Karl Ransomware - How to remove

Karl ransomware is a new infection belonging to the Djvu malware family, which is more generally described in this article. Each of these viruses results in the files on the infected computer broken and having their file types changed to KARL.

Like everything, Karl is made to generate money for its creators. If you were attacked by this malware, you must have found a text file called “_readme.txt” in some of your folders. This file is where the makers of the malware lay out their offer — they want the victims to send almost a thousand dollars to addresses they give, like [email protected] and [email protected], in exchange for regaining access to their files. Basically, Karl is an extortion virus.

Excerpt from “_readme”:

ATTENTION!

Don’t worry, you can return all your files!
All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.

On top of that, Djvu viruses do a lot of additional harm to the infected computer. They often install a password-stealer; if it successfully swipes some of your passwords, hackers can later use that data to hack your online accounts. Karl and the other cryptoviruses also delete a ton of important antivirus files in order to disable your security software, as well as block some websites. After you remove this ransomware, there’ll be a bit of work to deal with all the damage.

Remove Karl ransomware and deal with the damage:

Sources	Pirated programs Software cracks Malicious websites
Remove Karl ransomware	Scan the computer and remove all malware (SpyHunter)
Deal with the damage	Update or repair all software Change the passwords of online accounts
Restore the files	System Restore Shadow Volume Copies Data Recovery Free decryption of .karl files independent of the cryptoextortionists

How Karl infects computers

The ways that ransomware spreads to computers and servers are varied:

• It can be installed by criminals manually when they get access to a computer using Remote Desktop Protocol, when they guess or steal the username and password of one of the accounts.
• Ransomware-downloading code is hidden in doc, pdf, bat, and other files, which are attached to generic emails and sent out to thousands of recipients, hoping that some of them will open these files and accidentally download ransomware that way.
• Sometimes, ransomware is downloaded by a malicious website after simply visiting it. There could be links to the site left in social media websites, claiming that it’s something intriguing, like a new film.

However, Karl uses another way — most victims get infected after they download a crack or a pirated program. Pirated software in general is great for spreading malware because it’s not always well-regulated and the users sometimes themselves disable their anti-malware programs when they don’t want them to interfere with the program being downloaded. This is a problem when the program turns out to be Karl or another dangerous virus.

There are some things you can do to avoid such things happening again. Scan every file you download and don’t dismiss the warnings. Different threats have different names, so if the detection is unexpected, be very careful and maybe look for a safer alternative.

But it’s not always possible to avoid ransomware and other malicious programs. That’s why the best defense against Karl is being always prepared ad keeping a backup of your data. With a backup, no ransomware can take away your files because you’ll just be able to simply replace them (after you clean your computer of the infections).

How the Karl virus works

Karl uses cryptography to hide the contents of the victims’ files. This means that the files marked with the Karl extension, like picture.jpg.karl, are encrypted by the virus. An encrypted image file, if you could open it, would look like abstract nonsense; a text file would be full of random symbols. This is completely reversible — if you have the decryption key.

The biggest problem with Djvu ransomware, the reason why it’s such a devastating infection, is that the decryption key is often unknown to anyone but the criminals who created this malware. Thus, people who don’t have a thousand dollars just lying around are left with their files simply broken.

You might have heard that Djvu has a free decrypter — STOPDecrypter, a program developed by a ransomware analyst specifically for Djvu infections (of which Karl is one). Because, when forced to run without an internet connection, Djvu viruses weren’t able to sufficiently hide their decryption keys, these keys could be discovered and used on the encrypted files. Basically, a fraction of Djvu victims could get their files back thanks to STOPDecrypter.

However, Karl and some other new infections, like Meds, Peta, Gero,– they work a little differently. In the articles of those viruses there’s a link to a new decrypter that might work for some victims, but not for Karl. Still, it might be worth waiting a bit and keeping the locked “.karl” files. Some of them might be only encrypted partially (people say that the audio files are still somewhat playable), they might be reparable.

The alternative ways to get your files back, such as system restore, are described in the section below this article, but first, it’s important to get rid of any and all malware on your computer. This includes unblocking the websites that Karl blocked and using a program like SpyHunter to get rid of all viruses.

Important -- edit the hosts file to unblock security websites

TL DR : The hosts file is edited to block security sites Before the virus can be removed, it's necessary to fix the hosts file (the file which controls which addresses connect to which IPs). That is the reason the majority of security websites is inaccessible when infected with this particular parasite. This infection edits this file to stop certain websites, including anti-malware download sites, from being accessed from the infected computer, making browsers return the "This site can't be reached" error. Luckily, it's trivial to fix the file and remove the edits that were made to it.

Find and edit the hosts file

The hosts file can be found on C:/Windows/System32/Drivers/etc/hosts. If you don't see it, change the settings to see hidden files.

1. In the Start Menu, search for Control Panel.
2. In the Control Panel, find Appearance and Personalization.
3. Select Folder Options.
4. Open the View tab.
5. Open Advanced settings.
6. Select "Show hidden files...".
7. Select OK.

Open this file with administrator privileges.

1. Open the Start Menu and enter "notepad".
2. When Notepad shows up in the result, right-click on it.
3. In the menu, choose "Run as administrator"
4. File->Open and browse for the hosts file.

The hosts file should look like this: Delete additional lines that they connect various domain names to the wrong IP address. Save the file.

Download and run the antivirus program

After that, download antivirus programs and use them to remove the ransomware, the trojan, and other malware. Spyhunter (https://www.2-viruses.com/reviews/spyhunter/dwnld/).

Automatic Malware removal tools

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

 

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

Step 3. Restore Karl 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 Karl 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 Karl 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.