Covm Ransomware - How to remove

Covm is ransomware based on Djvu. Covm uses cryptography to corrupt media files and documents, then it renames the corrupted files by adding an additional “.covm” extension. On top of that, it installs a password-stealing trojan. You can remove Covm and the other malware, however, fixing the files could be more complicated or even impossible.

Details on Covm:

Classification	Ransomware, trojan.
Effects that Covm has	Blocked websites, broken antivirus app, disabled Task Manager, installed info stealer, broken, corrupted, encrypted files.
How to restore the files	Restore from your backup, use data recovery, check for offline ID with the free decrypter, repair the files that can be recovered.
How to delete Covm	Fix the hosts file, remove malware with your antivirus programs (Spyhunter, others), set new passwords.

How Covm infects computers and breaks files

A Covm infection is more than just ransomware: it’s also a data stealer and it messes up some settings on the infected device:

• Covm spreads on pirating sites, infects fake installers, and gets uploaded on fake download sites.
• The infected files get downloaded and installed unknowingly by the victim.
• Covm disables (or tries to) the antivirus program, blocks a bunch of websites, and disables Task Manager.
• A trojan is installed that can steal data as well as download more malware.
• Covm might delete backup files if any are stored on the computer.
• Covm tries to go online and retrieve the unique encryption ID that is required to make each victim’s encryption protected by a unique key. If it fails, it uses the hardcoded and non-unique offline ID.
• Then, Covm goes through the files and encrypt them. To work faster, it only encrypts sections of the larger files, which is still enough to break them.
• To mark the encrypted files, Covm changes their names by adding “.covm”.

Covm was released following Koti and Mzlq, other Djvu-type ransomware. The trojan that Djvu-type ransomware has been seen installing is Azorult. It can take screenshots, steal small files, take usernames, passwords, contacts, and other data saved by various online apps. If this data is used by cybercriminals, it could result in hacked and stolen accounts, as well as unauthorized purchases made in online stores. Plus, adware infections.

Covm uses secure cryptography that is not possible to break. Barring any technical issues, very victim of Covm ransomware has a unique encryption ID used on their files, which ensures that every victim has to pay their own ransom to get their files back. If multiple victims had the same encryption ID, then they also share the decryption key, which means they can decrypt their files for only one ransom payment. Of course, Covm’s devs try to avoid that.

Still, there are some things people can try to get their files back without needing to contact the criminals.

How to get the files back

Covm’s encryption is strong and can’t be broken without knowing the decryption keys. However, the only people who have the decryption keys are the criminals. As described earlier, it is possible that the offline key is required to fix your files. To find out, run the free decryptor by Emsisoft on your files. Then read the scan results.

Some file recovery options are described in more detail in the very last section of this post, such as data recovery. This one relies on you not having used the affected computer much or at all after the attack.

If you have the patience, some of the Covm-encrypted files might be partially recoverable. Because Covm only encrypts portions of the bigger files, a lot of data remains untouched. Programs just can’t correctly read or display it. Covm’s encryption can be treated as corruption. You may be able to repair the audio files, though you will lose a few seconds, which is the portion of the data that Covm encrypted. For example, here is a post discussing file reparation – notice that the author specifies that this is not decryption but reparation and the corrupted data is completely lost.

That’s very important – avoid scammers. If you look online for ways to fix your files, you will come across many scammers who promise to fix your files by decrypting them. This is impossible to do. The Emsisoft decrypter was developed by THE expert on Djvu ransomware, Covm is just so well implemented that there is no trick around its encryption and only the criminals who made Covm have the decryption keys.

How to remove Covm

Covm, Azorult, and other malware can be removed with an antivirus program (Spyhunter, others). The file that infected the computer in the first place also needs to be deleted. Though, to be able to download the antivirus program (it needs to be fixed as Covm deletes important update files), the websites that Covm blocked need to be unblocked. This is done by fixing the hosts file as described below. Also, check this post on how to enable Task Manager.

The Covm-encrypted files are not dangerous and do not need to be removed.

After the infected computer is cleaned, it is a good idea to change your passwords and make sure that 2-step verification is set where possible. This way, any passwords that Azorult might have stolen will become useless.

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

 

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

Step 3. Restore Covm 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 Covm 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 Covm 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.