GOG ransomware - How to remove

We always try to prep our visitors for the unexpected content that might be introduced to them via websites they choose to visit everyday. GOG crypto-ransomware is a yet another threat in the cyber world, dedicated to encryption of files. It uses a complicated cryptography to reassure that affected files would no longer run and victims would be forced to seriously consider paying the demanded fee for decryption tool/code. GOG virus is a variant that does not differ from its ancestors. In fact, the creators of this sample decided to go with a very popular .LOCKED extension which evidently shows which files are ruined by RSA encryption. According to the research that focused on GOG virus, an exact cipher was discovered: RSA-4096. This basically means that the virus generates two keys: a public and a private one. As you may guess, only the private key which is used for decryption is hidden from the victims. Without the private key, restoration of files is nearly impossible. However, security researchers are known to discover cures for ransomware infections even without directly receiving a public key. GOG virus is not an extraordinary infection and we sure hope that analysts will discover a solution.

GOG ransomware: how does it proceed?

GOG ransomware chose a quite typical way of proceeding in the infected device. Firstly, to successfully run in the background without users’ knowledge, the payload of this infection has to initiate changes that is the backbone of a ransomware success. Without getting automatically launched with every restart of the device, GOG virus would not be capable of running a scan to find files nor it would be able to begin encryption with an RSA cipher. For this purpose, ransomware makes modifications to Windows Registry Keys, mostly inserting entries that would help the payload of GOG virus to run in the background without getting detected.

A very common extension has been selected by this sample: it marks data with .LOCKED extension. It will be added after the original extension which indicates the type of the file. Unfortunately, it is complicated to create free decryptors: security analysts have to spend some time examining an infection. RSA-4096 cipher is a powerful tool to make file encryption permanent. Nevertheless, there had been a number of times when security researchers still managed to generate file-decrypting software apps. Furthermore, GOG virus is going to insert a text file in the victims’ computer, giving explicit instructions. To examine the content of DecryptFile.txt file you can look above. In addition to that, the creators of this ransomware directs people to some websites. A screenshot of it can be seen below. According to the website, people are going to be demanded 0.3 BTC (about 294.06 US dollars). You can also notice that the Bitcoin address for transactions is also indicated. If a victim fails to send the money, crooks threaten to delete the decryption key. If the hackers get impatient, they might double the price for a decryption software.

Decryption of files that were selected by GOG ransomware

For now, we can not give you a great news, concerning the decryption of GOG virus. Security researchers are probably going to require some patience from victims since generation of free decryptors is not a simple task. While you are waiting, you can check whether this ransomware deletes Shadow Volume copies. If not, it would be possible to restore files. Additionally, there is a number of free decryptors already: maybe one of them is going to work on your files. If you are not infected, but you store a lot of valuable information in your device, we advise you to back this data up. You can do this by uploading files into online storage facilities or simply making copies of files and importing them into an USB flash drive.

GOG ransomware: how does it infect devices?

An infection with ransomware virus will not appear completely out of nowhere: a victim has to download the payload. A source for such threat might be your email account, misleading downloads or drive-by download. One of the most popular ways to spread ransomware is to send the payload as an attachment to a fabricated email letter. You might receive such correspondence completely out of the blue. Most frequently, infectious email letters are formed as extremely urgent. In reality, they are simply fake. The lesson here is to never open letters that seem to be quite out of the ordinary. In addition, do not download software from unreliable locations since you might actually download a Trojan.

Spyhunter or Malwarebytes will deal with GOG ransomware virus. It won’t stand a chance against such sophisticated anti-malware programs. More information, concerning manual removal and decryption, can be found below.

How to recover GOG 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 GOG ransomware has infiltrated to your system and then click “Next”.
• To start System restore click “Yes”.

 

Step 2. Complete removal of GOG ransomware

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 GOG ransomware. You can check other tools here.  

Step 3. Restore GOG 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 GOG ransomware 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 GOG ransomware 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.