Nuksus File-locking Virus - How to remove

The new Nuksus ransomware is extremely dangerous to anyone who doesn’t have data backups. File-locking ransomware like Nuksus can lock your files and the chances of getting them back are very low. The “ransom” part of this malware means that real money is being demanded from the victims of this virus for their files being restored.

Let’s say that you have no backups: unless you have hundreds of dollars just lying around, your files are probably gone. Even if you do pay the criminals for your files, you might not get the data back, according to these statistics. Since Nuksus asks for sums from $490 to $980, the money is certainly not trivial, and a lot of Nuksus’s victims will swallow this loss and start from scratch. Just remember:

• Remove all malware before using the computer normally.
• Try out the free options to get back your files (data restore, STOPDecrypter), even if the chances of them working are not very high.

What Nuksus does

Nuksus often is downloaded in various pirated, cracked files. If you carelessly try to get a legitimate version of Windows, Office, an Adobe product, or some other expensive program, you’re at quite a risk of malware like Djvu. Nuksus is actually a version of Djvu, though a new and improved one that comes after Pedro, Roland, and many others. Djvu-type malware being hidden in illegitimate programs is nothing new, and most victims seem to contract the infections thanks to pirating. I’ve also heard of some Chromium browsers being infected, too.

Another way that Nuksus spreads is through spam emails, so just be careful before opening attachments that come from unknown senders or seem unnecessary.

It’s always important to scan a file that you downloaded before you open or run it. If you run Nuksus (unknowingly, of course), it might be too late — this ransomware disables the installed antivirus program. It then displays a fake Windows Update Window while locking your files in the background. And to make it harder for you to find out what’s happening, it blocks some websites from being accessed with the infected computer.

To push the distressed victim to pay (and leak their banking credentials and other private information because Nuksus actually installs spyware alongside itself), the virus leaves a note “_readme” in a few folders. This note is the one that tells you which email addresses to contact ([email protected], [email protected], or @datarestore (Telegram) are used for a few versions of Djvu) and what the “decryption price” (ransom) is.

The files are being renamed by appending the “.nuksus” extension after the original one. Removing it doesn’t fix anything. At the same time, Nuksus is encrypting the files with a unique key. The algorithm is secure enough, and the key is complicated enough that the encryption cannot be cracked. So, your files are locked by an elaborate cryptographic algorithm, and the decryption key (the key that can unlock your files, reversing the encryption and returning them to the original state using mathematic operations) is only known to the criminals who are responsible for the Nuksus virus.

You can see why some people just give up their data to a ransomware virus, and why mysterious people online who try to convince you that they have a miracle way to restore your files are most likely lying.

Eliminate Nuksus and fix the files

Even though the files probably can’t be restored, there is a bit of hope. First, back up your Nuksus-locked files and try following the below guide. You might be able to get back some of even all of your files. If it doesn’t work, read this post — it’s by a researcher who has developed a partial decrypter for some versions of Djvu, though Nuksus is not yet supported. But this should not be done on a computer that’s infected.

Like said earlier, the malware needs to be removed first, which can be done with the help of a professional antivirus tool, such as Spyhunter, and you might also need to kill some malicious processes to really detect and successfully remove the malware.

Automatic Malware removal tools

How to recover Nuksus File-locking Virus 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 Nuksus File-locking Virus has infiltrated to your system and then click “Next”.
• To start System restore click “Yes”.

 

Step 2. Complete removal of Nuksus File-locking Virus

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 Nuksus File-locking Virus. You can check other tools here.  

Step 3. Restore Nuksus File-locking Virus 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 Nuksus File-locking 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 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 Nuksus File-locking Virus 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.