How to get rid of BAVACAI ransomware

What kind of malware is BAVACAI?

BAVACAI is ransomware that we discovered while examining malware samples submitted to VirusTotal. It belongs to the MedusaLocker ransomware family. BAVACAI encrypts files stored on the victim's computer and exfiltrates data from the network, then demands a ransom in exchange for decryption and to prevent publication of the stolen data.

On our test machine, this ransomware encrypted files and appended the ".BAVACAI" extension to their names. A file originally called "1.jpg" became "1.jpg.BAVACAI", "2.png" turned into "2.png.BAVACAI", and so on. After completing encryption, BAVACAI dropped a ransom note in a text file titled "WHATS_HAPPEND.txt".

Screenshot of files encrypted by BAVACAI ransomware:

BAVACAI ransom note overview

The ransom note is a text file named "WHATS_HAPPEND.txt". Despite its reassuring opener - claiming the victim's files are "perfect and safe" - the note makes clear that the attackers have both encrypted the files and stolen data from the victim's servers.

Victims are warned that the stolen data will be published within 72 hours unless they make contact. The note provides a qTox contact ID and the email address nhuvgh@outlook.com, as well as a Tor website where the exfiltrated files are stored. No specific ransom amount is stated in the note.

The message also discourages victims from turning to file recovery services, describing them as "either scammers or middlemen" who will only result in paying more.

BAVACAI ransomware overview

BAVACAI belongs to the MedusaLocker family, a ransomware group primarily known for targeting businesses and corporate networks. Beyond encrypting files, MedusaLocker variants typically steal data before the encryption phase, using the threat of public exposure as additional leverage against victims who might otherwise restore from backups and ignore the ransom demand.

In general, files encrypted by ransomware cannot be recovered without the attacker's decryption key. The rare exceptions involve ransomware with serious coding flaws, but this cannot be relied upon. Maintaining offline backups - stored on a device that is not connected to the infected network - remains the most reliable way to recover data after an attack.

Paying the ransom is strongly discouraged. Cybercriminals frequently accept payment and send nothing in return. Even when they do provide a tool, there is no guarantee it will work correctly. We strongly advise against paying.

Removing BAVACAI from the system is important to stop further encryption and prevent potential spread to other machines on the same network. That said, removal alone does not restore already-locked files. Recovery depends on whether a clean backup existed before the infection occurred.

Ransomware in general

The core purpose of ransomware is to extort money from victims by locking their files and demanding payment for a decryption tool. Our team has analyzed thousands of ransomware programs. They largely follow the same pattern, though they differ in the symmetric or asymmetric encryption algorithms they use and the ransom amounts they demand.

Additional ransomware examples are BARADAI, Rex, and KRYBIT.

How did ransomware infect my computer?

As a MedusaLocker variant, BAVACAI is likely targeted at corporate environments. Attackers in this family are known to exploit exposed RDP services, using brute force techniques to gain initial access with weak or reused credentials. Once inside the network, they move laterally across connected systems before deploying the ransomware and exfiltrating data.

More broadly, ransomware reaches victims through phishing emails with malicious attachments or links, trojans that silently download additional malware, and Microsoft Office documents with malicious macros. Malicious files are frequently disguised as PDFs, spreadsheets, archives, or standard-looking installers.

Pirated software and illegal activation tools (cracks) are also common delivery vectors, as are fake software updates and untrustworthy third-party download sites. Keeping software up to date and avoiding unofficial sources significantly reduces the risk of infection.

How to protect yourself from ransomware infections?

Be cautious when opening emails from unknown senders, and avoid clicking unexpected links or downloading attachments you did not request. Download software only from official websites and developer pages. Always use legitimate channels to activate or update programs, and keep a reputable antivirus tool installed and up to date.

If your computer is already infected with BAVACAI, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate this ransomware.

Screenshot of BAVACAI's ransom note ("WHATS_HAPPEND.txt"):

Text presented in this ransom note:

DON'T PANIC!!! YOUR FILES ARE PERFECT AND SAFE!
We've found flaws in your security system and gained access to your internal corporate network. Your files were encrypted, and we can help you decrypt them and fix any existing security flaws.

We've also retrieved files from your servers, which will be published in 72 hours if you don't contact us.

Our contact information: qtox - [qTox ID]
e-mail: nhuvgh@outlook.com
our tor fileserver with your files - [.onion URL]

Your ID:
[victim ID]

Please do not use file recovery services. They are either scammers or middlemen. In both cases, you will simply pay more.

Screenshot of BAVACAI ransomware's data leaking site:

BAVACAI 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:

By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by RCS LT, the parent company of PCRisk.com.

Video suggesting what steps should be taken in case of a ransomware infection:

Quick menu:

• What is BAVACAI 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.

Reporting ransomware to authorities:

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?

Ransomware is typically spread through disguised files that look harmless but run malicious code when opened. Common delivery routes include phishing emails, trojans, pirated software, fake software updates, illegal activation tools, and compromised websites. Corporate environments can also be targeted directly via brute force attacks on remote access services such as RDP.

How to open ".BAVACAI" files?

Files with the .BAVACAI extension have been locked by ransomware and cannot be opened in any way until they are decrypted with the correct key.

Where should I look for free decryption tools for BAVACAI ransomware?

If you've been affected by ransomware, 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 decryption services. In most cases, recovering encrypted files without the attacker's tool is not possible, unless the ransomware itself has significant flaws. Third-party paid decryption offers are typically scams or middlemen who take a fee and pass the payment along to the criminals anyway.

Will Combo Cleaner help me remove BAVACAI ransomware?

Combo Cleaner can detect and remove an active BAVACAI infection from your system. It is worth noting that while removal stops the ransomware from causing further damage, it does not decrypt files that have already been locked. Recovering those files requires a decryption key, not an antivirus scan.