ZNSM ransomware virus attacks files on the system
Contents
ZNSM ransomware virus encrypts files on Windows-running computers at a rather fast pace, making it relatively more destructive and should be avoided at all costs. It is a confirmed malware variant coming from the STOP/DJVU ransomware family. Once this virus successfully gains entry into a computer, the next thing it does is encryption of files, one after another. In the process, diverse files are damaged irreversibly, including documents, videos, and pictures. Afterward, it will add .znsm extension to each filename, which also serves as an indicator that the file was locked. The virus also drops ransom notes called _readme.txt in each folder.
To illustrate this, files that the user has previously saved in the computer with names such as 1.jpg, 2.png, or 3.jpeg will become 1.jpg.znsm, 2.png.znsm and 3.jpeg.znsm. There will be no way to open or edit these files, no matter what software the user attempts to use.
On top of that, this ransomware travels together with information-stealing Trojans known as Vidar, Azorult or RedLine.
Ransom note demands money for data decryption
What _readme.txt notification does is to call the victim’s attention to what has happened and why it has become necessary for the victim to cooperate with those behind the attack. The note will suggest that solution could be available if the victim can reach out via these emails; support@freshmail.top, datarestorehelp@airmail.cc.
The ransom note doesn’t contain information on how the victim should pay the ransom – the criminals only reveal this information for those who contact them via email. After doing so, the victim will receive a response demanding a fee of $980 that must be paid in Bitcoin or another cryptocurrency.
To make the victim pay without delay, they may promise to slash the ransom fee by 50%, thus bringing it down to $490. But with the condition that it must be paid within 72 hours. If the victim fails to meet the strict deadline, the offer becomes nullified. In other words, the perpetrators will only accept the full ransom fee once 3 days pass. The reason why the criminals only accept cryptocurrency is based on the fact that such money transfer is nearly untraceable and cannot be used to reveal the attackers’ identities.
Unfortunately for victims, there is no guarantee that encrypted files will be restored even after complying with their demands. Cybercriminals usually cut off communication with the victim once they receive ransom payment or might decide to forward ineffective decryption tools. Hence, we arrived at the conclusion that victims should never pay a ransom. The same idea is expressed by law enforcement agencies like FBI. Other factors we considered are listed below:
- Most existing laws are against ransom payments.
- Cybercriminals are encouraged when they receive ransom payments.
- Victims that pay ransom are further attacked in the future.
- When huge sums of money are paid to cybercriminals, it enables them to expand their illegal activities, thereby putting others at risk.
- If all victims refused to pay the ransom, cybercriminals will be forced to stop further attacks since it’s no longer lucrative.
If you have found yourself in an unfortunate situation where all of your files were encrypted, we advise you to read this article carefully and then follow instructions provided below it. These instructions will help you to remove ZNSM ransomware virus from your computer. If you’re undecided on which antivirus software to go for, we highly recommend INTEGO Antivirus that we have recently reviewed on our website. On top of that, downloading RESTORO might be an option, since this tool is capable of reversing malware damage on Windows OS files.
Ransomware Summary
| Name | ZNSM Ransomware Virus |
| Type | Ransomware; Crypto-malware; Virtual Extortion Virus |
| Family | STOP/DJVU |
| Encryption type | RSA 2048 + Salsa20 |
| Previous versions | JYPO, KIFR, KIOP, KITZ, BOZA, BOTY, COZA (find full list here) |
| Version | 623rd |
| Extension | .znsm |
| Cybercriminal emails | support@freshmail.top, datarestorehelp@airmail.cc |
| Additional malware dropped | Azorult or Vidar Trojan |
| Damage | The ransomware uses encryption to maliciously modify all files on the PC and marks their original names with .znsm extension. Ransom notes called as _readme.txt will be dropped in every computer folder. This piece of malware usually drags VIDAR Stealer alongside it and also eliminates VSS from the system. On top of that, it tends to modify Windows HOSTS file to restrict computer user’s access to cybersecurity-related websites online. |
| Ransom note | _readme.txt |
| Ransom demand | $490-$980 in Bitcoin |
| Distribution | Victims often download this ransomware along illegal torrent downloads, cracked software, activators, key generators or tools like KMSPico. |
| Known software cracks to contain this malware | Corel Draw, Tenorshare 4ukey, Adobe Photoshop, Cubase, Adobe Illustrator, Internet Download Manager, Tally, League of Legends. |
| Detection names | Trojan:Win32/Azorult.FW!MTB (Microsoft), Gen:Heur.Mint.Zard.52 (B) (Emsisoft), HEUR:Trojan.Win32.Scarsi.gen (Kaspersky), Gen:Heur.Mint.Zard.52 (BitDefender), Trojan.MalPack.GS (Malwarebytes), ML.Attribute.HighConfidence (Symantec) see all detection name variations on VirusTotal |
| Removal | Remove ransomware and related malware from your PC using trustworthy software like INTEGO Antivirus. To repair virus damage on Windows OS files, download and try RESTORO (secure download link). |
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How cybercriminals spread malware
Cybercriminals behind this notorious ransomware strain apparently use the same methods to spread ZNSM virus as for previous STOP/DJVU versions. The primary method is to upload fake software installation files to websites claiming to provide software cracks, and the secondary method is based on malicious email spam. We have overviewed these methods below.
Sometimes, cybercriminals forward unsolicited emails with attachments to lots of random addresses. While at it, they will impersonate representatives of globally recognized brands like Amazon, FedEx, or eBay, among others. Since their target is to get their target audience to open the accompanying attachment, they will give it compelling tags like Order Summary, Invoice, or Tracking Number. If the recipient isn’t careful enough to detect it is a scam and opens the attachment, they end up triggering a ransomware virus attack. For this reason, it is important to be cautious when checking email and avoid any suspicious emails that reach you unexpectedly.
Another common method used for ransomware distribution is based on illegal downloads. All that cybercriminals have to do is set up rogue websites that advertise unlawful downloads, such as software cracks or other copyright-protected content such as movies or desktop wallpapers. Then they simply wait for users to download these malicious files. To avoid detection, such files may come in password-protected archives. To be on the safe side, users should only download software copies and other content legitimately.
Also ransomware viruses can also trigger installation of RATs, otherwise known as remote access Trojans. RATs are used by cybercriminals to steal sensitive personal information like passwords, software login details or credit card information, etc. Such information can later be used to blackmail victim. STOP/DJVU variants are often spotted spreading in tandem with Vidar and Azorult Trojans.
General information on avoiding ransomware attacks
It should be noted that these cybercriminals are only seeking ways they can exploit to fleece their victims. Therefore, they cunningly spread ransomware viruses to many unsuspecting computer owners. The idea is to encrypt their victims’ files and hope it will be significant enough to warrant them seeking reversal, especially when they do not have backups.
However, we recommend installing strong antivirus software on every computer and keeping it active through regular system scanning. Installing a legitimate antivirus with real-time protection is a crucial step toward protecting your computer. Others include buying or downloading only original software contents legitimately and exercising caution when opening emails with attachments (emails/attachments that appear dubious should never be opened).
Cybercriminals know that some people in need of software do not like paying the fees requested by their copyright owners, so they clone the ones in high demand and make them available for download at little or no cost. So they upload such cloned versions to online torrent platforms or enable them to be distributed through P2P sharing networks. The users may assume they’ve saved money, but unbeknownst to them, they’re only exposing their computers to ransomware virus attacks.
Remove ZNSM ransomware virus and decrypt files
You should remove ZNSM ransomware virus as threats like it should never be allowed to linger in any computer for long. So, you’re advised to delete its components using a robust security software and also make use of computer’s Safe Mode with Networking option. For optimal results, you might want to use INTEGO Antivirus because it is tested and trusted by our team.
Once ZNSM virus removal is finalized, here are other things you should do:
- Try downloading RESTORO to repair virus-damaged Windows OS files.
- Change all existing passwords immediately.
- Make use of available backups in restoring lost files.
- Report the incident to relevant local authorities if necessary.
OUR GEEKS RECOMMEND
Our team recommends a two-step rescue plan to remove ransomware and other remaining malware from your computer, plus repair caused virus damage to the system:
STEP 1. REMOVE AUTOMATICALLY WITH ROBUST ANTIVIRUS
STEP 2. REPAIR VIRUS DAMAGE TO YOUR COMPUTER
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ZNSM Ransomware Virus Removal Guidelines
Method 1. Enter Safe Mode with Networking
Step 1. Start Windows in Safe Mode with Networking
Before you try to remove ZNSM Ransomware Virus virus, you must start your computer in Safe Mode with Networking. Below, we provide the easiest ways to boot PC in the said mode, but you can find additional ones in this in-depth tutorial on our website – How to Start Windows in Safe Mode. Also, if you prefer a video version of the tutorial, check our guide How to Start Windows in Safe Mode on Youtube.
Instructions for Windows XP/Vista/7 users
- First of all, turn off your PC. Then press the Power button to start it again and instantly start pressing F8 button on your keyboard repeatedly in 1-second intervals. This launches the Advanced Boot Options menu.
- Use arrow keys on the keyboard to navigate down to Safe Mode with Networking option and press Enter.
Instructions for Windows 8/8.1/10/11 users
- Open Windows Start menu, then press down the Power button. On your keyboard, press down and hold the Shift key, and then select Restart option.
- This will take you to Windows Troubleshoot screen. Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Tip: If you can't find Startup Settings, click See more recovery options.
- In Startup Settings, press the right key between F1-F9 to enter Safe Mode with Networking. In this case, it is the F5 key.
Step 2. Remove files associated with the virus
Now, you can search for and remove ZNSM Ransomware Virus files. It is very hard to identify files and registry keys that belong to the ransomware virus, Besides, malware creators tend to rename and change them repeatedly. Therefore, the easiest way to uninstall such type of a computer virus is to use a reliable security program such as INTEGO Antivirus. For virus damage repair, consider using RESTORO.
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Method 2. Use System Restore
In order to use System Restore, you must have a system restore point, created either manually or automatically.
Step 1. Boot Windows in Safe Mode with Command Prompt
Instructions for Windows XP/Vista/7 users
- Shut down your PC. Start it again by pressing the Power button and instantly start pressing F8 button on your keyboard repeatedly in 1-second intervals. You will see Advanced Boot Options menu.
- Using arrow keys on the keyboard, navigate down to Safe Mode with Command Prompt option and press Enter.
Instructions for Windows 8/8.1/10/11 users
- Launch Windows Start menu, then click the Power button. On your keyboard, press down and hold the Shift key, and then choose Restart option with the mouse cursor.
- This will take you to Windows Troubleshoot screen. Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Tip: If you can't find Startup Settings, click See more recovery options.
- In Startup Settings, press the right key between F1-F9 to enter Safe Mode with Command Prompt. In this case, press F6 key.
Step 2. Start System Restore process
- Wait until system loads and command prompt shows up.
- Type cd restore and press Enter, then type rstrui.exe and press Enter. Or you can just type %systemroot%system32restorerstrui.exe in command prompt and hit Enter.
- This launches System Restore window. Click Next and then choose a System Restore point created in the past. Choose one that was created before ransomware infection.
- Click Yes to begin the system restoration process.
After restoring the system, we recommend scanning the system with antivirus or anti-malware software. In most cases, there won't be any malware remains, but it never hurts to double-check. In addition, we highly recommend checking ransomware prevention guidelines provided by our experts in order to protect your PC against similar viruses in the future.
Alternative software recommendations
Malwarebytes Anti-Malware
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System Mechanic Ultimate Defense
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Decrypt ZNSM files
Fix and open large ZNSM files easily:
It is reported that STOP/DJVU ransomware versions encrypt only the beginning 150 KB of each file to ensure that the virus manages to affect all files on the system. In some cases, the malicious program might skip some files at all. That said, we recommend testing this method on several big (>1GB) files first.
- Create a copy of encrypted file to a separate folder using Copy > Paste commands.
- Now, right-click the created copy and choose Rename. Select the ZNSM extension and delete it. Press Enter to save changes.
- In the prompt asking whether you want to make the changes as file might become unusable, click OK.
- Try opening the file.
STOP/DJVU decryption tool usage guide
STOP/DJVU ransomware versions are grouped into old and new variants. ZNSM Ransomware Virus is considered the new STOP/DJVU variant, just like JYPO, KIFR, KIOP, KITZ, BOZA, BOTY, COZA (find full list here). This means full data decryption is now possible only if you have been affected by offline encryption key. To decrypt your files, you will have to download Emsisoft Decryptor for STOP DJVU, a tool created and maintained by a genius security researcher Michael Gillespie.
Note! Please do not spam the security researcher with questions whether he can recover your files encrypted with online key - it is not possible.
In order to test the tool and see if it can decrypt ZNSM files, follow the given tutorial.
- Download the decryption tool from Emsisoft.
- Click the little arrow next to your download and choose Show in Folder.
- Now, right-click the file and choose Run as Administrator. If asked, enter administrator's password.
- In UAC window, click Yes.
- Click Yes to agree to software terms in both windows.
- The tool will automatically include C:// disk as a location to decrypt. The file recovery tool will prepopulate the locations to scan, including connected data storage drives or network drives. Click Add folder if you wish to add additional locations.
In Options tab, you can choose to keep encrypted file copies. We recommend leaving this option selected, especially if you do not know if the decryption tool will work. - Click Decrypt to start restoring ZNSM files. You will see the progress in the Results tab. Here, you can see messages from the tool, such as whether the decryption procedure is successful, or you need to wait for an update.
You might also be informed that online key was used to encrypt your files. In such case, the decryption tool won't work for you, and the only way to recover your files is to use a data backup.
Meanings of decryptor's messages
The ZNSM decryption tool might display several different messages after failed attempt to restore your files. You might receive one of the following messages:
Error: Unable to decrypt file with ID: [example ID]
This message typically means that there is no corresponding decryption key in the decryptor's database.
No key for New Variant online ID: [example ID]
Notice: this ID appears to be an online ID, decryption is impossible
This message informs that your files were encrypted with online key, meaning no one else has the same encryption/decryption key pair, therefore data recovery without paying the criminals is impossible.
Result: No key for new variant offline ID: [example ID]
This ID appears to be an offline ID. Decryption may be possible in the future.
If you were informed that an offline key was used, but files could not be restored, it means that the offline decryption key isn't available yet. However, receiving this message is extremely good news, meaning that it might be possible to restore your ZNSM extension files in the future. It can take a few months until the decryption key gets found and uploaded to the decryptor. We recommend you to follow updates regarding the decryptable DJVU versions here. We strongly recommend backing up your encrypted data and waiting.
Report Internet crime to legal departments
Victims of ZNSM Ransomware Virus should report the Internet crime incident to the official government fraud and scam website according to their country:
- In the United States, go to the On Guard Online website.
- In Australia, go to the SCAMwatch website.
- In Germany, go to the Bundesamt für Sicherheit in der Informationstechnik website.
- In Ireland, go to the An Garda Síochána website.
- In New Zealand, go to the Consumer Affairs Scams website.
- In the United Kingdom, go to the Action Fraud website.
- In Canada, go to the Canadian Anti-Fraud Centre.
- In India, go to Indian National Cybercrime Reporting Portal.
- In France, go to the Agence nationale de la sécurité des systèmes d’information.
If you can't find an authority corresponding to your location on this list, we recommend using any search engine to look up "[your country name] report cyber crime". This should lead you to the right authority website. We also recommend staying away from third-party crime report services that are often paid. It costs nothing to report Internet crime to official authorities.
Another recommendation is to contact your country's or region’s federal police or communications authority.
Frequently Asked Questions
You can only open ZNSM files if you have the decryption key, or if you were affected by offline encryption type.
To figure out whether you were affected by offline encryption, please go to C:/SystemID/PersonalID.txt and see if the string inside of it ends in t1. You can also try using Emsisoft Decryptor for STOP/DJVU.
Please follow the guidances provided by the official ZNSM decryption tools and believe what they say. If they say it is impossible to decrypt, it really is so. There is no magic tool or human capable of decrypting your files hiding somewhere. Encryption is a technique created to be nearly impossible to decrypt without a special private key (held by the criminals).
We advise scanning with anti-virus, anti-malware, malware removal tools or software like RESTORO to eliminate virus damage on the system. If you do not trust using a single tool, try running one after another. However, we do not recommend keeping several security programs on a computer at once as they can interfere with each other's work.
Beware of fake ZNSM decryption tools circulating around the web. Cyber criminals are uploading them to various shady websites, also might be promoting them via suspicious Youtube videos. These programs can infect your computer even more heavily (Trojans, miners, etc.). We suggest being extremely cautious around the web. If there will be an official STOP/DJVU decryption tool available, it will be widely discussed in public media.
Norbert Webb is the head of Geek’s Advice team. He is the chief editor of the website who controls the quality of content published. The man also loves reading cybersecurity news, testing new software and sharing his insights on them. Norbert says that following his passion for information technology was one of the best decisions he has ever made. “I don’t feel like working while I’m doing something I love.” However, the geek has other interests, such as snowboarding and traveling.
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