GandCrab ransomware - How to remove

GandCrab crypto-virus is one of the newest ransomware infections and security researchers indicate it as a curious case. This malware has some intriguing features that had never been detected in viruses of this category. A campaign called Seamless is a malvertising chain, pushing the RIG exploit kit and frequently delivering Ramnit Trojan. Alcatraz ransomware was also distributed in this manner.

However, now this campaign is taking GandCrab virus under its wing. The ransomware uses both AES and RSA encryption and appends .GDCB extension to the damaged digital files.

What is special about the GandCrab ransomware

The GandCrab crypto-virus will add a GDCB-DECRYPT.txt file into victims’ computers. The executable file will introduce the first instructions that the hackers are giving. Victims are required to download the TOR browser which allows surfers to access websites that would not be reachable with a normal browser. This program opens doors to dark and deep web but we hope that you won’t embark on the journey through them (The Dangers Of Exploring The Dark Web – Stay Away! Be Safe!).

As soon as people enter the required page via TOR (gdcbghvjyqy7jclk.onion). The launched site will display information about the infected computer: location according to IP address, operating system, PC user, set language and etc. Victims can actually upload 1 encrypted file into the page and decrypt it. The digital file should not be bigger than 2 MB and has to be any of these types: txt, jpg/jpeg, bmp, png, gif. For recovery of all files, hackers are requiring victims to pay 1.5 DASH. In the TOR website, it is explained to equal $1200. At the time of writing this article, the actual worth of 1 DASH was $1135.11.

GandCrab virus can have several payloads. During investigation, we noticed these malicious files: 4.exe and 2018-01-29_00-38-31.exe. According to the copyright on these files, they were generated by an unknown source called “kdabjnrg”.

Another interesting detail about this GandCrab crypto-malware is that it accepts an open source, peer-to-peer DASH cryptocurrency. We have never seen ransomware authors require fees in this digital form before. However, this is not that surprising has Bitcoin has been replaced by Monero in a couple of viruses we discussed before.

Versions of GandCrab ransomware

Variant name	Release date	Extension	Contact	Decryptor
GandCrab (Original)	Jan 26, 2018	.CRAB .GDCB	gdcbghvjyqy7jclk.onion/(yourID)	YES
GandCrab v2	Mar 5, 2018	.CRAB .GDCB	gdcbmuveqjsli57x.onion/(yourID)	NO
GandCrab v3	Apr 28, 2018	.CRAB	http://gandcrab2pie73et.onion/(yourID)	NO
GandCrab v4	June 30, 2018	.KRAB	gandcrabmfe6mnef.onion/(yourID)	YES. Also has a prevention
GandCrab v5	Sept 24, 2018	.[5-random-unique-letters]	gandcrabmfe6mnef.onion/(yourID)	YES. Also has a Vaccine

.KRAB extension ransomware (Gandcrab v4)

GandCrab ransomware compared to others has evolved very rapidly with 4 new variants (and their other adjusted versions) in only 6 months, making it one of the most widespread ransomware around. While the principle stayed the same and GandCrab was still encrypting files and asking for a ransom, the technical and some other features have been altered significantly, to make it more notorious and persistent.

The first noticeable modification that GanCrab v4 has is the famous extension that now is spelled .KRAB, as well as a matching ransom note ‘KRAB-DECRYPT.txt’ and the new Thor link for payment and information. Furthermore, now hackers decided to use Salsa20 algorithm to encrypt the files instead of the usual RSA and AES. According to some cyber enthusiasts now GandCrab 4 is spreading via fake program cracking sites and download option, placed on legitimate web pages or fraud blogs and asks for US1200 dollars in DASH cryptocurrency (around 4.7DSH).

Since GandCrab demonstrate sophisticated encryption and spreading methods with each variant, it became hard for cybersecurity professionals to keep up trying to decrypt the files, therefore, South Korean security company AhnLab released a preventative injection for GandCrab v 4.1.2, which helps to avoid GandCrab virus encryption, but only the 4.1.2 version. This app creates a special ‘hexidecimal string number .locked’ file in
C:\ProgramData folder that replicates the one from GandCrab which is the indicator that the computer has already been compromised, so that virus would not lock data twice, making it inaccessible even when the victim pays. Of course, the crooks will soon find a way/release new variant and overcome this obstacle.

How to decrypt GandCrab virus locked files

At the time of writing this article, security researchers have not introduced a guaranteed way of recovering the encrypted files. Since this GandCrab crypto-virus appears to be distributed rather actively, we are sure that specialists are trying to find a way of creating a free file-decryptor. Until then, we hope that you won’t decide to send 1.5 DASH to hackers. Do not be frightened by the message, stating that you only have 5-4 days to pay the ransom.

On the other hand, there might be a way of decrypting files manually. Please check whether Shadow Volume Copies are left untouched. Additionally, some third-party file-recovery tools could also be of an excellent assistance to victims of ransomware. However, before any of these recovery attempts, you have to get rid of the crypto-malware.

UPDATE: on October 25th, 2018, Bitdefender together with Europol and Romanian Police released a GandCrab decryption tool for the first, fourth and fifth versions. It is an update of a previous Bitdefender’s Decryptor released back in March. You can find the newest decrypter of Gandcrab v1, v4 and v5 versions here on NoMoreRansom.org project. Simply install the program and follow the instructions. Thanks to this new development, users no longer need to consider paying the ransom if they want to retrieve their files. All they have to do is download the new decryptor from BitDefender and restore their data free-of-charge.

As well as this, there is a special decryptor for GandCrab victims from Syria, which works on all versions and can be found Here. However, it works only for users that are from Syria.

How does ransomware like GandCrab spread

Well, this particular example is distributed during the Seamless campaign, forcefully shoving RIG exploit kits. This is a common strategy for the delivery of ransomware infections. On the other hand, viruses could enter thru poorly-protected RDPs, or might be installed from a malicious online ads/website. In order to keep the operating system free of any vulnerabilities, we suggest you to regularly update all of your software and OS.

In order to protect yourself from malware infections, you have to be very careful during browsing. Do not click on random content. Do not download software from unknown or illegal sources. If you find this battle against hackers too difficult, we offer some help. Install Spyhunter and experiment with their amazing features. These programs will be able to detect any malware parasite and keep devices well-protected.

Automatic Malware removal tools

How to recover GandCrab ransomware encrypted files and remove the virus

Step 1. Restore system into last known good state using system restore

1. Reboot your computer to Safe Mode with Command Prompt:

for Windows 7 / Vista/ XP

• Start → Shutdown → Restart → OK.
• Press F8 key repeatedly until Advanced Boot Options window appears.
• Choose Safe Mode with Command Prompt.

for Windows 8 / 10

• Press Power at Windows login screen. Then press and hold Shift key and click Restart.
• Choose Troubleshoot → Advanced Options → Startup Settings and click Restart.
• When it loads, select Enable Safe Mode with Command Prompt from the list of Startup Settings.

 

2.Restore System files and settings.

• When Command Prompt mode loads, enter cd restore and press Enter.
• Then enter rstrui.exe and press Enter again.
• Click “Next” in the windows that appeared.
• Select one of the Restore Points that are available before GandCrab v2 has infiltrated to your system and then click “Next”.
• To start System restore click “Yes”.

 

Step 2. Complete removal of GandCrab v3

After restoring your system, it is recommended to scan your computer with an anti-malware program, like Spyhunter and remove all malicious files related to GandCrab v4. You can check other tools here.  

Step 3. Restore GandCrab ransomware affected files using Shadow Volume Copies

If you do not use System Restore option on your operating system, there is a chance to use shadow copy snapshots. They store copies of your files that point of time when the system restore snapshot was created. Usually GandCrab v2 tries to delete all possible Shadow Volume Copies, so this methods may not work on all computers. However, it may fail to do so. Shadow Volume Copies are only available with Windows XP Service Pack 2, Windows Vista, Windows 7, and Windows 8. There are two ways to retrieve your files via Shadow Volume Copy. You can do it using native Windows Previous Versions or via Shadow Explorer. a) Native Windows Previous Versions Right-click on an encrypted file and select Properties → Previous versions tab. Now you will see all available copies of that particular file and the time when it was stored in a Shadow Volume Copy. Choose the version of the file you want to retrieve and click Copy if you want to save it to some directory of your own, or Restore if you want to replace existing, encrypted file. If you want to see the content of file first, just click Open.

b) Shadow Explorer It is a program that can be found online for free. You can download either a full or a portable version of Shadow Explorer. Open the program. On the left top corner select the drive where the file you are looking for is a stored. You will see all folders on that drive. To retrieve a whole folder, right-click on it and select “Export”. Then choose where you want it to be stored.

Step 4. Use Data Recovery programs to recover GandCrab v3 encrypted files

There are several data recovery programs that might recover encrypted files as well. This does not work in all cases but you can try this:

• We suggest using another PC and connect the infected hard drive as slave. It is still possible to do this on infected PC though.
• Download a data recovery program.
• Install and scan for recently deleted files.

Note: In many cases it is impossible to restore data files affected by modern ransomware. Thus I recommend using decent cloud backup software as precaution. We recommend checking out Carbonite, BackBlaze, CrashPlan or Mozy Home.