BTTU ransomware infects systems only to encrypt all files stored in them
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BTTU ransomware is a malicious computer virus that belongs to the STOP/DJVU ransomware family. It has already infected many computers worldwide. This malware is recognizable from the .bttu extension that it appends to encrypted files. For example, files originally named 1.jpg or 2.txt will appear as 1.jpg.bttu and 2.docx.bttu after the malware affects them. There will be no way to open these files. Victims will also find out that the ransomware has dropped _readme.txt files in every computer folder – these files are widely known as “ransom notes.”
What actually happens during a ransomware attack is that the malware encrypts all files, creates ransom-demanding notes, deletes Volume Shadow Copies, it may also disable a set of various active processes so that it could encrypt associated files successfully. The aim of the malicious software is to make data that is important for the computer user inaccessible, and then demand ransom. The crooks promise to provide BTTU file decryption tool as soon as the victim pays the ransom. This is nothing else but pure extortion.
Threatening message left in _readme.txt note
The message provided in the _readme.txt ransom note explains that various data types were encrypted, and in order to regain access to them, the victim has to pay a ransom for the release of decryption tool and private key. The note specifies that those who contact the criminals within 72 hours starting from the infection timestamp will be eligible for a 50% discount and will be asked to pay $490, and those who do not squeeze in the given timeframe will be asked to pay the full amount ($980).
The ransom note also specifies that if the victim wants to test the decryption service, one can send one encrypted file to the attackers via email and also include the Personal ID provided in the _readme.txt file.
In addition, the criminals will later specify that they only accept payments made in cryptocurrency, as this gives them anonymity. In their email reply, they will specify how the victim can purchase cryptocurrency (such as Bitcoin) equal the amount in dollars and how to transfer it to the attackers.
Keep in mind that you should stick to the recommendations of cybersecurity experts and law enforcement agencies such as FBI and refuse to pay a ransom. The latter has released official recommendations for ransomware victims that suggest paying the ransom doesn’t guarantee data recovery, besides, it fuels the ransomware cycle, which means that the more money the criminals collect, the bigger attacks they can organize in the future.
Unfortunately, not every detail about the ransomware attack is explained in the ransom note. The attackers conceal the fact that the malware didn’t arrive alone, but dragged some information-stealing Trojans (VIDAR, AZORULT, RedLine) alongside it. These Stealers can grab sensitive data including passwords, cookies, browsing history, offline cryptocurrency wallets and other data that can be later used to blackmail the computer user.
Therefore, each computer user who has unfortunately fallen victim to the described malware attack should rush to remove BTTU ransomware virus right now. The provided guide at the end of this article explains how this procedure can be completed securely. If you’re interested in our software recommendations, we advise using INTEGO Antivirus for malware removal and computer protection, and also you can download RESTORO (secure download link) to identify and repair some damaged Windows OS files.
Ransomware Summary
| Name | BTTU Ransomware Virus |
| Type | Ransomware; Crypto-malware; Virtual Extortion Virus |
| Family | STOP/DJVU |
| Encryption type | RSA 2048 + Salsa20 |
| Previous versions | JYPO, KIFR, KIOP, KITZ, BOZA, BOTY, COZA (find full list here) |
| Version | 619th |
| Extension | .bttu |
| Cybercriminal emails | support@fishmail.top and datarestorehelp@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 .bttu 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 | Trojan:Win32/Azorult.FW!MTB (Microsoft), Gen:Heur.Mint.Zard.52 (B) (Emsisoft), HEUR:Trojan.Win32.Scarsi.gen (Kaspersky), Gen:Heur.Mint.Zard.52 (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 like INTEGO Antivirus. To repair virus damage on Windows OS files, download and try RESTORO (secure download link). |
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How to avoid ransomware attacks?
Ransomware, like other varieties of malware, is commonly distributed through illegal online downloads, phishing emails containing attachments, fake software update ads, or drive-by-downloads. We will go through each of these and shortly explain how you can prevent these types of attacks.
- Illegal online downloads. Cybercriminals behind STOP/DJVU variants like BTTU ransomware virus mainly use rogue websites to spread malicious code in disguise of cracked software installers. In the reality, the downloaded file is simply an executable in a password-protected archive that acts like a malware loader. Users should only choose legitimate sources to download software from in order to access genuine and secure versions.
- Phishing emails. Computer users should be very careful about things they click or files they open, especially if these are sent by an unsolicited party via email. Cybercriminals often pretend to be someone they’re not, so they might try to act like they’re writing on behalf of a certain company, online shop or parcel delivery business. Such phishing emails are typically complimented with malicious attachments that contain harmful code. Our advice is to carefully inspect each email and look for warning signs such as urgent tone, generic greeting line or suspicious sender’s email address. If you’re convinced to download the attachments, scan them with antivirus before opening them.
- Fake software update ads. Computer users should learn to identify fake online ads aggressively advertising software update tools or potentially unwanted software. These ads usually pop-up in new window or browser tab when browsing low reputation websites, such as torrent listings or movie streaming websites that provide content quite illegally. These ads usually claim that the user’s computer is at risk due to missing updates or viruses found on the system, and urges to download advertised files. Whenever such ad pops up, we recommend to close it and instead check for software updates on legitimate and official website. If you do click and download something from such ad or a fake security alerts, such event can be described as authorized drive-by-download without realisation of the consequences.
- Unauthorized Drive-by-downloads. Drive-by-download attacks are based on unintentional download of malicious code, and usually happen without user’s knowledge or interaction. Such attacks usually target software, operating system or app vulnerabilities to deliver malware. It is important to enable automatic software and operating system updates to prevent cybercriminals from using vulnerability exploits.
Most importantly, it is important to keep your computer protected with a robust antivirus at all times.
Remove BTTU Ransomware Virus and Restore Your Files
The general advice for victims of the described malware is to remove BTTU ransomware virus without a delay. Running an automatic computer virus removal software is advisable, but this task needs to be done after booting the computer into Safe Mode with Networking. Our team’s top pick is INTEGO Antivirus, which we have extensively reviewed here. Additionally, you can try to download RESTORO for virus damage repair on Windows OS files.
Afterward, do not forget to change your passwords used on the compromised computer due to the potential information theft inflicted by Trojans that accompany this ransomware.
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Our team recommends a two-step rescue plan to remove ransomware and other remaining malware from your computer, plus repair caused virus damage to the system:
STEP 1. REMOVE AUTOMATICALLY WITH ROBUST ANTIVIRUS
STEP 2. REPAIR VIRUS DAMAGE TO YOUR COMPUTER
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BTTU 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 BTTU 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 BTTU 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. 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
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Decrypt BTTU files
Fix and open large BTTU 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 BTTU 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. BTTU Ransomware Virus is considered the new STOP/DJVU variant, just like JYPO, KIFR, KIOP, KITZ, BOZA, BOTY, COZA (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 BTTU 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 BTTU 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 BTTU 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 BTTU 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 BTTU 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
You can only open BTTU files if you have the decryption key, or if you were affected by offline encryption type.
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.
Please follow the guidances provided by the official BTTU 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).
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.
Beware of fake BTTU 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 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.
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