How to uninstall Zobm ransomware from the system

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

Zobm ransomware removal instructions

What is Zobm?

Discovered by Amigo-A, Zobm ransomware is a part of the Djvu family of ransomware-type malware. Like most programs of this type, it encrypts (locks) data, creates a ransom message, and adds its extension to each encrypted file. Zobm creates the "_readme.txt" file and appends the ".zobm" extension. For example, "1.jpg" becomes "1.jpg.zobm", and so on.

The "_readme.txt" file (ransom message) states that the only way for victims of Zobm to decrypt their files is to purchase a decryption tool and unique key. Instructions about how to make payment will be provided after sending an email to cyber criminals at or with a personal ID. The cost of decryption software and key is $980, however, victims who make contact within 72 hours of encryption will receive a 50% discount. I.e., victims are encouraged to contact these criminals immediately. Unfortunately, only Zobm's developers have tools that can decrypt files compromised by this ransomware. Note that cyber criminals (ransomware developers) can never be trusted - they often send no decryption tools or keys, even if ransoms are paid. Typically, the only way to recover files without being scammed is to restore them from a backup. Uninstalling ransomware from the system simply prevents it from causing further encryption - all encrypted files remain encrypted.

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

Zobm decrypt instructions

Generally, ransomware encrypts data and creates or displays a ransom message that contains instructions about how to pay the ransom. Main differences are usually cost of decryption software and key, and cryptographic algorithm (symmetric or asymmetric) used to encrypt files. In any case, most victims cannot decrypt their files without tools held only by the cyber criminals who designed the ransomware. It might be possible only in rare cases when the software is not complete, contains bugs/flaws, etc. Victims have just two options: to pay the ransom (not advised) and hope that cyber criminals will send the tools, or restore files from an existing data backup. Therefore, always have data backed up and keep it on a remote server (such as Cloud) or unplugged storage device. Some examples of other ransomware programs are Deuce, 2048, and DeathRansom.

How did ransomware infect my computer?

Typically, ransomware and other malware is distributed through spam campaigns, Trojans, untrustworthy software download channels, unofficial activation ('cracking') tools and fake software updaters. Spam campaigns/emails are used to infect systems through files that are attached to them. If opened, these files install malware. Examples of files often used to proliferate these programs are MS Office or PDF documents, archive files such as ZIP, RAR, JavaScript files, executable files (.exe), and so on. Trojans are malicious programs that cause chain infections. I.e., if the system is infected with a Trojan, it is very likely that this program will install other high-risk malware. Untrustworthy software download sources such as freeware download websites, free file hosting pages, unofficial sites, various Peer-to-Peer networks (like eMule, torrent clients) are often used to disguise malicious files as legitimate and harmless. When people download and open them, however, they install malicious software. Unofficial software activation tools are programs that supposedly bypass activation of paid/licensed software, however, they are commonly designed by cyber criminals who seek to proliferate malicious programs. Therefore, people who use these tools risk installation of malware. Fake software updating tools usually infect systems by exploiting bugs/flaws of outdated software that is installed on the operating system, or by installing malicious programs rather than updates.


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.

Threat Summary:
Name Zobm virus
Threat Type Ransomware, Crypto Virus, Files locker.
Detection Names AVG (FileRepMalware), BitDefender (Trojan.GenericKD.32748008), ESET-NOD32 (A Variant Of Win32/Kryptik.GYTM), Kaspersky (, Full List (VirusTotal)
Encrypted Files Extension .zobm
Ransom Demanding Message _readme.txt
Ransom Amount $980/$490
Cyber Criminal Contact,
Additional Information This malware is designed to show a fake Windows Update window and modify the Windows "hosts" file to prevent users from accessing cyber security websites (more information below).
Distribution methods Infected email attachments (macros), torrent websites, malicious ads, unofficial activation and updating tools.
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

Never trust irrelevant emails that contain attachments and are received from unknown, suspicious addresses. They are often disguised as official, important, and so on, however, once the attached file is opened, it installs malware. Do not download or install software using third party downloaders, installers, from unofficial pages, and other similar sources. The safest way to download software is using official and trustworthy websites. All installed programs should be updated using tools designed and provided by official software developers. Third party, fake updaters often infect systems and proliferate malicious programs. The same applies to unofficial activation tools, which supposedly activate licensed software free of charge. It is illegal to use such tools. Have a reputable antivirus or anti-spyware suite installed and scan the operating system with it regularly. If your computer is already infected with Zobm, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in Zobm ransomware text file ("_readme.txt"):


Don't worry, you can return all your files!
All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool:
Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that's price for you is $490.
Please note that you'll never restore your data without payment.
Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours.

To get this software you need write on our e-mail:

Reserve e-mail address to contact us:
Your personal ID:

Screenshot of files encrypted by Zobm (".zobm" extension):

Files encrypted by Zobm

Screenshot of fake Windows update pop-up displayed during the encryption:

Fake Windows pop-up displayed by Zobm during the encryption

IMPORTANT NOTE! - As well as encrypting data, ransomware-type infections from the Djvu malware family also add a number of entries to the Windows "hosts" file. The entries contain URLs of various websites, most of which are related to malware removal. This is done to prevent users from accessing malware security websites and seeking help. Our website ( is also on the list. Removing these entries, however, is simple - you can find detailed instructions in this article (note that, although the steps are shown in the Windows 10 environment, the process is virtually identical on all versions of the Microsoft Windows operating system).

Screenshot of websites added to Windows hosts file:

Tro Ransomware adding websites to Windows Hosts file

There are currently two versions of Djvu ransomware infections: old and new. The old versions were designed to encrypt data by using a hard-coded "offline key" whenever the infected machine had no internet connection or the server was timing out/not responding. Therefore, some victims were able to decrypt data using a tool developed by cyber security researcher, Michael Gillespie, however, since the encryption mechanism has been slightly changed (hence the new version, released in August, 2019), the decrypter no longer works and it is no longer supported. If your data has been encrypted by an older version, you might be able to restore it with the another tool developed by Emsisoft and Michael Gillespie. It supports a total of 148 Djvu variants and you can find more information, as well as download link and decryption instructions on Emsisoft's official web page.

Screenshot of Djvu decryption tool by Emsisoft and Michael Gillespie:

Djvu ransomware decrypter by Michael Gillespie and Emsisoft

Additionally, Emsisoft is now providing a service that allows data decryption (again, only if it was encrypted by Djvu variants released before August, 2019) for those victims who have copies of the original and compromised file before and after the encryption. Victims simply upload a pair of original and encrypted file to Emsisoft's Djvu decryption page and download the aforementioned decryption tool (the download link will be provided after uploading files). Note that the file processing may take some time, so be patient. Note that the system must have an internet connection during the entire decryption process, otherwise it will fail.

Screenshot of Emsisoft Djvu decryption service page:

Djvu ransomware decryption service by Emsisoft

Zobm ransomware removal:

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Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the Zobm virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the Zobm ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining Zobm ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of Zobm are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by Zobm, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as Zobm ransomware.

Note that Windows 10 Fall Creators Update includes a "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default, this feature automatically protects files stored in the Documents, Pictures, Videos, Music, Favorites, and Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here is more information on how to get this update and add an additional protection layer from ransomware infections.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove Zobm ransomware:

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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Zobm virus QR code
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