How to remove MZ434376 ransomware from your operating system

Also Known As: MZ434376 virus
Distribution: Low
Damage level: Severe

MZ434376 ransomware removal instructions

What is MZ434376?

Discovered by GrujaRS, MZ434376 is a malicious program belonging to the KesLan ransomware family. It is designed to encrypt data and then demand ransom payments for decryption. During the encryption process, all compromised files are renamed with the ".MZ434376" extension. For example, "1.jpg" appears as "1.jpg.MZ434376" following encryption. After this process is complete, the ransomware stores an HTML application called "Beni_Oku!!!.hta" on the desktop. This file contains the ransom message in Turkish.

According to a rough translation, the text presented in "Beni_Oku!!!.hta" ("Read_Me!!!") states that all of the victim's data has been encrypted. Important files such as documents, photos, databases and similar have been encrypted, and if users wish to recover them, they must purchase decryption tools/software from the developers of MZ434376 ransomware. To receive further instructions, they are urged to contact the cyber criminals via the email address provided. Should no response arrive within 24 hours, users are instructed to use an alternative address. The paragraph entitled "What should I do???" clarifies that the affected files are not damaged, but rather encrypted with the M-M encryption algorithm. Therefore, it is apparently possible to restore them. The message states, however, that the only way to do so is to purchase unique decryption tools/software from the malware's developers. Users are warned against manual decryption with third party software, as this will lead to permanent data loss. The next paragraph reiterates that to decrypt the files, decryption tools/software must be purchased from the criminals behind the infection. The size of the ransom is stated to be 300 USD in the Bitcoin cryptocurrency. A different paragraph lists links, which lead to instructions about how to and from where to obtain Bitcoins. After payment is made, victims are promised that automatic decryption tools will be sent via an email message. The next section concerns decryption guarantees. The developers offer to decrypt up to two files free of charge. The test files are to be sent using a file-sharing service and archived using the WinRAR file archiving program. These files cannot exceed 1 MB (prior to being archived) and contain no important information (e.g. databases, backups, large excel sheets). The penultimate paragraph consists of warnings. Victims are warned once more that decryption with third party software will damage the encrypted files irreparably, and changing the filenames can lead to the same outcome. Users are informed that they have two days to pay the ransom, otherwise decryption will no longer be viable. The last paragraph contains a unique key, which is encrypted with the AES-256 encryption algorithm. Since this key is necessary for decryption, victims are instructed not to tamper with it in any way (e.g. rewrite or delete it, etc.). Unfortunately, in most cases of these infections, decryption is impossible without the involvement of the ransomware developers, unless (in rare cases) the malware in question is still in development and/or has certain flaws/bugs. Regardless, you are strongly advised against meeting the demands of cyber criminals. These individuals cannot be trusted and often, despite paying, users do not received the promised decryption tools/software. Therefore, their data remains encrypted and useless. To prevent MZ434376 from further encryption, it must be removed from the operating system, however, this will not restore already affected files. Recovering data from a backup might be a solution, if one was made before the infection and was stored separately

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

MZ434376 decrypt instructions (Beni_Oku!!!.hta)

Deniz_KiziMkos, and RedRum are some examples of other malicious programs in this category. All ransomware encrypts data and demands payment for decryption. Crucial differences include cryptographic algorithm they use (symmetric or asymmetric) and ransom size. To ensure data safety, keep backups on remote servers and/or unplugged storage devices. Ideally, multiple backup copies should be stored in several different locations.

How did ransomware infect my computer?

Ransomware and other malware mainly proliferates through spam campaigns, trojans, untrustworthy download channels, illegal activation ("cracking") tools and fake updaters. Large scale spam campaigns are used to send deceptive emails containing infectious files (or links leading to them). These messages are typically presented as "official", "important", "priority" and similarly urgent mail. The attachments come in various formats (e.g. archive and executable files, PDF and Microsoft Office documents, JavaScript and so on). When these files are opened, it initiates the infection. Therefore, opening a dangerous file triggers it to begin downloading/installing malicious software. Trojans are a type of malware designed to cause chain infections. Untrustworthy download channels such as unofficial and free file-hosting websites, P2P sharing networks (BitTorrent, eMule, Gnutella, etc.) and other third party downloaders can offer malicious content for downloading (e.g. disguised as normal programs and/or bundled with them). Rather than activating licensed products, illegal activation tools ("cracks") can download/install malware. Illegitimate updaters infect systems by misusing the flaws of outdated software and/or simply by installing malware rather than the promised updates.

Threat Summary:
Name MZ434376 virus
Threat Type Ransomware, Crypto Virus, Files locker.
Encrypted Files Extension .MZ434376
Ransom Demanding Message Beni_Oku!!!.hta
Ransom Amount 300 USD in Bitcoins.
Cyber Criminal Contact and
Detection Names Avast (Win32:Malware-gen), BitDefender (Gen:Trojan.Heur.V00br457frfi), ESET-NOD32 (A Variant Of Win32/Filecoder.NZK), Kaspersky (HEUR:Trojan-Ransom.Win32.CryFile.gen), 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)

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How to protect yourself from ransomware infections

Suspicious/Irrelevant emails should not be opened. All attachments and links found in suspect messages must never be opened, as they are the origin of a potential infection. You are advised to use only official and verified download channels. Programs should be activated and updated with tools/functions provided by genuine developers and not with those acquired from third parties. Have a reputable anti-virus/anti-spyware suite installed and kept up-to-date. Use this software for regular system scans and removal of detected threats/issues. If your computer is already infected with MZ434376, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in MZ434376 ransomware HTML application ("Beni_Oku!!!.hta"):


Merhaba! T¸m belgeleriniz, fotograflariniz, veritabanlariniz ve diger ˆnemli dosyalariniz SIFRELENDI! GerÁekten dosyalarini geri y¸klemek istiyor musun?
Eger istiyorsan, verilerinizin kilidini aÁmak iÁin size ˆzel olan desifre yazilimi satin almalisiniz!
E-postamiza yazin - eger 24 saat iÁinde cevap alamazsaniz, ek e-posta adresimize yazin -
T¸m dosyalarinizin sifresini nasil Áˆzeceginize dair size tam bir talimat gˆnderecegiz.


÷ncelikle dosyalariniz HASARLI DEGIL! Dosyalariniz M-M sifreleme algoritmasiyla degistirilmis ve sifrelenmistir. Bu degisiklik geri dˆn¸s¸ml¸d¸r. Dosyalarinizin sifresini Áˆzmenin tek yolu size ˆzel olan desifre aracini satin almaktir. Herhangi bir girisimde bulunmak dosyalarinizi dˆn¸lmez sekilde bozar ve ¸Á¸nc¸ taraf yazilimiyla geri y¸klemeye kalkismak dosyalariniz iÁin ˆl¸mc¸l olacaktir.


Sifreyi Áˆzmek iÁin size ˆzel olan desifre aracimizi satin almalisiniz, bunu zaten dedik.
ve desifre aracinin fiyati 300 dolar, ˆdemeyi bitcoin yolu ile yapacaksiniz ve ˆdeme iÁin bize ulasmalisiniz. ÷deme yapildiktan sonra size ˆzel olan desifre aracini size e-posta yoluyla gˆnderecegiz. desifre aracini masa¸st¸ne atip Áalistirmak yeterlidir, sonra otomatik olarak t¸m dosyalariniz eski haline dˆnecektir.


Garanti olarak ¸cretsiz sifre Áˆzme!
Hizmetimize inanmiyorsaniz ve bir kanit gˆrmek istiyorsaniz, bize test hakkinda soru sorabilirsiniz.
sifre Áˆzme iÁin. Bize 2 adete kadar sifrelenmis dosya gˆnderirsiniz. Test iÁin dosya gˆndermek iÁin dosya paylasim servisini ve Win-Rar kullanin. Dosyalar 1 MB"den k¸Á¸k olmalidir (arsivlenmemis) ve Dosyalar ˆnemli olmamalidir! Bize veritabanlarini, yedekleri ve b¸y¸k excelleri gˆndermeyin. dosyalar vb. Sifreyi Áˆzer ve sifresi Áˆz¸lm¸s dosyalarinizi bir kanit olarak geri gˆndeririz!


Bitcoin"lerin iki basit yolu var:
Link1: hxxps://
Link2: hxxps://
Bu linkler"deki bilgiyi dikkatlice okuyun, Á¸nk¸ b¸y¸k miktarlarda bile satin almaniz gerekebilir.

Not: T¸rkÁe kaynak iÁin Áeviri kullanin.

!!! DIKKAT !!!

!!! 2 g¸n iÁinde ˆdeme yapmazsaniz sonsuza kadar dosyalarinizi kurtaramazsiniz.
!!! Sifrelenmis dosyalari yeniden adlandirmayin.
!!! ‹Á¸nc¸ taraf yazilimi kullanarak verilerinizin sifresini Áˆzmeye Áalismayin, bu kalici veri kaybina neden olabilir.
!!! Dosyalarinizin ¸Á¸nc¸ taraflarin yardimi ile Áˆz¸lmesi, fiyatlarin artmasina neden olabilir ve sakin kimseye g¸venmeyin kˆpeginize bile.


Sakin bu anahtari degistirmeyin sifre Áˆzme araci iÁin bu anahtar gerekli eger dosyalariniz umrunuzda degilse kurcaliyabilirsiniz.
ve unutmayinki bu anahtar AES-256 sifreleme sistemi ile sifrelenmistir.



The appearance of MZ434376 ransomware ransom message (GIF):

MZ434376 ransomware ransom note appearance (GIF)

Screenshot of files encrypted by MZ434376 (".MZ434376" extension):

Files encrypted by MZ434376 ransomware (.MZ434376 extension)

MZ434376 ransomware removal:

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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 cyber crime and potentially assist in prosecution of the attackers. Here's a list of authorities where you should report a ransomware attack. For the complete list of local cyber security 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):

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: Disconnecting computer from the Internet (step 1)

Click the "Change adapter settings" option in the upper-left corner of the window: Disconnecting computer from the Internet (step 2)

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". Disconnecting computer from the Internet (step 3)

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": Ejecting external storage devices

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).

Identify ransomware-type infection (step 1)

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).

Identify ransomware-type infection (step 2)

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).

Identify ransomware-type infection (step 3)

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):

Identify ransomware-type infection (step 4)

Example 2 (.iso [Phobos] ransomware):

Identify ransomware-type infection (step 5)

If your data happens to be encrypted by a ransomware that is not supported by ID Ransomware, you can always try searching the internet by using certain keywords (for example, ransom message title, file extension, provided contact emails, cryptowallet 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, cyber criminals 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.

Searching for ransomware decryption tools in website

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 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.

Recuva data recovery tool wizard

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 hundreds 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:

Recuva data recovery tool scan time

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:

Recuva data recovery tool recovering 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 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 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 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 icon in the taskbar

Click the OneDrive cloud icon to open the OneDrive menu. While in this menu, you can customize your file backup settings.

Select Help & Settings and click Settings

Click Help & Settings and then select Settings from the drop-down menu.

Select the Backup tab and click Manage backup

Go to the Backup tab and click Manage backup.

Select folders to backup and click Start backup

In this menu, you can choose to backup the Desktop and all of the file 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.

Select a file manually and copy it

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.

Paste the copied file in the OneDrive folder to create a backup

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.

File statuses in OneDrive folder

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 on only on OneDrive. The sync icon indicates that the file is currently syncing.

Click Help & Settings and click View Online

To access files only located on OneDrive online, go to the Help & Settings drop-down menu and select View online.

Click the Settings cog and click Options

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 guides 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.

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About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

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Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

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