1btc (.1btc) ransomware virus - removal and decryption options
Written by Tomas Meskauskas on (updated)
What is the 1btc (MedusaLocker) ransomware?
Belonging to the MedusaLocker ransomware family, 1btc is a malicious program. It operates by encrypting data and demanding payment for decryption tools. I.e., affected files are rendered inaccessible and victims receive ransom demands to recover access to their data.
During the encryption process, files are appended with the ".1btc" extension. For example, a file originally named something like "1.jpg" would appear as "1.jpg.1btc", "2.jpg" as "2.jpg.1btc", and so on.
Once this process is complete, ransom-demand messages within "!!!HOW_TO_DECRYPT!!!.mht" files are dropped into compromised folders.
Screenshot of files encrypted by 1btc (MedusaLocker) ransomware (".1btc" extension):
The ransom message ("!!!HOW_TO_DECRYPT!!!.mht") informs victims that their important data has been encrypted using the AES-256, RSA-2048, and ChaCha cryptographic algorithms. Additionally, sensitive/confidential content has been exfiltrated from the system.
The message states that, should victims refuse to meet the cyber criminals' demands, the stolen data will be publicized and their partners/customers informed of the leak via phone or email.
To recover their files and prevent publication, victims are instructed to send a message using the provided email addresses and initiate the negotiations within 72 hours. After the deadline passes, the downloaded material will be publicized and/or sold to the victims' competitors.
Decryption can be tested by sending the criminals up to three small encrypted files, which do not contain valuable information. The restoration of the test files will serve as 'proof' that decryption is possible. The criminals' replies may arrive in "Spam/Junk" email folders, so users are advised to check them.
Should no response arrive within 24 hours, victims are instructed to use a different email service provider. The message is concluded with a warning, stating that any modification to the compromised files (e.g., attempts at manual decryption) will render them undecryptable.
In many cases of ransomware infections, decryption is impossible without the cyber criminals' involvement, unless in rare cases the malware is still in development or has bugs/flaws. Regardless, you are expressly advised against communicating with or paying any criminals. Despite meeting the ransom demands, victims often do not receive the promised decryption tools/software. Therefore, they experience financial loss and their data remains encrypted - essentially useless.
To prevent 1btc (MedusaLocker) ransomware from further encryptions, it must be eliminated from the operating system. Unfortunately, removal will not restore already affected files. The only solution is recovering them from a backup, if one was made before the infection and stored in a separate location.
DearCry, Duk, Reig, and Restore19 are some examples of other ransomware-type programs. They are designed to encrypt data and demand payment for decryption tools/software.
There are two significant differences between these programs/infections: the cryptographic algorithms they use (symmetric or asymmetric) and ransom size. Digital currencies (e.g., cryptocurrencies, pre-paid vouchers, gift cards, etc.) are typically used because these transactions are difficult/impossible to trace.
To avoid permanent data loss, keep backups on remote servers and/or unplugged storage devices. It is best to store backups in several different locations.
How did ransomware infect my computer?
Ransomware and other malware infections are commonly spread through malspam campaigns, untrusted file/software download sources, fake (third party) software updating tools, Trojans and unofficial software activation tools.
Using malspam, criminals send emails that have a malicious file attached, or include a website link designed to download a malicious file. Their main goal is to trick recipients into executing the file, which then infects the computer with malware. Cyber criminals usually attach a Microsoft Office document, archive file (ZIP, RAR), PDF document, executable file (.exe) or JavaScript file, and wait until recipients open it.
Note that malicious MS Office documents can install malware only when users enable editing/content (macros commands). If the documents are opened with MS Office versions prior to 2010, however, the documents install malicious software automatically, since these older versions do not include "Protected View" mode.
Examples of untrusted file and software download sources are Peer-to-Peer networks (torrent clients), free file hosting websites, freeware download sites, and unofficial web pages. These are used to distribute malicious files by disguising them as legitimate and regular. When users download and open (execute) the files, however, they inadvertently install malware.
Fake software updating tools cause damage by installing malware rather than updates/fixes for installed software, or by exploiting bugs/flaws of outdated software. Trojans are malicious programs that can cause chain infections by installing other software of this kind. Note that malware can only be distributed in this way if Trojans are already installed on computers.
Unofficial activation ('cracking') tools are illegal programs that supposedly activate licensed software free of charge and bypass activation, however, they often install other malicious programs instead.
| Name | 1btc (MedusaLocker) virus |
| Threat Type | Ransomware, Crypto Virus, Files locker |
| Encrypted Files Extension | .1btc |
| Ransom Demand Message | !!!HOW_TO_DECRYPT!!!.mht |
| Cyber Criminal Contact | cmd@jitjat.org and dirhelp@keemail.me |
| Detection Names | Avast (Win64:Malware-gen), BitDefender (Trojan.GenericKD.36458043), ESET-NOD32 (A Variant Of Win64/Filecoder.DF), Kaspersky (Trojan.Win32.DelShad.fyr), Microsoft (Ransom:Win32/MedusaLocker.MK!MTB), 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 Combo Cleaner. |
How to protect yourself from ransomware infections
Download software and files from official websites and via direct links. It is not safe to use torrent clients, eMule (or other Peer-to-Peer networks), third party downloaders, unofficial websites or other sources of this kind.
Avoid third party installers. Check "Advanced", "Custom" and other settings, and decline offers to download or install unwanted software. Do not click ads that are displayed on dubious websites, since they can open other untrusted websites or even cause unwanted downloads and installations.
Remove any unwanted, suspicious applications (extensions, add-ons, and plug-ins) that are installed on the browser. The same should be applied to programs of this kind that are installed on the operating system.
Regularly scan your computer with reputable antivirus or anti-spyware software and keep this software up to date.
If your computer is already infected with 1btc (MedusaLocker), we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate this ransomware.
The appearance of 1btc (MedusaLocker) ransomware ransom message (GIF):
Text presented in 1btc (MedusaLocker) ransomware ransom message ("!!!HOW_TO_DECRYPT!!!.mht"):
All your valiable data has been encrypted!
Hello!
Sorry, but we have inform you that your order has been blocked due to the issue of securities. Make sure your data is not blocked. All your valuable files were encrypted with strong encryption algorithms AES-256 + RSA-2048 + CHACHA and renamed. You can read about these algorithms in Google. Your unique encryption key is stored securely on our server and your data can be decrypted quickly and securely.
We can prove that we can decrypt all of your data. Please just send us 3 small encrypted files which are randomly stored on your server. We will decrypt these files and send them to you as a proof. Please note that files for free test decryption should not contain valuable information.
As you know information is the most valuable resource in the world. That's why all of your confidential data was uploaded to our servers. If you need proof, just write us and we will show you that we have your files. If you will not start a dialogue with us in 72 hours we will be forced to publish your files in the Darknet. Your customers and partners will be informed about the data leak by email or phone.
This way, your reputation will be ruined. If you will not react, we will be forced to sell the most important information such as databases to interested parties to generate some profit.
Please understand that we are just doing our job. We don't want to harm your company. Think of this incident as an opportunity to improve your security. We are opened for dialogue and ready to help you. We are professionals, please don't try to fool us.
If you want to resolve this situation,
please write to ALL of these 2 email addresses:
cmd@jitjat.org
dirhelp@keemail.me
In subject line please write your ID: -
Important!
* We asking to send your message to ALL of our 2 email adresses because for various reasons, your email may not be delivered.
* Our message may be recognized as spam, so be sure to check the spam folder.
* If we do not respond to you within 24 hours, write to us from another email address. Use Gmail, Yahoo, Hotmail, or any other well-known email service.
Important
* Please don't waste the time, it will result only additinal damage to your company!
* Please do not try to decrypt the files yourself. We will not be able to help you if files will be modified.
Screenshot of the ransom note:
1btc (MedusaLocker) ransomware removal:
Instant automatic malware removal:
Manual threat removal might be a lengthy and complicated process that requires advanced IT skills. Combo Cleaner 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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Video suggesting what steps should be taken in case of a ransomware infection:
Quick menu:
- What is 1btc (MedusaLocker) virus?
- STEP 1. Reporting ransomware to authorities.
- STEP 2. Isolating the infected device.
- STEP 3. Identifying the ransomware infection.
- STEP 4. Searching for ransomware decryption tools.
- STEP 5. Restoring files with data recovery tools.
- STEP 6. Creating data backups.
If you are a victim of a ransomware attack we recommend reporting this incident to authorities. By providing information to law enforcement agencies you will help track cybercrime and potentially assist in the prosecution of the attackers. Here's a list of authorities where you should report a ransomware attack. For the complete list of local cybersecurity centers and information on why you should report ransomware attacks, read this article.
List of local authorities where ransomware attacks should be reported (choose one depending on your residence address):
USA - Internet Crime Complaint Centre IC3
United Kingdom - Action Fraud
Spain - Policía Nacional
France - Ministère de l'Intérieur
Germany - Polizei
Italy - Polizia di Stato
The Netherlands - Politie
Poland - Policja
Portugal - Polícia Judiciária
Isolating the infected device:
Some ransomware-type infections are designed to encrypt files within external storage devices, infect them, and even spread throughout the entire local network. For this reason, it is very important to isolate the infected device (computer) as soon as possible.
Step 1: Disconnect from the internet.
The easiest way to disconnect a computer from the internet is to unplug the Ethernet cable from the motherboard, however, some devices are connected via a wireless network and for some users (especially those who are not particularly tech-savvy), disconnecting cables may seem troublesome. Therefore, you can also disconnect the system manually via Control Panel:
Navigate to the "Control Panel", click the search bar in the upper-right corner of the screen, enter "Network and Sharing Center" and select search result: 
Click the "Change adapter settings" option in the upper-left corner of the window: 
Right-click on each connection point and select "Disable". Once disabled, the system will no longer be connected to the internet. To re-enable the connection points, simply right-click again and select "Enable". 
Step 2: Unplug all storage devices.
As mentioned above, ransomware might encrypt data and infiltrate all storage devices that are connected to the computer. For this reason, all external storage devices (flash drives, portable hard drives, etc.) should be disconnected immediately, however, we strongly advise you to eject each device before disconnecting to prevent data corruption:
Navigate to "My Computer", right-click on each connected device, and select "Eject": 
Step 3: Log-out of cloud storage accounts.
Some ransomware-type might be able to hijack software that handles data stored within "the Cloud". Therefore, the data could be corrupted/encrypted. For this reason, you should log-out of all cloud storage accounts within browsers and other related software. You should also consider temporarily uninstalling the cloud-management software until the infection is completely removed.
Identify the ransomware infection:
To properly handle an infection, one must first identify it. Some ransomware infections use ransom-demand messages as an introduction (see the WALDO ransomware text file below).
This, however, is rare. In most cases, ransomware infections deliver more direct messages simply stating that data is encrypted and that victims must pay some sort of ransom. Note that ransomware-type infections typically generate messages with different file names (for example, "_readme.txt", "READ-ME.txt", "DECRYPTION_INSTRUCTIONS.txt", "DECRYPT_FILES.html", etc.). Therefore, using the name of a ransom message may seem like a good way to identify the infection. The problem is that most of these names are generic and some infections use the same names, even though the delivered messages are different and the infections themselves are unrelated. Therefore, using the message filename alone can be ineffective and even lead to permanent data loss (for example, by attempting to decrypt data using tools designed for different ransomware infections, users are likely to end up permanently damaging files and decryption will no longer be possible even with the correct tool).
Another way to identify a ransomware infection is to check the file extension, which is appended to each encrypted file. Ransomware infections are often named by the extensions they append (see files encrypted by Qewe ransomware below).
This method is only effective, however, when the appended extension is unique - many ransomware infections append a generic extension (for example, ".encrypted", ".enc", ".crypted", ".locked", etc.). In these cases, identifying ransomware by its appended extension becomes impossible.
One of the easiest and quickest ways to identify a ransomware infection is to use the ID Ransomware website. This service supports most existing ransomware infections. Victims simply upload a ransom message and/or one encrypted file (we advise you to upload both if possible).
The ransomware will be identified within seconds and you will be provided with various details, such as the name of the malware family to which the infection belongs, whether it is decryptable, and so on.
Example 1 (Qewe [Stop/Djvu] ransomware):
Example 2 (.iso [Phobos] ransomware):
If your data happens to be encrypted by ransomware that is not supported by ID Ransomware, you can always try searching the internet by using certain keywords (for example, a ransom message title, file extension, provided contact emails, crypto wallet addresses, etc.).
Search for ransomware decryption tools:
Encryption algorithms used by most ransomware-type infections are extremely sophisticated and, if the encryption is performed properly, only the developer is capable of restoring data. This is because decryption requires a specific key, which is generated during the encryption. Restoring data without the key is impossible. In most cases, cybercriminals store keys on a remote server, rather than using the infected machine as a host. Dharma (CrySis), Phobos, and other families of high-end ransomware infections are virtually flawless, and thus restoring data encrypted without the developers' involvement is simply impossible. Despite this, there are dozens of ransomware-type infections that are poorly developed and contain a number of flaws (for example, the use of identical encryption/decryption keys for each victim, keys stored locally, etc.). Therefore, always check for available decryption tools for any ransomware that infiltrates your computer.
Finding the correct decryption tool on the internet can be very frustrating. For this reason, we recommend that you use the No More Ransom Project and this is where identifying the ransomware infection is useful. The No More Ransom Project website contains a "Decryption Tools" section with a search bar. Enter the name of the identified ransomware, and all available decryptors (if there are any) will be listed.
Restore files with data recovery tools:
Depending on the situation (quality of ransomware infection, type of encryption algorithm used, etc.), restoring data with certain third-party tools might be possible. Therefore, we advise you to use the Recuva tool developed by CCleaner. This tool supports over a thousand data types (graphics, video, audio, documents, etc.) and it is very intuitive (little knowledge is necessary to recover data). In addition, the recovery feature is completely free.
Step 1: Perform a scan.
Run the Recuva application and follow the wizard. You will be prompted with several windows allowing you to choose what file types to look for, which locations should be scanned, etc. All you need to do is select the options you're looking for and start the scan. We advise you to enable the "Deep Scan" before starting, otherwise, the application's scanning capabilities will be restricted.
Wait for Recuva to complete the scan. The scanning duration depends on the volume of files (both in quantity and size) that you are scanning (for example, several hundred gigabytes could take over an hour to scan). Therefore, be patient during the scanning process. We also advise against modifying or deleting existing files, since this might interfere with the scan. If you add additional data (for example, downloading files/content) while scanning, this will prolong the process:
Step 2: Recover data.
Once the process is complete, select the folders/files you wish to restore and simply click "Recover". Note that some free space on your storage drive is necessary to restore data:
Create data backups:
Proper file management and creating backups is essential for data security. Therefore, always be very careful and think ahead.
Partition management: We recommend that you store your data in multiple partitions and avoid storing important files within the partition that contains the entire operating system. If you fall into a situation whereby you cannot boot the system and are forced to format the disk on which the operating system is installed (in most cases, this is where malware infections hide), you will lose all data stored within that drive. This is the advantage of having multiple partitions: if you have the entire storage device assigned to a single partition, you will be forced to delete everything, however, creating multiple partitions and allocating the data properly allows you to prevent such problems. You can easily format a single partition without affecting the others - therefore, one will be cleaned and the others will remain untouched, and your data will be saved. Managing partitions is quite simple and you can find all the necessary information on Microsoft's documentation web page.
Data backups: One of the most reliable backup methods is to use an external storage device and keep it unplugged. Copy your data to an external hard drive, flash (thumb) drive, SSD, HDD, or any other storage device, unplug it and store it in a dry place away from the sun and extreme temperatures. This method is, however, quite inefficient, since data backups and updates need to be made regularly. You can also use a cloud service or remote server. Here, an internet connection is required and there is always the chance of a security breach, although it's a really rare occasion.
We recommend using Microsoft OneDrive for backing up your files. OneDrive lets you store your personal files and data in the cloud, sync files across computers and mobile devices, allowing you to access and edit your files from all of your Windows devices. OneDrive lets you save, share and preview files, access download history, move, delete, and rename files, as well as create new folders, and much more.
You can back up your most important folders and files on your PC (your Desktop, Documents, and Pictures folders). Some of OneDrive’s more notable features include file versioning, which keeps older versions of files for up to 30 days. OneDrive features a recycling bin in which all of your deleted files are stored for a limited time. Deleted files are not counted as part of the user’s allocation.
The service is built using HTML5 technologies and allows you to upload files up to 300 MB via drag and drop into the web browser or up to 10 GB via the OneDrive desktop application. With OneDrive, you can download entire folders as a single ZIP file with up to 10,000 files, although it can’t exceed 15 GB per single download.
OneDrive comes with 5 GB of free storage out of the box, with an additional 100 GB, 1 TB, and 6 TB storage options available for a subscription-based fee. You can get one of these storage plans by either purchasing additional storage separately or with Office 365 subscription.
Creating a data backup:
The backup process is the same for all file types and folders. Here’s how you can back up your files using Microsoft OneDrive
Step 1: Choose the files/folders you want to backup.
Click the OneDrive cloud icon to open the OneDrive menu. While in this menu, you can customize your file backup settings.
Click Help & Settings and then select Settings from the drop-down menu.
Go to the Backup tab and click Manage backup.
In this menu, you can choose to backup the Desktop and all of the files on it, and Documents and Pictures folders, again, with all of the files in them. Click Start backup.
Now, when you add a file or folder in the Desktop and Documents and Pictures folders, they will be automatically backed up on OneDrive.
To add folders and files, not in the locations shown above, you have to add them manually.
Open File Explorer and navigate to the location of the folder/file you want to backup. Select the item, right-click it, and click Copy.
Then, navigate to OneDrive, right-click anywhere in the window and click Paste. Alternatively, you can just drag and drop a file into OneDrive. OneDrive will automatically create a backup of the folder/file.
All of the files added to the OneDrive folder are backed up in the cloud automatically. The green circle with the checkmark in it indicates that the file is available both locally and on OneDrive and that the file version is the same on both. The blue cloud icon indicates that the file has not been synced and is available only on OneDrive. The sync icon indicates that the file is currently syncing.
To access files only located on OneDrive online, go to the Help & Settings drop-down menu and select View online.
Step 2: Restore corrupted files.
OneDrive makes sure that the files stay in sync, so the version of the file on the computer is the same version on the cloud. However, if ransomware has encrypted your files, you can take advantage of OneDrive’s Version history feature that will allow you to restore the file versions prior to encryption.
Microsoft 365 has a ransomware detection feature that notifies you when your OneDrive files have been attacked and guide you through the process of restoring your files. It must be noted, however, that if you don’t have a paid Microsoft 365 subscription, you only get one detection and file recovery for free.
If your OneDrive files get deleted, corrupted, or infected by malware, you can restore your entire OneDrive to a previous state. Here’s how you can restore your entire OneDrive:
1. If you're signed in with a personal account, click the Settings cog at the top of the page. Then, click Options and select Restore your OneDrive.
If you're signed in with a work or school account, click the Settings cog at the top of the page. Then, click Restore your OneDrive.
2. On the Restore your OneDrive page, select a date from the drop-down list. Note that if you're restoring your files after automatic ransomware detection, a restore date will be selected for you.
3. After configuring all of the file restoration options, click Restore to undo all the activities you selected.
The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups.
Frequently Asked Questions (FAQ)
How was my computer hacked and how did hackers encrypt my files?
Cybercriminals distribute ransomware through deceptive emails containing malicious attachments or links, exploiting software vulnerabilities. They also use tactics such as malicious ads, compromised websites, P2P networks, infected USB drives, pirated software, cracking tools, key generators, third-party downloaders, and free file hosting pages, typically tricking users into unwittingly downloading and executing malware.
How to open ".1btc" files?
These files are encrypted and cannot be opened without decryption.
Where should I look for free decryption tools for 1btc ransomware?
In case of a ransomware attack you should check the No More Ransom project website (more information above).
I can pay you a lot of money, can you decrypt files for me?
We do not provide this service. Decrypting files encrypted by ransomware is typically impossible without direct intervention from the developers, unless vulnerabilities in the ransomware exist. Thus, third parties offering paid decryption services are likely acting as intermediaries or engaging in fraudulent activities.
Will Combo Cleaner help me remove 1btc ransomware?
Combo Cleaner will scan your computer and eliminate active ransomware infections. While using antivirus programs is crucial for recovering from ransomware attacks, it does not decrypt encrypted files.
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