How to eliminate the Guesswho ransomware infection

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

Guesswho ransomware removal instructions

What is Guesswho?

Discovered by GrujaRS, Guesswho is a high-risk ransomware infection (potentially, a new variant of Rapid ransomware), which stealthily infiltrates computers and encrypts most stored data. In doing so, Guesswho renames each encrypted file to a random string and appends the ".guesswho" extension. For example, "1.jpg" might be renamed to a filename such as "3STT6YHZTC.guesswho". Encrypted files immediately become unusable and indistinguishable. Additionally, Guesswho creates a text file ("How Recovery Files.txt") and a shortcut (""), which automatically opens the email application and creates a new message with the Guesswho developer's email address as the recipient.

The new text file contains a short message claiming that files are encrypted and that victims must contact Guesswho's developers if they want to restore them. Note that Guesswho automatically opens an identical text file called "recovery.txt" after encryption. There is no additional information and the type of cryptography used by Guesswho is currently unknown. In any case, each victim gets a unique decryption key, which is necessary to restore data. Cyber criminals store all keys on a remote server, thereby allowing them to blackmail victims - after contacting these people, victims are encouraged to pay ransoms to receive their keys. The cost is currently unconfirmed, however, criminals usually demand $500-$1500 in Bitcoins, Monero, Ethereum, DASH or another cryptocurrency. Regardless of the cost, do not pay. Research shows that cyber criminals often ignore victims, once payments are submitted. Therefore, all requests to contact these people and especially to submit payments should be ignored. Unfortunately, there are no tools capable of cracking Guesswho encryption and restoring data free of charge. Therefore, the only solution is to restore everything from a backup.

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

Guesswho decrypt instructions

Guesswho is virtually identical to dozens of other ransomware-type infections such as, Isolated, Besub, and Dcom. Most ransomware encrypts data. There are typically just two major differences: 1) cost of decryption, and; 2) type of encryption algorithm used. Unfortunately, encryptions are typically performed using RSA, AES, and other similar high-end cryptographies that generate unique decryption keys. Therefore, unless the malware is not fully developed or has certain bugs/flaws, restoring data manually without involvement of developers (contacting these people is not recommended) is impossible. Therefore, we strongly advise you to have multiple backup copies stored in different locations (e.g., remote servers and/or unplugged storage devices).

How did ransomware infect my computer?

The way developers proliferate Guesswho is currently unknown, however, infections of this type are usually distributed using spam email campaigns, third party software download sources, trojans, and fake software updaters, and 'cracks'. Spam campaigns are used to send hundreds of thousands of deceptive emails that contain malicious attachments (links and/or files) and deceptive messages encouraging recipients to open them. Attachments are also often presented as 'important documents' (receipts, invoices, bills, etc.) - these are attempts to give the impression of legitimacy and increase the chance of tricking recipients. Freeware download websites, free file hosting sites, Peer-to-Peer (P2P) networks, and other third party software download sources often present malicious executables as legitimate software. In this way, users are tricked into manual download/installation of malware. Trojans are malicious applications that stealthily infiltrate computers to inject them with additional malware. Fake updaters infect computers by exploiting outdated software bugs/flaws or simply downloading and installing malware rather than updates. Fake cracking tools also have similar behavior. Rather than providing access to paid features, they inject malware into the system.

Threat Summary:
Name Guesswho virus
Threat Type Ransomware, Crypto Virus, Files locker
Detection Names Avast (Win32:Trojan-gen), BitDefender (Generic.Ransom.Rapid2.6E832924), ESET-NOD32 (A Variant Of Win32/Filecoder.Rapid.A), Kaspersky (Trojan.Win32.DelShad.px), Full List (VirusTotal)
Encrypted Files Extension .guesswho
Ransom Demanding Message How Recovery Files.txt, recovery.txt
Cyber Criminal Contact,
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?

Be very cautious when browsing the Internet and downloading/installing/updating software. Download programs from official sources only, using direct download links. Third party downloaders/installers are likely to include rogue software and, therefore, these tools should not be used. Keep installed applications/operating systems updated, however, use implemented functions or tools provided by the official developer. Cracking installed applications is illegal (software piracy is a cyber crime) and extremely risky. Therefore, never attempt to crack installed programs. Handle all email attachments with care. Files/links received from suspicious/unrecognizable email addresses should not be opened. The same applies to attachments that are irrelevant or do not concern you. Finally, have a reputable anti-virus/anti-spyware suite installed and running, since this will detect and remove malware before it harms the system.

Screenshot of the text file ("recovery.txt") automatically opened after the encryption:

Guesswho ransomware recovery.txt

Text presented in Guesswho ransomware "How Recovery Files.txt" and "recovery.txt" files:

Hello, dear friend!
All your files have been ENCRYPTED
Do you really want to restore your files?
Write to our email -,, or,
and tell us your unique ID - ID-H4AOTYMR

Screenshot of files encrypted by Guesswho (".guesswho" extension):

Files encrypted by Guesswho

Guesswho 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 Guesswho 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 Guesswho 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 Guesswho 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 Guesswho 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 Guesswho, 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 Guesswho 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 Guesswho 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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Removal Instructions in other languages
Malware activity

Global malware activity level today:

Medium threat activity

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

QR Code
Guesswho 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 Guesswho virus on your mobile device.
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