How to remove Unknown ransomware

Unknown ransomware can cause users to lose all their personal files if they do not have backups

The Phobos ransomware family includes Unknown ransomware, a dangerous file-locking malware. It encrypts users' personal files, such as photos, videos, and documents, using complex encryption algorithms. The primary goal of this virus is to steal money from victims in exchange for a decryption tool.

When it infiltrates the system, the affected files are appended with the .unknown extension, victim's ID, and masterfix@tuta.io email address. So if a file was previously named picture.jpg, after encryption it would look something like this – picture.jpg.id[4BTHC25J-7643].[masterfix@tuta.io].unknown. The thumbnails are changed into white pages as well.

The ransom note

Unknown ransomware creators drop two ransom notes on the affected machine – info.txt and info.hta. The former reads as follows:

All your files have been encrypted!
All your files have been encrypted due to a security problem with your PC. If you want to restore them, write us to the e-mail masterfix@tuta.io
Write this ID in the title of your message –
If you do not receive a response within 24 hours, please contact us by Telegram.org account: @Stop_24
You have to pay for decryption in Bitcoins. The price depends on how fast you write to us. After payment we will send you the tool that will decrypt all your files.
Free decryption as guarantee
Before paying you can send us up to 5 files for free decryption. The total size of files must be less than 4Mb (non archived), and files should not contain valuable information. (databases,backups, large excel sheets, etc.)
How to obtain Bitcoins
The easiest way to buy bitcoins is LocalBitcoins site. You have to register, click 'Buy bitcoins', and select the seller by payment method and price.
hxxps://localbitcoins.com/buy_bitcoins
Also you can find other places to buy Bitcoins and beginners guide here:
hxxp://www.coindesk.com/information/how-can-i-buy-bitcoins/
Attention!
Do not rename encrypted files.
Do not try to decrypt your data using third party software, it may cause permanent data loss.
Decryption of your files with the help of third parties may cause increased price (they add their fee to our) or you can become a victim of a scam.

This ransom note is a message from a cybercriminal who has gained unauthorized access to the recipient's computer and has encrypted their files, making them inaccessible to the user. The sender is demanding payment in the form of Bitcoins to restore access to the files and has provided instructions on how to purchase Bitcoins.

The sender has also offered a guarantee of free decryption for up to 5 files and has warned against attempting to decrypt the files using other methods. However, it is not a good idea to pay the ransom for several reasons:

1. There is no guarantee that the sender will actually restore access to the files, even after payment is made.
2. Paying the ransom encourages the attackers to continue their criminal activities and target other victims.
3. It is illegal to pay ransom in some countries and it could lead to legal consequences.
4. By paying the ransom, you may be funding criminal organizations or terrorist groups.
5. There are other ways to recover your files such as restoring backups or hiring professionals to help you recover your files.

Distribution methods

Cybercriminals employ a variety of methods to spread their malicious software. The most common way for people to become infected is by installing “cracked” software.^[1] Because torrent websites and peer-to-peer file-sharing platforms are unregulated, it is impossible to know if the packages you are downloading are free of malicious files.

It is preferable to use only official web stores and developer websites. Apps that are listed on digital marketplaces must go through a rigorous review process. It may be costly, but keeping your system running smoothly may save you money in the long run. Furthermore, there are numerous free options available.

Email is another popular method. Social engineering is used by threat actors to create convincing letters that appear to be urgent messages from well-known companies. Infected attachments or malicious links are among them. You should never open email attachments from people you don't know.

Many users are also unaware of how critical it is to keep the operating system and software up to date. Hackers can use software flaws^[2] to distribute malicious programs. Security patches are regularly released by software developers and should be installed as soon as possible.

Use professional security tools to eliminate malicious files

The critical thing to do is disconnect the affected machine from the local network. For home users, disconnecting the ethernet cable should do the job. If this happened at your workplace, doing that might be complicated, so we have instructions for corporate environments at the bottom of this post.

If you try to recover your data first, it can result in permanent loss. It can also encrypt your files the second time. It will not stop until you remove the malicious files causing it first. You should not attempt removing the malicious program yourself unless you have experience.

Use anti-malware tools like SpyHunterCombo Cleaner or MalwarebytesMalwarebytes to scan your system. This security software should find all the related files and entries and remove them automatically for you. In some cases, malware is not letting you use antivirus in normal mode, so you need to access Safe Mode and perform a full system scan from there:

Windows 7 / Vista / XP

1. Click Start > Shutdown > Restart > OK.
2. When your computer becomes active, start pressing the F8 button (if that does not work, try F2, F12, Del, etc. – it all depends on your motherboard model) multiple times until you see the Advanced Boot Options window.
3. Select Safe Mode with Networking from the list.

Windows 10 / Windows 8

1. Right-click on the Start button and select Settings.
   
2. Scroll down to pick Update & Security.
3. On the left side of the window, pick Recovery.
4. Now scroll down to find the Advanced Startup section.
5. Click Restart now.
6. Select Troubleshoot.
7. Go to Advanced options.
8. Select Startup Settings.
9. Click Restart.
10. Press 5 or click 5) Enable Safe Mode with Networking.

Fix system errors to prevent Windows reinstallation

Performance, stability, and usability issues, to the point where a complete Windows reinstall is required, are expected after malware infection. These types of infections can alter the Windows registry database, damage vital bootup and other sections, delete or corrupt DLL files, etc. Once a system file is damaged by malware, antivirus software is not able to repair it. 

This is why FortectIntego was developed. It can fix a lot of the damage caused by an infection like this. Blue Screen errors, freezes, registry errors, damaged DLLs, etc., can make your computer completely unusable. By using this maintenance tool, you could avoid Windows reinstallation.

• Download the application by clicking on the link above
• Click on the ReimageRepair.exe
  
• If User Account Control (UAC) shows up, select Yes
• Press Install and wait till the program finishes the installation process
• The analysis of your machine will begin immediately
• Once complete, check the results – they will be listed in the Summary
• You can now click on each of the issues and fix them manually
• If you see many problems that you find difficult to fix, we recommend you purchase the license and fix them automatically.

File recovery options

Many people think that they can fix their files with anti-malware tools, but that is not what they are designed for. All the security tools can do is detect suspicious processes in your system and eliminate malicious files. The truth is, that the files can be restored only with a decryption key^[3] or software that only cybercriminals have.

If you did not back up your data previously, you possibly lost your files forever. You can try using data recovery software, but third-party programs cannot always decrypt the files. We suggest at least trying this method. Before proceeding, you have to copy the corrupted files and place them in a USB flash drive or another storage. And remember – only do this if you have already removed the Unknown ransomware.

Before you begin, several pointers are essential while dealing with this situation:

• Since the encrypted data on your computer might permanently be damaged by security or data recovery software, you should first make backups of it – use a USB flash drive or another storage.
• Only attempt to recover your files using this method after you perform a scan with anti-malware software.

Install data recovery software

1. Download Data Recovery Pro.
2. Double-click the installer to launch it.
3. Follow on-screen instructions to install the software.
4. As soon as you press Finish, you can use the app.
5. Select Everything or pick individual folders where you want the files to be recovered from.
6. Press Next.
7. At the bottom, enable Deep scan and pick which Disks you want to be scanned.
8. Press Scan and wait till it is complete.
9. You can now pick which folders/files to recover – don't forget you also have the option to search by the file name!
10. Press Recover to retrieve your files.