GUESSWHO Ransomware 🔐 (.GUESSWHO File) — Removal Guide

The Guesswho virus falls within the ransomware type of malicious agent. Harmful software of such sort encrypts all user’s data on the computer (photos, documents, excel tables, music, videos, etc) and appends its own extension to every file, leaving the How Recovery Files.txt text files in each folder which contains the encrypted files.

What is Guesswho virus?

☝ A scientifically accurate denomination for the Guesswho would be “a ransomware-type infection”.

The renaming will be done according to the following pattern: .guesswho. The name of each file is changed to a random string. In the process of encryption, a file entitled, for instance, “report.docx” will be changed to “IB38191ABIC9.guesswho”.

In every folder that contains the encoded files, a How Recovery Files.txt text document will appear. It is a ransom money note. Therein you can find information on the ways of contacting the racketeers and some other remarks. The ransom note usually contains a description of how to purchase the decryption tool from the ransomware developers. You can get this decrypting software after contacting [email protected] via email. That is how they do it.

Guesswho summary:
Name Guesswho Virus
Extension .guesswho
Ransomware note How Recovery Files.txt
Contact [email protected]
Detection MSIL/Slithermon.A, MSIL/Filecoder.SLAM.A, OScope.Trojan.MSIL.Basic.8
Symptoms Your files (photos, videos, documents) get a .guesswho extension and a random string instead of their names and you can’t open them.
Fix Tool See If Your System Has Been Affected by Guesswho virus

The How Recovery Files.txt file coming in package with the Guesswho ransomware states the following:

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

In the picture below, you can see what a directory with files encrypted by the Guesswho looks like. Each filename has the “.guesswho” extension added to it.

Guesswho ransomware

Files encrypted by Guesswho ransomware

How did my computer get infected with Guesswho ransomware?

There are plenty of possible ways of ransomware injection.

There are currently three most exploited ways for criminals to have the Guesswho virus acting in your digital environment. These are email spam, Trojan introduction and peer-to-peer networks.

If you open your mailbox and see emails that look like familiar notifications from utility services companies, postal agencies like FedEx, web-access providers, and whatnot, but whose mailer is unknown to you, beware of opening those letters. They are most likely to have a malicious item enclosed in them. Thus it is even more dangerous to download any attachments that come with emails like these.

As for the peer networks like torrents or eMule, the threat is that they are even more trust-based than the rest of the Web. You can never know what you download until you get it. So you’d better be using trustworthy websites. Also, it is reasonable to scan the folder containing the downloaded files with the antivirus as soon as the downloading is complete.

How do I get rid of the Guesswho virus?

It is important to inform you that besides encrypting your data, the Guesswho virus will most likely install the Azorult Spyware on your machine to seize your credentials to various accounts (including cryptocurrency wallets). The mentioned spyware2 can derive your credentials from your browser’s auto-filling data.

Sometimes tamperers would unblock several of your files so you know that they do have the decryption tool. As Guesswho virus is a relatively recent ransomware, anti-malware designers have not yet found a method to undo its work. Nevertheless, the decoding tools are frequently updated, so the solution may soon be available.

Understandably, if the evildoers do the job of encrypting victim’s critical files, the desperate person will probably fulfill their demands. However, paying to criminals does not necessarily mean that you’re getting your data back. It is still risky. After getting the money, the racketeers may send a wrong decryption key to the injured party. There were reports about racketeers simply vanishing after getting the money without even writing back.

The best countermeasure to ransomware is to have aan OS restore point or the copies of your essential files in the cloud disk or at least on an external disk. Of course, that might be not enough. Your most important thing could be that file you were working on when it all went down. Nevertheless, it is something. It is also wise to scan your PC for viruses with the antivirus program after the OS restoration.

Guesswho is not the only ransomware of its kind, since there are other specimens of ransomware out there that act in the same manner. For instance, Eewt, Adww, Oflg, and some others. The two main differences between them and the Guesswho are the ransom amount and the encoding method. The rest is the same: files become inaccessible, their extensions changed, ransom notes appear in each folder containing encoded files.

Some fortunate people were able to decrypt the blocked files with the help of the free software provided by anti-ransomware developers. Sometimes the racketeers mistakenly send the decryption key to the wronged in the ransom note. Such an extraordinary fail allows the user to restore the files. But naturally, one should never expect such a chance. Make no mistake, ransomware is a bandits’ technology to pull the money out of their victims.

How сan I avoid ransomware infiltration?

Guesswho ransomware has no superpower, neither does any similar malware.

You can armour your PC from its infiltration in several easy steps:

  • Ignore any emails from unknown mailers with strange addresses, or with content that has nothing to do with something you are waiting for (can you win in a money prize draw without participating in it?). In case the email subject is likely something you are waiting for, check all elements of the dubious email carefully. A fake email will surely contain a mistake.
  • Do not use cracked or unknown programs. Trojans are often shared as a part of cracked software, possibly as a “patch” which prevents the license check. Understandably, untrusted programs are difficult to distinguish from reliable ones, because trojans may also have the functionality you seek. You can try searching for information about this software product on the anti-malware message boards, but the best solution is not to use such software.
Reasons why I would recommend GridinSoft3

Download Removal Tool.

Run the setup file.

Run Setup.exe
GridinSoft Anti-Malware Setup

Press “Install” button.

GridinSoft Anti-Malware Install

Once installed, Anti-Malware will automatically run.

GridinSoft Anti-Malware Splash-Screen

Wait for the Anti-Malware scan to complete.

GridinSoft Anti-Malware Scanning

Click on “Clean Now”.

GridinSoft Anti-Malware Scan Result

Frequently Asked Questions

đŸ€” Is it possible to open “.guesswho” files?

There’s no way to do it, unless the files “.guesswho” files are decrypted.

đŸ€” I really need to decrypt those “.guesswho” files ASAP. How can I do that?

It’s good if you have fаr-sightedly saved copies of these important files elsewhere. If not, there is still a function of System Restore but it needs a Restore Point to be previously saved. The rest of the methods require patience.

đŸ€” What to do if the Guesswho ransomware has blocked my computer and I can’t get the activation code.

đŸ€” What can I do right now?

Many of the blocked files might still be within your reach

  • If you exchanged your important files by email, you could still download them from your online mail server.
  • You may have shared images or videos with your friends or family members. Just ask them to post those images back to you.
  • If you have initially downloaded any of your files from the Internet, you can try to do it again.
  • Your messengers, social networks pages, and cloud drives might have all those files too.
  • It might be that you still have the needed files on your old PC, a laptop, cellphone, memory stick, etc.

USEFUL TIP: You can employ file recovery programs5 to retrieve your lost information since ransomware blocks the copies of your files, removing the original ones. In the video below, you can learn how to use PhotoRec for such a restoration, but be advised: you won’t be able to do it before you remove the virus with an antivirus program.

Also, you can contact the following governmental fraud and scam sites to report this attack:

To report the attack, you can contact local executive boards. For instance, if you live in USA, you can have a talk with FBI Local field office, IC3 or Secret Service.

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Brendan Smith

References

  1. Here’s the list of Best Data Recovery Software Of 2023.

About the author

Brendan Smith

Cybersecurity analyst covering malware families, suspicious files, and detection alerts. Brendan focuses on clear explanations of what a warning means, when it may be a false positive, and which cleanup steps are appropriate.

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