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Remove Zobm virus and decrypt .zobm ransomware files

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Being hit by the .zobm file variant of the Djvu/STOP ransomware is a messy experience because of data inaccessibility and the looming Bitcoin ransom demand.


  1. What is the Zobm ransomware?
  2. Zobm ransomware automated removal and data recovery
  3. Zobm ransomware manual removal and file recovery
  4. Ransomware Prevention Tips


What is the Zobm ransomware??

With some ransomware campaigns going to extremes with their quick ups and dramatic downs, the Djvu/STOP family has been consistently prolific over the time frame of about a year. It is constantly generating new knockoffs that act in very much the same way as its precursors, except that the extensions appended to victims’ encrypted files tend to switch with each iteration. One of the latest versions uses the .zobm string to blemish hostage data items while creating the invariable ransom note named _readme.txt. This ostensible dullness of the lineage under scrutiny doesn’t mean that it’s hardly changing at the code level. Most Djvu ransomware personas released before August 2019 had a bug in their encryption routine, which gave researchers from Emsisoft the green light to create a viable free decryption tool.

However, all spinoffs launched afterwards, including the Zobm build, implement the crypto in a more efficient way and therefore cannot be cracked unless the file scrambling process is executed using an offline encryption key. This isn’t a common situation, though. It only occurs when the Internet connection on an infected host drops right after the contamination for some reason, or in case the malicious program cannot query its C2 server for a unique cryptographic key.

This ransomware version uses .zobm file extension and _readme.txt ransom note

As soon as a random-named Zobm ransomware binary is introduced to a host environment, the infection runs a series of commands to disable the Volume Snapshot Service (VSS) and delete Shadow Copies of the victim’s data. This technique is one of the strongholds of further extortion because it prevents the user from restoring their files via a backup feature built into the Windows operating system. Then, the virus fires up a covert scan to find all the information that’s likely to matter to the user. The logic of this process involves a predefined list of the most popular file formats to look for.

Once the scan is completed, Zobm tries to establish a connection with its server to receive a public encryption key required for the data mutilation process. The two different scenarios (successful versus failed server communication) are described above. The ransomware starts the encryption routine either way, leveraging asymmetric RSA cipher. This is a resource-heavy thing, so the computer will probably slow down along the way. To veil this hideous activity, the Zobm virus displays a phony Windows update popup message telling the user not to turn off the computer until the “update” is through.

Zobm victims discover _readme.txt ransom document in every folder with encrypted data

The unauthorized data tweaking, when finished, entails the victim’s inability to access their important files, including Office documents and spreadsheets, pictures, videos, PDF files, and other objects most people store on their computers. Every hostage file is easy to identify as such: it gets the .zobm extension concatenated to its original name. Here’s an illustration of the change: a file Seaside.bmp is renamed to Seaside.bmp.zobm. Some victims hope they can revert the modifications by deleting the redundant tail, but this is certainly wishful thinking due to a much more drastic impact targeting the deep file structure rather than just the filenames.

Every folder with encrypted entities in it will also be complemented with a ransom note, which is sort of a manual that explains the basics of what’s going on and includes preliminary instructions to start the decryption as the attackers view it. In the case of the Zobm ransomware, this is a document with the self-explanatory name “_readme.txt”. According to it, the ransom amounts to $980. If the infected user contacts the attackers within the first three days, they will allegedly get 50% off, so the price will be $490. The ransom is payable in Bitcoin cryptocurrency.
The crooks even provide a link to an online video review of the decryptor they “upsell”. In order to learn how to buy this software, the victim is supposed to send their personal ID (provided in the ransom note) to the perpetrators at restorealldata@firemail.cc or gorentos@bitmessage.ch. The former email address, by the way, has been added to the Djvu/STOP distributors’ contacts list just recently. In response to the message, the villains will send back the BTC address to submit the ransom. Whether or not they will actually make the decrypt tool available after the payment is unknown.
The Zobm ransomware is a spam-borne threat, for the most part. It mainly reaches new systems via misleading emails disguised as invoices, resumes, job offers, failed delivery notices, and other subjects that tend to attract recipients’ attention. The attached Word file asks the user to enable macros so that its contents can be rendered properly. If the would-be victim is imprudent to follow that prompt, a VBA subroutine will be triggered to pull in the ransomware payload and run on the machine. With that said, avoiding the Zobm variant of Djvu ransomware is a matter of exercising caution with suspicious email attachments. If the infection is already inside, the following steps are worth trying before making any further decisions regarding file restoration.

Zobm ransomware automated removal and data recovery

Owing to an up-to-date database of malware signatures and intelligent behavioral detection, the recommended software can quickly locate the infection, eradicate it and remediate all harmful changes. So go ahead and do the following:

1. Download and install the antimalware tool. Open the solution and have it check your PC for PUPs and other types of malicious software by clicking the Start Computer Scan button

Download ransomware infections remover

2. Rest assured the scan report will list all items that may harm your operating system. Select the detected entries and click Fix Threats to get the troubleshooting completed.

Data recovery toolkit to the rescue

Some strains of ransomware are known to delete the original files after the encryption routine has been completed. As hostile as this activity appears, it can play into your hands. There are applications designed to revive the information that was obliterated because of malfunctioning hardware or due to accidental removal. The tool called Data Recovery Pro by ParetoLogic features this type of capability therefore it can be applied in ransom attack scenarios to at least get the most important files back. So download and install the program, run a scan and let it do its job.

Download Data Recovery Pro

Data Recovery Pro


Zobm ransomware manual removal and file recovery

Some ransomware strains terminate themselves after completing the encryption job on a computer, but some don’t. Furthermore, the Zobm virus may prevent victims from using popular antimalware tools in order to stay on board for as long as possible. Under the circumstances, it may be necessary to utilize the Safe Mode with Networking or System Restore functionality.

Remove the Zobm ransomware using Safe Mode with Networking

Remove the Zobm ransomware using Safe Mode with Networking

Boot into Safe Mode with Networking. The method to do it depends on the version of the infected operating system. Follow the instructions below for your OS build.

  • Restart the machine. When the system begins loading back up, keep pressing the F8 key with short intervals. The Windows Advanced Options Menu (Advanced Boot Options) screen will appear.Boot into Safe Mode with Networking on Windows Vista and 7
  • Use arrow keys to select Safe Mode with Networking and hit Enter. Log on with the user account infected by the ransomware.
  • Click on the Search icon next to the Start menu button. Type msconfig in the search field and select the System Configuration option in the results. Go to the Boot tab in the upper part of the GUI.Boot options on Windows 8, 8.1 and 10
  • Under Boot options, select Safe boot and click the Apply button. A prompt will appear to reboot the computer so that the changes take effect. Select the Restart option and wait for the system to load into Safe Mode. Again, log on with the ransomware-stricken user account.

In Safe Mode, the ransom Trojan won’t keep security software from running or otherwise thwart troubleshooting. Open your preferred web browser, download and install an antimalware tool of choice and start a full system scan. Have all the detected ransomware components removed in a hassle-free way.

Get rid of the Zobm using System Restore

Get rid of the Zobm using System Restore

System Restore enables Windows users to roll back all changes made to the OS since the latest restore point creation time. This feature can help eliminate the most persistent ransomware. Before going this route, though, make sure System Restore had been enabled prior to the breach, otherwise the method will be inefficient.

  • Open Windows Advanced Options Menu as described in the previous section: hit F8 repeatedly when the PC is starting up. Use arrow keys to highlight the Safe Mode with Command Prompt entry. Hit Enter.Safe Mode with Command Prompt
  • In the Command Prompt window, type cd restore and hit Entercd restore command
  • Type rstrui.exe in the new command line and press EnterType rstrui.exe command
  • When the System Restore screen pops up, click Next, select a restore point that predates the contamination, and use the application’s controls to roll back the system to this earlier state.System Restore window

Be advised that even after the ransomware is removed, files will still be encrypted and inaccessible. The malicious code cleanup part, however, is important because it keeps a relapse of the infection from occurring further on and eliminates all opportunistic malware.

Ways of non-ransom recovery of .zobm files encrypted by Djvu/STOP strain

Cracking the crypto used by this ransom Trojan is more of a science fiction thing rather than an attainable prospect for the masses. This is why the troubleshooting in predicaments of this sort is a matter of two approaches: one is to pay the ransom, which isn’t an option for many victims; and the other is to apply instruments that take advantage of the ransomware’s possible weaknesses. If the latter is your pick, the advice below is a must-try.

Backups can make your day

Backups can make your day

Not only are you a lucky person in case you’ve been backing up your most important files, but you’re also a wise and prudent user. This isn’t necessarily a resource-heavy activity these days – in fact, some providers of online services are allocating a sufficient size of cloud storage space for free so that every customer can easily upload their critical data without paying a penny. Having removed the ransomware, therefore, all you have to do is download your stuff from the remote server or transfer it all from an external piece of hardware if that’s the case.

Restore previous versions of encrypted files

Restore previous versions of encrypted files

A positive upshot of using this technique depends on whether or not the ransomware has erased the Volume Shadow Copies of the files on your PC. This is a Windows feature that automatically makes and keeps the backups of data elements on the hard drive as long as System Restore is enabled. The cryptoware in question is programmed to switch off the Volume Shadow Copy Service (VSS), but it has reportedly failed to in some cases.

Checking one’s options regarding this workaround is doable in two ways: through the Properties menu of each file or by means of the remarkable open-source tool called Shadow Explorer. We recommend the software-based way because it’s automated, hence faster and easier. Just install the app and use its intuitive controls to get previous versions of the encrypted objects reinstated.
Shadow Explorer

Alternatively, you can leverage the Previous Versions feature, which is native to Windows operating system. This method is more cumbersome that the use of ShadowExplorer, but it can help restore the most important individual files on condition that the ransomware failed to disable the Volume Snapshot Service on the computer. Right-click on a file of choice and select Properties. Then, go to the Previous Versions tab as illustrated below.
Previous Versions

Go ahead and pick the file’s latest backup version on the list. Use the Copy or Restore buttons to reinstate this object to a new path or to its original folder, respectively.


Ransomware Prevention Tips

To avoid Zobm ransomware and other file-encrypting infections in the future, follow several simple recommendations:

  • Toggle your email provider’s anti-spam settings to filter out all the potentially harmful incoming messages. Raising the bar beyond the default protection is an important countermeasure for ransom Trojans

  • Define specific file extension restrictions in your email system. Make sure that attachments with the following extensions are blacklisted: .js
  • .vbs
  • .docm
  • .hta
  • .exe
  • .cmd
  • .scr
  • and .bat. Also
  • treat ZIP archives in received messages with extreme caution

  • Rename the vssadmin.exe process so that ransomware is unable to obliterate all Shadow Volume Copies of your files in one shot

  • Keep your Firewall active at all times. It can prevent crypto ransomware from communicating with its C&C server. This way
  • the threat won’t be able to obtain cryptographic keys and lock your files

  • Back up your files regularly
  • at least the most important ones. This recommendation is self-explanatory. A ransomware attack isn’t an issue as long as you keep unaffected copies of your data in a safe place

  • Use an effective antimalware suite. There are security tools that identify ransomware-specific behavior and block the infection before it can do any harm.
These techniques are certainly not a cure-all, but they will add an extra layer of ransomware protection to your security setup.

Revise your security status

Post-factum assessment of the accuracy component in malware removal scenarios is a great habit that prevents the comeback of harmful code or replication of its unattended fractions. Make sure you are good to go by running an additional safety checkup. Another benefit of using the antimalware tool is that it will keep ransomware threats from intruding on your computer further on.

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