SOS Ransomware - How to remove

The ransomware DCRTR-WDM hasn’t been idle and a new variant SOS (called that because it changes names of the files by adding “SOS” to the end) has started infecting computers. SOS is just another traditional file-encrypting extortion virus that doesn’t have a free decrypter available.

SOS follows after various other WDM infections, such as Cryptes, Java (not associated with the programming language), Parrot, Colorit, Stafs, and others. These viruses leave messages in “HOW TO DECRYPT FILES.txt” and “info.hta” files asking for money in cryptocurrency to be sent to the criminals who are responsible for the infection.

God day.
All your documents, databases, photos, videos, and staff were encrypted with a unique key.
If you want to return all your files, so write to us by mail: [email protected] In the message attach your unique ID: [random]
Do not waste your time! You risk losing all your files!

The info.hta file looks very much like Dharma, Phobos, and other ransomware infections that have copied this type of ransom note. However, the creators and the virus itself are most likely not closely related.

SOS goes through your files and encrypts them using cryptography which is secure enough that researchers haven’t broken it yet. This means that the SOS files can be decrypted in theory, but only if the decryption key (unique to each infection) is found. This key being sold to you is the “ransom” part of this malware.

Ransomware is an active threat in the online world that is lucrative for its developers and very devastating to the victims. However, SOS could be rendered almost harmless if you had file backups. If you do, you still need to remove the virus, but other than that, you are okay. The problem is that a lot of people don’t have backups which makes them very vulnerable to ransomware as well as failures of hardware. World backup day is a real thing and it’s actually needed to spread awareness of the importance of backups.

How SOS is spread

Malware, like any other program, can be installed by a computer user on their own computer. Of course, few people would want to download a program that corrupts most of your files, so malware distributors employ their imagination.

One way to trick people to install SOS ransomware is to hide it in fake software updates. It’s trivial to copy the look of some well-known and trusted program’s update pop-up and display it on some website.

Fake updates are not an excuse to avoid real updates, though. Some crypto extortionists use exploit kits to install viruses on people’s computers and the most exploits can usually be found in software that’s the most out-of-date.

Another way for SOS to spread is through email attachments. Malicious spam is sent out to thousands of people, with a downloader for SOS attached. It can be difficult to know if a file is malicious before you open it, but unfamiliar executable files (including .exe, .js, .bat, .vb) should never be run without scanning them first and macros shouldn’t be enabled at all.

If you have Remote Desktop turned on, make sure that it’s tightly secured, because many infections abuse weak RDP security and can do that in an indiscriminate, automated way.

How to remove SOS and restore the files

There is no free decryption available for files that were locked by SOS, and there might never be. However, there are some ways to restore lost data that don’t rely on decrypting it. Try System Restore — a way to go back in time to a previous state on your computer. There’s also Data Recovery software — various forensic tools that can repair files that are partially encrypted and sweep a hard disk to find files that have been completely deleted.

But if you want to use your computer normally again, the main thing to do is to remove the SOS file-locker. You can use Spyhunter or Malwarebytes to scan your computer to remove not just SOS, but any other suspicious programs. I don’t know that SOS does this, but it’s not unusual for ransomware to install additional spyware and trojan components that might continuously leak your data to the criminals if not removed.

Finally, go through your computer and update your programs, especially the security program. Think about your online accounts and make sure that you use unique passwords and 2-step verification for each one. Don’t allow the SOS infection to haunt you even after it’s gone.

Automatic Malware removal tools

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

 

Step 2. Complete removal of SOS 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 SOS Ransomware. You can check other tools here.  

Step 3. Restore SOS 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 SOS 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 SOS 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.