How to remove Efji ransomware

Efji ransomware – a file renaming virus that will lock down all your data asking for money to recover your docs

Efji ransomware is a computer virus that is designed to encrypt all pictures, music, documents, databases, and other files on users' machines by appending .efji extension to them. Suchlike files can no longer be modified or opened and lose original icons. The malware belongs to a well-known family of Djvu – it is known to be spread via fake installers, cracks, and malicious websites hosting pirated software. This variant was first spotted in the second half of October 2020 and is an addition to other 257 versions released so far.

Once installed, the Efji virus drops a ransom note _readme.txt, which explains to victims what happened to their files. Crooks claim that only they have access to a decryption key that is required to unlock all the files and ask for $980/$490 for it, to be paid in bitcoin. To establish communication, hackers provide two email addresses – helpmanager@mail.ch or restoremanager@airmail.cc, although security experts recommend avoiding all contact. Since the Efji ransomware virus is a part of Djvu, users whose files were encrypted with an offline ID could recover their files with a free decryptor available from Emsisoft.

Efji ransomware targets almost all versions of 64 and 32-bit Windows machines – its primary executable can be named as anything, although, since malware is distributed via software cracks, it is likely to be named as such. This particular variant can be detected by most security applications, so users should never ignore these warnings (in other words, Efji removal will be performed before malware managers to encrypt any files). On Virus Total, the virus is detected as follows:^[1]

• HEUR:Trojan.Win32.Bsymem.gen
• Ransom:Win32/STOP.BS!MTB
• Trojan.GenericKDZ.70771
• Win32:MalwareX-gen [Trj]
• Generic.mg.033215ae5330dc16, etc.

As soon as the Efji virus manages to access the computer, it modifies the Windows registry, deletes Shadow Copies, drops many malicious files, modifies Windows “hosts” file, establishes background connections, and performs other system changes, which are meant to prepare the system from the encryption process to be successful. These modifications might be difficult to reverse with regular anti-malware tools, so we recommend using FortectIntego for this process.

Computer modifications are then following with data encryption – Efji ransomware targets the most commonly-used personal file types, including PDF, RAR, JPG, DOC, and many others. It is evident that the attackers intend to cause maximum damage to victims to increase the possibility of a ransom payment.

Once the encryption is complete, the Efji virus delivers the following ransom note:

ATTENTION!

Don't worry, you can return all your files!
All your files like pictures, 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:
https://we.tl/t-7WqJh5indg
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:
helpmanager@mail.ch

Reserve e-mail address to contact us:
restoremanager@airmail.cc

Your personal ID:

Crooks offer you a decryption tool for $980, although they also say that they are willing to drop that price by 50% if you contact them fast enough. They also provide a seemingly “free” test decryption that is meant to serve as proof that the .efji file extension can be removed with the help of the tool they have. Despite all this, security experts^[2] advise avoiding all contact with criminals, as they might never provide the required decryptor, despite the payment.

Many ransomware self-delete after the encryption is performed, although you should still remove Efji ransomware with powerful anti-malware tools, such as SpyHunterCombo Cleaner or MalwarebytesMalwarebytes. This is because there is still a possibility that malware will continue to encrypt the incoming files, and it is also known to drop a data-stealing module on the PC (you might disclose your sensitive information, such as logins and banking information, to the attackers). Besides, variants of Djvu were previously spread with other malware, so additional infections could be present as well.

How to deal with .efji extension files without backups

As evident, the best way to recover .efji files is by using backups. Unfortunately, most users infected with ransomware never had to deal with it before and never kept the backups for unforeseen circumstances like that. Please keep in mind that ransomware is not the only way you can lose your important files, so it is vital to prepare reliable backups regularly.

So, how can you recover .efji virus files without backups? The answer is not that simple, as the recovery options and the probability depend on many factors. Just to make it clear, anti-malware software will not help you recover your files, despite the popular belief. In other words, you can delete malware-related files, but your personal data will remain encrypted. Security software is simply not designed to restore files encrypted by ransomware.

Ransomware authors use a sophisticated RSA encryption algorithm^[3] to lock data, which means that even the most powerful computers would not be able to compute the required key. And unfortunately, only the attackers have access to the unique key needed to unlock .efji files.

Several other methods might be able to help some victims, which include:

• Using Emsisoft decryptor. This tool will only work if your files were locked with an offline ID, i.e., static key. However, somebody with the same ransomware version needs to pay the ransom, retrieve the key, and then share it with Emsisoft researchers. Thus, even if your data is encrypted with an offline ID, it might take some time before you can recover it using the decryptor.
• Third-party recovery programs might sometimes be useful, although they are unlikely to restore all your files.
• In case malware failed to delete built-in Windows backups, you can employ Windows Previous Versions and other methods listed below.

How to use Djvu decryptor from Emsisoft?

Keep in mind that Efji file virus might not be decryptable even for those who have their data encrypted with an offline ID for quite some time. One of the users who got encrypted with this variant needs to retrieve the offline key from the attackers and then share it with Emsisoft security researchers. Thus, if the tool does not work for you yet, you should wait some time and try it later.

Here's how to use it:

1. Download Emsisoft's decryptor for Djvu [download link].
2. Click on the decrypt_STOPDjvu.exe file at the bottom-left of your browser tab.
3. Agree to License Terms.
   
   
4. Click OK when Disclaimer window shows up.
   
5. The Decryptor should automatically populate the encrypted file folders, although you can add them manually as well by pressing Add folder.
   
   
6. The tool will run for sometime and report whether your files can be decrypted.

From here, there are three outcomes that are available:

1. “Decrypted!” will be shown under files that were decrytped successfully – they are now usable again.
   
2. “Error: Unable to decrypt file with ID:” – this means that the offline keys for this version of Djvu has not been recovered yet (should try later).
   
3. “This ID appears to be an online ID, decryption is impossible” – as description explains, decryption is not possible with the decryptor.

What else can you do to restore your files?

Efji encrypts all files on the system, including video, music, and others. Since Djvu only encrypts the first 150KB of each of the files, some media players will be capable of playing some of such files, just without the first few seconds that were locked. Besides, you can re-download files such as MP3s from the internet.

You should also not forget about other data recovery methods that should be available for you personally. For example, if you sent an important Excel sheet to your coworker, you can retrieve it from your email. You should also check strage devices such as your phone, USB sticks, and similar – you might find at least some of the important files. Likewise, if you have set the OneDrive or Google Drive backup, you can retrieve your data easily.

Employ correct tools for Efji ransomware removal

First of all, if you were infected with the virus, you will not be able to access most security-focused websites that attempt to help users with Efji ransomware removal, all because of the “hosts” file modification by malware. Therefore, you should go to the following location and delete this file, as it will be re-created automatically without any restrictions (alternatively, if you used the “hosts” file before and added some entries, delete the ones that were added by the malware):

C:\Windows\System32\drivers\etc\

Next, you should copy all the personal files before you remove Efji ransomware from the system. Malware termination might sometimes permanently corrupt files, so it is better to back them up. Note that encrypted data does not hold any malicious code, so it is safe to copy.

You can then delete Efji virus from the computer by using powerful anti-malware solutions, such as SpyHunterCombo Cleaner or MalwarebytesMalwarebytes (while manual elimination is possible, it is way too difficult for regular computer users). If required, you can also access Safe Mode with Networking as explained below, although this step is not always needed. If you spot that your Windows machine is crashing, lagging, delivering errors and suffering from similar stability issues, it means that some of the system files were damaged. To fix this damage, we recommend using an automated repair tool FortectIntego.

Finally, you can then attempt to retrieve your .Efji files with the help of the instructions we provide in our recovery section below, although keep in mind that chances of success are relatively low (but never zero!). We have also prepared a video guide for you to see the steps of Efji virus removal visually. The video will help you for better understanding of the virus itself and hopefully, you might try recovering the files without paying the ransom.

We also highly recommend you contact your local law enforcement agency if you suffered a ransomware attack – it could help with finding the culprits one day. Here are a few links for particular countries:

• U.S – On Guard Online;
• UK – Action Fraud;
• Germany – Bundesamt für Sicherheit in der Informationstechnik;
• France – Agence nationale de la sécurité des systèmes d’information;
• Australia – SCAMwatch;
• New Zealand – Consumer Affairs Scams;
• Canada – Canadian Anti-Fraud Centre.

If your country is not listed above, visit a police office or a website of the agency dealing with online scams and fraud.

Video guide for Efji ransomware removal and data recovery solutions