Remove KRUU Ransomware Virus (DECRYPT .kruu FILES)

remove KRUU ransomware virus and learn how to decrypt or repair files with .kruu extension (free guide)

KRUU ransomware locks computer files using encryption protocols

Contents

KRUU ransomware locks computer files using encryption protocols
Various methods cybercriminals use in spreading malware and how to protect your computer
Remove KRUU Ransomware and Decrypt Infected Files
Decrypt KRUU files
Frequently Asked Questions

KRUU is a malicious virus has just emerged from the highly destructive STOP/DJVU ransomware group. Once this ransomware-type threat lands on a computer, it will commence its attack by encrypting every file while using a unique key to lock them. Afterwards, it would initiate processes to enable it to override existing programs, thereby paving the way for it to conduct full encryption of all files found in the system. While this illegal activity is still taking place, the malware would isolate each file and add .kruu extension to it. To explain it better, here are some examples of how the files would be renamed: a file that was previously known as 1.jpg would now become 1.jpg.kruu, file 2.txt becomes 2.txt.kruu and the same action would be repeated on all other files.

To inform the computer user about what is unraveling, notifications known as _readme.txt file would be dropped in every folder. This notification also serves as a ransom note in addition to the information it passes across, notifying the victim about the use of the very strong key in encrypting all their files. Based on the successful takeover of the computer system by the cybercriminals, the victim would be expected to pay certain fees as ransom to enable him or her to receive KRUU decryption tool as promised by the cybercriminals.

Further explanations concerning the ransom note

The ransom note usually has a bold headline meant to draw the computer user’s attention. More details about the cyber-attack would also be provided under the headline. They will emphasize that important documents, videos and photos etc. have all been encrypted using a very special and complex key that can’t be breached. Therefore, the only way out for the victim to recover their encrypted files is to pay the ransom requested by the cybercriminals. Once that is done, decryption tools and software would be sent across to them. No other plea or concession would be entertained and failure to meet their demand would lead to an irreversible loss of all the encrypted files.

To provide a communication channel between the attacker and victim, two email addresses would also be made available in the ransom note i.e. manager@time2mail.ch and supportsys@airmail.cc. Even though the emails are provided to enable further talks towards making payment, the cybercriminals would still maintain a rigid stance on their demands. However, they may suggest that victims can forward samples of the encrypted files to them so they could provide text decryptions as a way of displaying their expertise but would still warn that such samples must contain information they could perceive as crucial.
At this point, they would state that the ransom fee or decryption tool would cost a total of $980.

However, if the victim is willing to pay within 72 hours i.e. 3 days after being notified, it would enable them to leverage their 50% discount policy, thereby bringing the ransom fees down to $490. The terms and conditions don’t end there, as the cybercriminals would also mandate their victim to make use of cryptocurrency when paying the ransom. The reason for choosing such a medium of payment is to prevent anything that could potentially expose their location or identity.

Shown below is _readme.txt ransom note cybercriminals usually forward to all folders.

FBI as well as other cybersecurity experts has warned victims never to pay ransom, no matter how difficult the situation may be. The major reasons why they advocate this is stated below:

In certain countries, it might be against the law to pay ransom;
Ransom payment does not guarantee file recovery;
Paying ransom enriches cybercriminals thus motivating to commit more fraud;
More money at the disposal of cybercriminals would enable them to increase their capacity.

Aside these facts listed above, when victims pay ransom they make themselves vulnerable to future attacks since the cybercriminals would see them as a willing cash cow they can always milk to assuage their greed.

Other risk factors associated with ransomware attacks

Most STOP/DJVU ransomware variants, including this latest one are known to passively release other types of virus on the already compromised computer. Typical ones that are often dropped are AZORULT and VIDAR Trojans. These secondary viruses are equally as dangerous and can be used by the cybercriminals to covertly obtain sensitive personal information, including passwords, banking details, cryptocurrency wallets, and browsing history, among others. Once the cybercriminals succeed in getting them, it gives them more opportunities to perpetrate additional crimes.

Considering these threats and how vulnerable victims could be, KRUU ransomware virus must be removed without further delay anytime it infects any computer. The recommended safe way of getting rid of it is to make use of Safe Mode with Networking option when booting the compromised computer before downloading genuine antivirus software. Such antivirus should be updated at all times for maximum protection. In addition to that, we also recommend the use of RESTORO software in repairing some of the damaged files.

Ransomware Summary

Name	KRUU Ransomware Virus
Type	Ransomware; Crypto-malware; Virtual Extortion Virus
Family	STOP/DJVU
Encryption type	RSA 2048 + Salsa20
Previous versions	MINE, XCVF, SIJR, EGFG, BBNM, IFLA, KRUU (find full list here)
Version	477th
Extension	.kruu
Cybercriminal emails	manager@time2mail.ch and supportsys@airmail.cc
Additional malware dropped	Azorult or Vidar Trojan
Damage	The ransomware uses encryption to maliciously modify all files on the PC and marks their original names with .kruu extension. Ransom notes called as _readme.txt will be dropped in every computer folder. This piece of malware usually drags VIDAR Stealer alongside it and also eliminates VSS from the system. On top of that, it tends to modify Windows HOSTS file to restrict computer user’s access to cybersecurity-related websites online.
Ransom note	_readme.txt
Ransom demand	$490-$980 in Bitcoin
Distribution	Victims often download this ransomware along illegal torrent downloads, cracked software, activators, key generators or tools like KMSPico.
Known software cracks to contain this malware	Corel Draw, Tenorshare 4ukey, Adobe Photoshop, Cubase, Adobe Illustrator, Internet Download Manager, Tally, League of Legends.
Detection names	Ransom:Win32/StopCrypt.PAL!MTB (Microsoft), Trojan.Crypt (A) (Emsisoft), HEUR:Trojan-Ransom.Win32.Stop.gen (Kaspersky), Trojan.GenericKD.47850419 (BitDefender), Trojan.MalPack.GS (Malwarebytes), ML.Attribute.HighConfidence (Symantec) see all detection name variations on VirusTotal
Removal	Remove ransomware and related malware from your PC using trustworthy software. To repair virus damage on Windows OS files, consider scanning with RESTORO (secure download link).

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Scan your system for FREE to detect security, hardware and stability issues. You can use the scan results and try to remove threats manually, or you can choose to get the full version of software to fix detected issues and repair virus damage to Windows OS system files automatically. Includes Avira spyware/malware detection & removal engine.

This is how encrypted files look like.

Various methods cybercriminals use in spreading malware and how to protect your computer

There are several fraudulent methods cybercriminals exploit in their desperate attempts to distribute malware, including malicious email attachments, pirated activation keys or “cracks”, phishing and fake/deceptive ads, among others. They frequently make use of online torrents platforms for uploads of pirated software contents embedded with malware. Therefore, the use of such illegal items in any form or even to download is highly prohibited to ensure your computer remains safe. Computer users should only make use of software content produced by genuine brands and also distributed by or their affiliated partners.

Cybercriminals usually exploit files like PDF, Microsoft Word, JavaScript, etc., in embedding and distributing malware to unsuspecting computer users. To deceive their target audience, they often make use of transactional terms like Tracking Number, Pending Payment, and Invoice etc. The aim is to bait the computer user into opening the attachments which would automatically result in malware infection.

Alternatively, they may even spoof their actual address to make it appear different or like that of a popular brand, complete with their logo. Due to such impersonation, computer users should be careful when going through their inboxes. Any email that appears weird or is not from a known source shouldn’t be opened.

It is also important to ignore any website that claims to have tools or software that works perfectly against STOP/DJVU ransomware encryptions. More often than not, such websites are used for fraudulent purposes. At the moment, the two brands that have been recognized for having effective tools against these malware variants are Emsisoft and DiskTuna.

Remove KRUU Ransomware and Decrypt Infected Files

The most effective way to remove KRUU ransomware virus is when the compromised computer is powered on using Safe Mode with Networking option. Once that is done, genuine antivirus software should be activated and kept running for optimal results.

The following should be done now that KRUU ransomware virus has been removed:

Report to the nearest law enforcement agency.
Consider the use of any available backup device to restore lost files.
Learn further about STOP/DJVU ransomware strain and how files locked by its versions could be decrypted.
All passwords associated with the compromised computer must be changed immediately.

Before we conclude, remember that RESTORO can be downloaded and used in salvaging some of the damaged files. Also note that installation and periodic updating of genuine antivirus software on your computer is very important as a way of safeguarding your computer and the files contained in it.

OUR GEEKS RECOMMEND

Our team recommends removing malware using a professional antivirus software and then using the following tool to repair virus damage to Windows system files:

REPAIR VIRUS DAMAGE TO YOUR COMPUTER

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RESTORO provides a free scan that helps to identify hardware, security and stability issues and presents a comprehensive report which can help you to locate and fix detected issues manually. It is a great PC repair software to use after you remove malware with professional antivirus. The full version of software will fix detected issues and repair virus damage caused to your Windows OS files automatically.

RESTORO uses AVIRA scanning engine to detect existing spyware and malware. If any are found, the software will eliminate them.

Read full review here.

GeeksAdvice.com editors select recommended products based on their effectiveness. We may earn a commission from affiliate links, at no additional cost to you. Learn more.

KRUU Ransomware Virus Removal Guidelines

Method 1. Enter Safe Mode with Networking

Step 1. Start Windows in Safe Mode with Networking

Before you try to remove KRUU Ransomware Virus virus, you must start your computer in Safe Mode with Networking. Below, we provide the easiest ways to boot PC in the said mode, but you can find additional ones in this in-depth tutorial on our website – How to Start Windows in Safe Mode. Also, if you prefer a video version of the tutorial, check our guide How to Start Windows in Safe Mode on Youtube.

Instructions for Windows XP/Vista/7 users

First of all, turn off your PC. Then press the Power button to start it again and instantly start pressing F8 button on your keyboard repeatedly in 1-second intervals. This launches the Advanced Boot Options menu.
Use arrow keys on the keyboard to navigate down to Safe Mode with Networking option and press Enter.

Instructions for Windows 8/8.1/10/11 users

Open Windows Start menu, then press down the Power button. On your keyboard, press down and hold the Shift key, and then select Restart option.
This will take you to Windows Troubleshoot screen. Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Tip: If you can't find Startup Settings, click See more recovery options.
In Startup Settings, press the right key between F1-F9 to enter Safe Mode with Networking. In this case, it is the F5 key.

Step 2. Remove files associated with the virus

Now, you can search for and remove KRUU Ransomware Virus files. It is very hard to identify files and registry keys that belong to the ransomware virus, Besides, malware creators tend to rename and change them repeatedly. Therefore, the easiest way to uninstall such type of a computer virus is to use a reliable security program such as INTEGO Antivirus, which also includes data recovery software. For virus damage repair, consider using RESTORO.

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Method 2. Use System Restore

In order to use System Restore, you must have a system restore point, created either manually or automatically.

Step 1. Boot Windows in Safe Mode with Command Prompt

Instructions for Windows XP/Vista/7 users

Shut down your PC. Start it again by pressing the Power button and instantly start pressing F8 button on your keyboard repeatedly in 1-second intervals. You will see Advanced Boot Options menu.
Using arrow keys on the keyboard, navigate down to Safe Mode with Command Prompt option and press Enter.

Instructions for Windows 8/8.1/10/11 users

Launch Windows Start menu, then click the Power button. On your keyboard, press down and hold the Shift key, and then choose Restart option with the mouse cursor.
This will take you to Windows Troubleshoot screen. Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Tip: If you can't find Startup Settings, click See more recovery options.
In Startup Settings, press the right key between F1-F9 to enter Safe Mode with Command Prompt. In this case, press F6 key.

Step 2. Start System Restore process

Wait until system loads and command prompt shows up.
Type cd restore and press Enter, then type rstrui.exe and press Enter. Or you can just type %systemroot%system32restorerstrui.exe in command prompt and hit Enter.
This launches System Restore window. Click Next and then choose a System Restore point created in the past. Choose one that was created before ransomware infection.
Click Yes to begin the system restoration process.

After restoring the system, we recommend scanning the system with antivirus or anti-malware software. In most cases, there won't be any malware remains, but it never hurts to double-check. In addition, we highly recommend checking ransomware prevention guidelines provided by our experts in order to protect your PC against similar viruses in the future.

Alternative software recommendations

Malwarebytes Anti-Malware

Removing spyware and malware is one step towards cybersecurity. To protect yourself against ever-evolving threats, we strongly recommend purchasing a Premium version of Malwarebytes Anti-Malware, which provides security based on artificial intelligence and machine learning. Includes ransomware protection. See pricing options and protect yourself now.

System Mechanic Ultimate Defense

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Disclaimer. This site includes affiliate links. We may earn a small commission by recommending certain products, at no additional cost for you. We only choose quality software and services to recommend.

Decrypt KRUU files

Fix and open large KRUU files easily:

It is reported that STOP/DJVU ransomware versions encrypt only the beginning 150 KB of each file to ensure that the virus manages to affect all files on the system. In some cases, the malicious program might skip some files at all. That said, we recommend testing this method on several big (>1GB) files first.

Create a copy of encrypted file to a separate folder using Copy > Paste commands.
Now, right-click the created copy and choose Rename. Select the KRUU extension and delete it. Press Enter to save changes.
In the prompt asking whether you want to make the changes as file might become unusable, click OK.
Try opening the file.

STOP/DJVU decryption tool usage guide

STOP/DJVU ransomware versions are grouped into old and new variants. KRUU Ransomware Virus is considered the new STOP/DJVU variant, just like MINE, XCVF, SIJR, EGFG, BBNM, IFLA, KRUU (find full list here). This means full data decryption is now possible only if you have been affected by offline encryption key. To decrypt your files, you will have to download Emsisoft Decryptor for STOP DJVU, a tool created and maintained by a genius security researcher Michael Gillespie.

Note! Please do not spam the security researcher with questions whether he can recover your files encrypted with online key - it is not possible.

In order to test the tool and see if it can decrypt KRUU files, follow the given tutorial.

Download the decryption tool from Emsisoft.
Click the little arrow next to your download and choose Show in Folder.
Now, right-click the file and choose Run as Administrator. If asked, enter administrator's password.
In UAC window, click Yes.
Click Yes to agree to software terms in both windows.
The tool will automatically include C:// disk as a location to decrypt. The file recovery tool will prepopulate the locations to scan, including connected data storage drives or network drives. Click Add folder if you wish to add additional locations.
In Options tab, you can choose to keep encrypted file copies. We recommend leaving this option selected, especially if you do not know if the decryption tool will work.
Click Decrypt to start restoring KRUU files. You will see the progress in the Results tab. Here, you can see messages from the tool, such as whether the decryption procedure is successful, or you need to wait for an update.
You might also be informed that online key was used to encrypt your files. In such case, the decryption tool won't work for you, and the only way to recover your files is to use a data backup.

Meanings of decryptor's messages

The KRUU decryption tool might display several different messages after failed attempt to restore your files. You might receive one of the following messages:

Error: Unable to decrypt file with ID: [example ID]

This message typically means that there is no corresponding decryption key in the decryptor's database.

No key for New Variant online ID: [example ID]
Notice: this ID appears to be an online ID, decryption is impossible

This message informs that your files were encrypted with online key, meaning no one else has the same encryption/decryption key pair, therefore data recovery without paying the criminals is impossible.

Result: No key for new variant offline ID: [example ID]
This ID appears to be an offline ID. Decryption may be possible in the future.

If you were informed that an offline key was used, but files could not be restored, it means that the offline decryption key isn't available yet. However, receiving this message is extremely good news, meaning that it might be possible to restore your KRUU extension files in the future. It can take a few months until the decryption key gets found and uploaded to the decryptor. We recommend you to follow updates regarding the decryptable DJVU versions here. We strongly recommend backing up your encrypted data and waiting.

Report Internet crime to legal departments

Victims of KRUU Ransomware Virus should report the Internet crime incident to the official government fraud and scam website according to their country:

In the United States, go to the On Guard Online website.
In Australia, go to the SCAMwatch website.
In Germany, go to the Bundesamt für Sicherheit in der Informationstechnik website.
In Ireland, go to the An Garda Síochána website.
In New Zealand, go to the Consumer Affairs Scams website.
In the United Kingdom, go to the Action Fraud website.
In Canada, go to the Canadian Anti-Fraud Centre.
In India, go to Indian National Cybercrime Reporting Portal.
In France, go to the Agence nationale de la sécurité des systèmes d’information.

If you can't find an authority corresponding to your location on this list, we recommend using any search engine to look up "[your country name] report cyber crime". This should lead you to the right authority website. We also recommend staying away from third-party crime report services that are often paid. It costs nothing to report Internet crime to official authorities.

Another recommendation is to contact your country's or region’s federal police or communications authority.

Frequently Asked Questions

✓ How can I open .KRUU files?

You can only open KRUU files if you have the decryption key, or if you were affected by offline encryption type.

✓ How do I know if my files were encrypted with offline or online encryption?

To figure out whether you were affected by offline encryption, please go to C:/SystemID/PersonalID.txt and see if the string inside of it ends in t1. You can also try using Emsisoft Decryptor for STOP/DJVU.

✓ My files contain very important information (family memories). Every tool I used says it is impossible to decrypt. What should I do?

Please follow the guidances provided by the official KRUU decryption tools and believe what they say. If they say it is impossible to decrypt, it really is so. There is no magic tool or human capable of decrypting your files hiding somewhere. Encryption is a technique created to be nearly impossible to decrypt without a special private key (held by the criminals).

✓ I am afraid virus is still in my computer system. What should I do?

We advise scanning with anti-virus, anti-malware, malware removal tools or software like RESTORO to eliminate virus damage on the system. If you do not trust using a single tool, try running one after another. However, we do not recommend keeping several security programs on a computer at once as they can interfere with each other's work.

✓ I saw several Youtube videos suggesting secret decryption tools. Can I trust them?

Beware of fake KRUU decryption tools circulating around the web. Cyber criminals are uploading them to various shady websites, also might be promoting them via suspicious Youtube videos. These programs can infect your computer even more heavily (Trojans, miners, etc.). We suggest being extremely cautious around the web. If there will be an official STOP/DJVU decryption tool available, it will be widely discussed in public media.

Norbert Webb

Norbert Webb is the head of Geek’s Advice team. He is the chief editor of the website who controls the quality of content published. The man also loves reading cybersecurity news, testing new software and sharing his insights on them. Norbert says that following his passion for information technology was one of the best decisions he has ever made. “I don’t feel like working while I’m doing something I love.” However, the geek has other interests, such as snowboarding and traveling.