Protect computers from a Kvag ransomware attack

Also Known As: Kvag virus
Distribution: Moderate
Damage level: Severe

Kvag ransomware removal instructions

What is Kvag?

Kvag is ransomware-type software that belongs to the Djvu family. Like most programs of this type, Kvag is designed to prevent access to files by encoding them with a strong encryption algorithm. To decrypt files, victims are encouraged to use a decryption tool and key by paying a ransom to cyber criminals (Kvag developers). This ransomware creates a ransom message within the "_readme.txt" text file and renames victims' files by adding the ".kvag" extension to filenames. For example, "1.jpg" becomes "1.jpg.kvag".

The "_readme.txt" message states that Kvag encrypts all files, including photos, databases, documents, and other important files. The only way to recover them is to purchase a decryption tool and unique key. These cost $980, however, if contacted within the first 72 hours, cyber criminals make a 50% discount and sell decryption tools/keys for $490. In any case, it is made clear that it is impossible to receive them without payment. To get further instructions about how to pay the ransom, victims must send an email to or, which can contain one encrypted file that Kvag developers will decrypt free of charge. Decryption without specific tools held by the cyber criminals who designed the program is generally impossible. Despite this, they often send no keys/tools even after payment. To avoid being scammed, or having to pay or contact these criminals, restore your files from a backup.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

Kvag decrypt instructions

Kvag is similar to many other programs of this type. Some examples of other ransomware-type software include IS, Hermes837, and Guarded. Typically, ransomware is used to encrypt data and force people to pay for decryption of their files. Common differences are cost of decryption software/key and cryptographic algorithm (symmetric or asymmetric) used to lock data. It is generally impossible to decrypt files without the tools held only by cyber criminals, unless the ransomware is not complete, contains bugs, flaws, or other vulnerabilities. Therefore, have your data backed up and store it on a remote server (for example, Cloud) or unplugged storage device.

How did ransomware infect my computer?

Typically, cyber criminals seek to infect computers with ransomware or other malware through spam campaigns, Trojans, fake software updaters, unofficial software activation ('cracking') tools and dubious file download channels. Malware is often spread by criminals when they send emails that contain malicious attachments. These attachments are usually Microsoft Office documents, PDF files, executable files such as .exe, archive files such as ZIP, RAR, JavaScript files, and so on. Once opened, these malicious files download and install a malicious program. Trojans are malicious programs also used to proliferate malware, however, this can only be achieved if a Trojan is already installed on the system. Fake software updating tools cause damage by downloading and installing malicious programs rather than updates, or by exploiting vulnerabilities of installed, usually outdated software. Unofficial activation tools are used to bypass paid activation of licensed programs. In fact, this software often installs malware instead. Untrustworthy software download channels such as freeware download websites, free file hosting websites, Peer-to-Peer networks (torrent clients, eMule), third party downloaders, installers are also used to proliferate malware. Generally, cyber criminals upload/include malicious files or programs that are disguised as legitimate and harmless. When downloaded and opened, however, they infect computers with high-risk malware.

Threat Summary:
Name Kvag virus
Threat Type Ransomware, Crypto Virus, Files locker.
Encrypted Files Extension .kvag
Ransom Demanding Message _readme.txt
Ransom Amount $980/$490
Cyber Criminal Contact,
Detection Names Avast (Win32:Ramnit-CC [Trj]), BitDefender (Win32.Ramnit.Dam), ESET-NOD32 (A Variant Of Win32/Ramnit.CF), McAfee (W32/Ramnit!trace), Full List Of Detections (VirusTotal)
Symptoms Cannot open files stored on your computer, previously functional files now have a different extension (for example, my.docx.locked). A ransom demand message is displayed on your desktop. Cyber criminals demand payment of a ransom (usually in bitcoins) to unlock your files.
Distribution methods Infected email attachments (macros), torrent websites, malicious ads.
Damage All files are encrypted and cannot be opened without paying a ransom. Additional password-stealing trojans and malware infections can be installed together with a ransomware infection.
Malware Removal (Windows)

To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Malwarebytes.
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How to protect yourself from ransomware infections

Download files and programs from official websites and via direct download links. No other sources or tools are safe. If an email contains a web link or attachment, do not click the link or open the file. This applies to irrelevant emails that are sent from unknown, suspicious addresses. Installed software must be updated through tools or using implemented functions that are provided by official developers. The same applies to software activation. It is illegal to activate programs using unofficial activation ('cracking') tools. Avoid damage caused by malware by scanning the operating system for viruses regularly with reputable anti-virus or anti-spyware software. If your computer is already infected with Kvag, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in Kvag ransomware text file ("_readme.txt"):


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.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool:
Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that's price for you is $490.
Please note that you'll never restore your data without payment.
Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours.

To get this software you need write on our e-mail:

Reserve e-mail address to contact us:

Your personal ID:


Screenshot of a fake "Windows Update" displayed during the encryption:

kvag fake upate window

Screenshot of files encrypted by Kvag (".kvag" extension):

Files encrypted by Kvag

Kvag ransomware removal:

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Malwarebytes is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
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Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the Kvag virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the Kvag ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining Kvag ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of Kvag are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by Kvag, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as Kvag ransomware.

Note that Windows 10 Fall Creators Update includes a "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default, this feature automatically protects files stored in the Documents, Pictures, Videos, Music, Favorites as well as Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here is more information on how to get this update and add an additional protection layer from ransomware infections.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove Kvag ransomware:

About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

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Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

QR Code
Kvag virus QR code
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