Home Guides GandCrab 2.1 ransomware: removal and decryption

GandCrab 2.1 ransomware: removal and decryption

5 min read
The well-orchestrated GandCrab ransomware campaign has coined version 2.1, which boasts more sophisticated distribution and still uses the .CRAB file extension.

GandCrab v2.1 is currently one of the dominating and most competently coded ransomware threats at large. This strain isn’t a stationary target and has been through quite a bit of change over the past several months. The police takedown of its first edition’s Command and Control infrastructure was a slap for the crooks behind it but didn’t turn out a game changer. In less than a week, they contrived and started spreading an overhauled variant, and now in April 2018 a yet more dangerous build is wreaking havoc across the globe. As before, iteration 2.1 subjoins the .CRAB extension to encoded files and leaves a ransom note named CRAB-DECRYPT.txt. Cryptography-wise, the pest is just as professionally cooked up as the precursors and cannot be cracked without the RSA private key.

Ransomed files stained with the .CRAB extension
Ransomed files stained with the .CRAB extension

One of the most notable alterations in GandCrab 2.1 is the way it is propagating. The new trend is the use of an exploit kit codenamed Magnitude EK. Its malicious repertoire used to be isolated to pushing the Magniber ransomware, a possible successor of the ill-famed Cerber infection. It is unclear whether the GandCrab crew and those behind Magniber are the same people, or the former got in cahoots with the latter recently, but the fact persists that the perpetrating program under scrutiny has become harder to detect. A distinguishing trait of the present rotation wave is the use of a fileless infection technique to drop the malware payload. This makes the culprit sneakier and helps it fly below the radar of some antivirus tools.

GandCrab 2.1 still drops CRAB-DECRYPT.txt ransom note
GandCrab 2.1 still drops CRAB-DECRYPT.txt ransom note

When GandCrab 2.1 ends up inside a host environment, it goes a well-trodden route. First, it scours the hard disk and mapped drives for data that the victim is most likely to deem important. Just like the average ransomware out there, it goes with a list of common file extensions to look for. Then, it reaches out to one of its C2 servers and obtains the RSA public key that’s leveraged to encrypt the victim’s data. Meanwhile, the secret (private) key remains in the cybercriminals’ possession and never touches the contaminated system. Aside from the cipher-backed impact, the ransomware also modifies filenames by appending the .CRAB extension to them.

GandCrab 2.1 payment page
GandCrab 2.1 payment page

The ransom how-to manual named CRAB-DECRYPT.txt is intended to provide the steps for the user to get started on the recovery process. Specifically, it tells the victim to visit a specially crafted payment page using Tor browser. Alternatively, if this technology is locked in the user’s country of residence, they can use a regular browser and go to one of the indicated Tor2web gateways. Yet another new thing about GandCrab 2.1 is that the ransom note also lists an option to contact the attackers via the Jabber messenger. When on the above-mentioned payment page, the infected person gets information on the size of the ransom and the time left before the price doubles. Originally, the sum is $1,200 worth of Dash or Bitcoin. By the way, the previous variants of this blackmail Trojan demanded $400 in Dash, so the crooks’ appetite appears to be growing, plus they have added Bitcoin as a means of payment in version 2.1.

Although the felons offer test decryption of one file for free, that’s certainly cold comfort to the victims. Buying the decryptor at such a huge price is an awful solution, too. Under the circumstances, those contaminated should try all alternate recovery methods first. The sections below will shed light on how it’s done.

GandCrab 2.1 automated removal and data recovery

Owing to an up-to-date database of malware signatures and intelligent behavioral detection, the recommended software can quickly locate the infection, eradicate it and remediate all harmful changes. So go ahead and do the following:

1. Download and install the antimalware tool. Open the solution and have it check your PC for PUPs and other types of malicious software by clicking the Start Computer Scan button

Download .CRAB files virus remover

2. Rest assured the scan report will list all items that may harm your operating system. Select the detected entries and click Fix Threats to get the troubleshooting completed.

Data recovery toolkit to the rescue

Some strains of ransomware are known to delete the original files after the encryption routine has been completed. As hostile as this activity appears, it can play into your hands. There are applications designed to revive the information that was obliterated because of malfunctioning hardware or due to accidental removal. The tool called Data Recovery Pro by ParetoLogic features this type of capability therefore it can be applied in ransom attack scenarios to at least get the most important files back. So download and install the program, run a scan and let it do its job.

Download Data Recovery Pro

Data Recovery Pro

GandCrab 2.1 manual removal and file recovery

Some ransomware strains terminate themselves after completing the encryption job on a computer, but some don’t. Furthermore, the GandCrab 2.1 blackmail virus may prevent victims from using popular antimalware tools in order to stay on board for as long as possible. Under the circumstances, it may be necessary to utilize the Safe Mode with Networking or System Restore functionality.

Remove GandCrab v2.1 ransomware using Safe Mode with Networking

Remove GandCrab v2.1 ransomware using Safe Mode with Networking

Boot into Safe Mode with Networking. The method to do it depends on the version of the infected operating system. Follow the instructions below for your OS build.

  • Restart the machine. When the system begins loading back up, keep pressing the F8 key with short intervals. The Windows Advanced Options Menu (Advanced Boot Options) screen will appear.Boot into Safe Mode with Networking on Windows Vista and 7
  • Use arrow keys to select Safe Mode with Networking and hit Enter. Log on with the user account infected by the ransomware.
  • Click on the Search icon next to the Start menu button. Type msconfig in the search field and select the System Configuration option in the results. Go to the Boot tab in the upper part of the GUI.Boot options on Windows 8, 8.1 and 10
  • Under Boot options, select Safe boot and click the Apply button. A prompt will appear to reboot the computer so that the changes take effect. Select the Restart option and wait for the system to load into Safe Mode. Again, log on with the ransomware-stricken user account.

In Safe Mode, the ransom Trojan won’t keep security software from running or otherwise thwart troubleshooting. Open your preferred web browser, download and install an antimalware tool of choice and start a full system scan. Have all the detected ransomware components removed in a hassle-free way.

Get rid of GandCrab v2.1 ransomware using System Restore

Get rid of GandCrab v2.1 ransomware using System Restore

System Restore enables Windows users to roll back all changes made to the OS since the latest restore point creation time. This feature can help eliminate the most persistent ransomware. Before going this route, though, make sure System Restore had been enabled prior to the breach, otherwise the method will be inefficient.

  • Open Windows Advanced Options Menu as described in the previous section: hit F8 repeatedly when the PC is starting up. Use arrow keys to highlight the Safe Mode with Command Prompt entry. Hit Enter.Safe Mode with Command Prompt
  • In the Command Prompt window, type cd restore and hit Entercd restore command
  • Type rstrui.exe in the new command line and press EnterType rstrui.exe command
  • When the System Restore screen pops up, click Next, select a restore point that predates the contamination, and use the application’s controls to roll back the system to this earlier state.System Restore window

Be advised that even after the ransomware is removed, files will still be encrypted and inaccessible. The malicious code cleanup part, however, is important because it keeps a relapse of the infection from occurring further on and eliminates all opportunistic malware.

Ways of non-ransom recovery of .CRAB files

Cracking the crypto used by this ransom Trojan is more of a science fiction thing rather than an attainable prospect for the masses. This is why the troubleshooting in predicaments of this sort is a matter of two approaches: one is to pay the ransom, which isn’t an option for many victims; and the other is to apply instruments that take advantage of the ransomware’s possible weaknesses. If the latter is your pick, the advice below is a must-try.

Backups can make your day

Backups can make your day

Not only are you a lucky person in case you’ve been backing up your most important files, but you’re also a wise and prudent user. This isn’t necessarily a resource-heavy activity these days – in fact, some providers of online services are allocating a sufficient size of cloud storage space for free so that every customer can easily upload their critical data without paying a penny. Having removed the GandCrab 2.1 ransomware, therefore, all you have to do is download your stuff from the remote server or transfer it all from an external piece of hardware if that’s the case.

Restore previous versions of encrypted files

Restore previous versions of encrypted files

A positive upshot of using this technique depends on whether or not the ransomware has erased the Volume Shadow Copies of the files on your PC. This is a Windows feature that automatically makes and keeps the backups of data elements on the hard drive as long as System Restore is enabled. The cryptoware in question is programmed to switch off the Volume Shadow Copy Service (VSS), but it has reportedly failed to in some cases.

Checking one’s options regarding this workaround is doable in two ways: through the Properties menu of each file or by means of the remarkable open-source tool called Shadow Explorer. We recommend the software-based way because it’s automated, hence faster and easier. Just install the app and use its intuitive controls to get previous versions of the encrypted objects reinstated.
Shadow Explorer

Alternatively, you can leverage the Previous Versions feature, which is native to Windows operating system. This method is more cumbersome that the use of ShadowExplorer, but it can help restore the most important individual files on condition that the ransomware failed to disable the Volume Snapshot Service on the computer. Right-click on a file of choice and select Properties. Then, go to the Previous Versions tab as illustrated below.
Previous Versions

Go ahead and pick the file’s latest backup version on the list. Use the Copy or Restore buttons to reinstate this object to a new path or to its original folder, respectively.

Ransomware Prevention Tips

To avoid the GandCrab 2.1 ransomware and other file-encrypting infections in the future, follow several simple recommendations:

  • Toggle your email provider’s anti-spam settings to filter out all the potentially harmful incoming messages. Raising the bar beyond the default protection is an important countermeasure for ransom Trojans

  • Define specific file extension restrictions in your email system. Make sure that attachments with the following extensions are blacklisted: .js, .vbs, .docm, .hta, .exe, .cmd, .scr, and .bat. Also, treat ZIP archives in received messages with extreme caution

  • Rename the vssadmin.exe process so that ransomware is unable to obliterate all Shadow Volume Copies of your files in one shot

  • Keep your Firewall active at all times. It can prevent crypto ransomware from communicating with its C&C server. This way, the threat won’t be able to obtain cryptographic keys and lock your files

  • Back up your files regularly, at least the most important ones. This recommendation is self-explanatory. A ransomware attack isn’t an issue as long as you keep unaffected copies of your data in a safe place

  • Use an effective antimalware suite. There are security tools that identify ransomware-specific behavior and block the infection before it can do any harm.
These techniques are certainly not a cure-all, but they will add an extra layer of ransomware protection to your security setup.

Revise your security status

Post-factum assessment of the accuracy component in malware removal scenarios is a great habit that prevents the comeback of harmful code or replication of its unattended fractions. Make sure you are good to go by running an additional safety checkup.

Download GandCrab 2.1 ransomware removal tool

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