Decryption Assistant ransomware - How to remove

Decryption Assistant ransomware virus is a variant, based on a prevailing open source project Hidden Tear. It is a curious sample as it only encrypts one folder in the C: disc called “chicken”. Malware controls an AES algorithm which is applied to files, chosen for the encryption process (20 file-types are targeted). To separate affected digital data from the remaining executables, ransomware will append .pwned extension. The infection travels as an update for FlashPlayerUpdate since more than one detected sample proceeded with the FlashPlayerUpdate.exe. During the analysis of this malicious file, it was determined that it is a member of Ransom:MSIL/Ryzerlo family and these infections are based on the Hidden Tear structure.

Since this specific variant is being distributed as an update for Adobe Flash Player, we are reminding our visitors to never renew software from sources other than official websites. If a certain video crashes and an online-streaming service advises you to accept an update straight from its interface, you might agree to install something completely different and malicious. Since FlashPlayerUpdate.exe will seem like a regular file, you will have no clue that it will initiate a number of procedures and extract additional files.

After slithering into an operating system, ransomware infection will initiate stealthy behavior, consisting of modifications to Windows Registry Keys for the sake of making the payload run automatically. For this reason, an additional process should be present in the Task Manager. However, since it will look like a harmless update procedure, users probably won’t pay attention to it.

Decryption Assistant ransomware virus

Decryption Assistant virus is not expected to become an intense infection, spreading all around the globe. However, since this infection is labeled as still in the process of development, the outcomes are difficult to distinguish. For now, it is not a high-risk infection, but users are advised to avoid downloading random executables, especially the ones that are described as free software updates.

This infection sets a countdown and after it hits zero, the private key for decryption will be permanently destroyed. Disturbingly, the table that the Decryption Assistant displays includes to specific payment instructions, just plain threats and vague statements about the necessity of buying bitcoins. Even if you do receive this unfinished ransomware into your device, there will no way of paying the fee as you will not be informed about the payment plan. Even if these details would be a part of the ransom note, you would still be unadvised from paying.

Tips to avoid ransomware and stay safe

As we have already discussed, this specific variant travels as an update for Flash Player. But where can these offers be presented? One of the possible places to face a malicious app is to find it as an attachment to an email letter. If a letter you receive in your inbox contains a file, you should not recklessly download it. Additionally, updates can be presented in forms of pop-ups. Never download software from such a source as there is almost no doubt that it distributes something malicious. Redirection to unknown websites can also have some negative results. For instance, drive-by downloads can be triggered and Trojans will be secretively placed into your operating system.

The best way to stay secure yourself from ransomware is to save your digital data in multiple locations. If the copies from your hard drive get deleted or encrypted, you will be able to retrieve your files from an alternative location. There is a variety of backup storages that you can choose from. If you do not want to store your files in any of them, you can simply put additional versions of your data in USB flash drives.

Now, we will discuss the manual removal and possible methods for file-decryption. Removing ransomware can be tricky, therefore, we advise you to scan an OS with anti-malware tools for the sake of finding every potential threat. Spyhunter or Malwarebytes are one of the possible security programs to think of.

How to recover Decryption Assistant 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 RestartOK.
  • Press F8 key repeatedly until Advanced Boot Options window appears.
  • Choose Safe Mode with Command Prompt. Windows 7 enter safe mode

for Windows 8 / 10
  • Press Power at Windows login screen. Then press and hold Shift key and click Restart. Windows 8-10 restart to safe mode
  • Choose TroubleshootAdvanced OptionsStartup Settings and click Restart.
  • When it loads, select Enable Safe Mode with Command Prompt from the list of Startup Settings. Windows 8-10 enter safe mode

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.CMD commands
  • Click “Next” in the windows that appeared. Restore point img1
  • Select one of the Restore Points that are available before Decryption Assistant virus has infiltrated to your system and then click “Next”. Restore point img2
  • To start System restore click “Yes”. Restore point img3

Step 2. Complete removal of Decryption Assistant 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 Decryption Assistant virus. You can check other tools here.  

Step 3. Restore Decryption Assistant 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 Decryption Assistant virus 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 PropertiesPrevious 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.
Previous version
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.
Shadow explorer

Step 4. Use Data Recovery programs to recover Decryption Assistant 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. Data Recovery Pro
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.
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