How to remove Frogo ransomware from your operating system?

Also Known As: Frogo virus
Distribution: Low
Damage level: Severe

Frogo ransomware removal instructions

What is Frogo?

Frogo is a piece of malicious software, belonging to the Amnesia ransomware family. Systems infected with this malware have their data encrypted and they receive ransom demands for the decryption tools. During the encryption process, all affected files are retitled following this pattern, consisting of a random string of characters and the ".frogo" extension. For example, a file originally named "1.jpg" would appear as something similar to "kcTJLReLAMkMT4.frogo", and so on. After this process is complete, a ransom note - "HOW TO RECOVER ENCRYPTED FILES.TXT" is dropped into compromised folders.

The ransom-demanding message ("HOW TO RECOVER ENCRYPTED FILES.TXT") states that victims' data has been encrypted. The only way of recovering the files is by purchasing the decryption tools from the cyber criminals behind the infection. To receive these tools, users are instructed to establish contact with the criminals via email. The letters are to contain the personal ID assigned to the victims. The price of the decryption software is not mentioned, yet it will have to be paid in Bitcoin cryptocurrency (the note also contains links to sites detailing how to and from where to acquire Bitcoins). Should users fail to pay the ransom within 48 hours, a process will be initiated by which two to six files will be deleted every so often. After 90 hours, decryption will become unavailable and the data will be permanent lost. Once the ransom is paid and the transaction verified - victims will be sent the necessary recovery tools. The message ends with warnings, alerting users that removing the Frogo malicious program, running anti-virus software and/or attempting to manually decrypt the affected data - may render the files undecryptable. Additionally, the decryption tools obtained from other victims will not be compatible (i.e. unable to recover the files), as the encryption key is unique for each infection. Unfortunately, in many cases of ransomware infections, decryption is impossible - without interference of the individuals responsible for the attack. It might be, if the malware is still in development and/or has bugs (flaws). Whatever the case, it is expressly advised against communicating with and/or paying criminals. Since it is quite common for victims not to receive the promised decryption tools/software, despite them meeting the ransom demands. To prevent Frogo ransomware from further encryptions, it must be eliminated from the operating system. However, it is true that removing the malicious program will not restore already encrypted files. The sole solution is recovering them from a backup, if one was created before the infection and was stored in a separate location.

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

Frogo decrypt instructions (HOW TO RECOVER ENCRYPTED FILES.TXT)

DualShotCoronavirus and Bomba are a few examples of other ransomware-type programs. They are designed to encrypt data and demand payment for the decryption. There are two significant differences between them: the cryptographic algorithms they use (symmetric or asymmetric) and the ransom size. Digital currencies (e.g. cryptocurrencies, pre-paid vouchers, etc.) are typically used, due to transactions of them being difficult/impossible to trace. To avoid data loss, it is strongly recommended to keep backups in unplugged storage devices and/or remote servers (ideally, in multiple different locations).

How did ransomware infect my computer?

Malware (ransomware included) is primarily distributed through trojans, spam campaigns, illegal activation tools ("cracks"), illegitimate updaters and untrustworthy download sources. Trojans are malicious programs, some types of which can cause chain infections (i.e. download/install additional malware). Spam campaigns are large scale operations, during which scam emails are sent by the thousand. This mail is usually presented as "official", "important", "priority", "urgent" and similar. These emails have infectious files attached to them or the letters contain downloads links of malicious software. Rather than activate licensed product, "cracking" tools can download/install malware. Fake updaters cause infections by exploiting weaknesses of outdated products and/or simply install malicious programs instead of the updates. Dubious download channels, like: unofficial and free file-hosting websites, P2P sharing networks (BitTorrent, eMule, Gnutella, etc.) and other third party downloaders - can offer malware for downloading, disguised as or bundled with ordinary content.

Threat Summary:
Name Frogo virus
Threat Type Ransomware, Crypto Virus, Files locker
Encrypted Files Extension .frogo (files are also renamed with a string of random characters)
Cyber Criminal Contact
Detection Names Avast (Win32:Malware-gen), BitDefender (DeepScan:Generic.Ransom.Amnesia.2149), ESET-NOD32 (A Variant Of Win32/Filecoder.FS), Kaspersky (HEUR:Trojan-Ransom.Win32.Agent.gen), 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?

It is recommended not to open suspicious and/or irrelevant emails, especially any attachments or links present in them - due to risk of severe system infections. All downloads must be done from official and verified sources. It is advised to always activate and update products with tools/functions provided by genuine developers. Illegal activation tools ("cracks") and third party updaters must not be used, as they are commonly employed to proliferate malware. To ensure device and user safety, it is paramount to have a dependable anti-virus/anti-spyware suite installed. This software has to be kept up-to-date, used to run regular system scans and to remove detected/potential threats. If your computer is already infected with Frogo, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in Frogo ransomware's text file ("HOW TO RECOVER ENCRYPTED FILES.TXT"):



Your personal id

Your documents, photos, databases, save games and other important data were encrypted.
Data recovery requires a decryptor.

To receive the decryptor, you should send personal ID an email to the email address
In the letter, enter your personal ID (See at the beginning of this document).
If within 48 hours there will be no payment your files start to be deleted without a return of the not recovery !!
2-6 files will be deleted!!!
If within 90 hours there will be no payment all your data will be irretrievably removed !!
* With your e-mail
Personal id


If you do not have bitcoins
 * Create a wallet Bitcoin: hxxps://
 * Get Crypto Currency Bitcoin:
   hxxps:// (Visa/MasterCard)
   hxxps:// (What is bitcoin)

When the money transfer is confirmed, you will receive a file decryption for your computer.
After starting the decryption program all your files will be restored.


 * Do not try to uninstall the program or run antivirus software
 * Attempts to self-decrypt the files will lead to the loss of your data
 * Decoders of other users are incompatible with your data, since each user
Unique encryption key


Screenshot of files encrypted by Frogo (".frogo" extension):

Files encrypted by Frogo ransomware (.frogo extension)

Frogo 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 Frogo 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 Frogo 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 Frogo 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 Frogo 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 Frogo, 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 Frogo 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, and 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 Frogo 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.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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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
Frogo virus QR code
A QR code (Quick Response Code) is a machine-readable code which stores URLs and other information. This code can be read using a camera on a smartphone or a tablet. Scan this QR code to have an easy access removal guide of Frogo virus on your mobile device.
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