by the same people, which means that this virus is a very advanced and persistent threat, that will likely keep terroizing computers either via this name or another one.

Either way, to remove GandCrab ransomware, you are welcome to use the manual removal methods (first two removal steps) below in combination with the information we have added in this article or you can remove GandCrab ransomware automatically by scanning your computer with an advanced anti-malware program, which is what most security experts would advise doing.

If you want to try and restore files, you may have figured out by now that the encryption used by GandCrab is quite difficult to break if your variant is not among the decryptable ones. In this case we would advise that you try using the alternative file recovery methods we have provided below in the “try to restore” step. They may not be a 100% guarantee solution for file recovery, but with their aid, you might be able to get at least some files back to normal. Last but not least, we would strongly recommend that you do a backup of GandCrab’s ransom note and encrypted files as well, because such viruses are dangerous and may break your files beyond decryption if you try to tamper with them directly.

Ventsislav Krastev

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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