Zwer ransomware: what it is and how to remove it

From our report of Jun 2020 · not reviewed since

Zwer ransomware - malicious program designed for money extortion

Zwer ransomware is a data locking malware that was developed by sophisticated hackers and is a variant of a malware family known as Djvu.

The virus almost exclusively spreads via software cracks and is one of the most popular malware of such type, which targets regular consumers. The main purpose of the infection is to encrypt all music, video, document, picture, and other personal files by appending .zwer extension and preventing access to them.

After the data locking process is complete, Zwer ransomware drops a ransom note called _readme.txt - this file serves as a direct message from the attackers. Inside the note, criminals claim that victims need to pay $490 in Bitcoin in order to recover a unique RSA key to unlock files. For communication purposes, the attackers provide two emails - helpmanager@mail.ch and restoremanager@airmail.cc.

However, paying criminals is not recommended. There is a chance that Emsisoft's decryptor might be able to help you restore .zwer encrypted files, although it is only possible if ransomware used an offline ID to lock the data.

Djvu/STOP malware family that the Zwer file virus belongs to is one of the most extensive ones, and so far, over 230 versions were released. Despite this, .kkll, .nlah, .pezi, .covm, and other variants do not differ much, although the attackers tend to use different contact emails for communication purposes most of the time.

Nonetheless, the ransom note _readme.txt is almost identical, and delivers the following information:

Initially, the attackers are asking for $980 for the Zwer ransomware decryptor, although they promise a 50% discount ($490) if the contact is made within 72 hours of the infection. Besides, they also offer to decipher one file that does not include sensitive information.

These are all tricks that are meant to create a fake sense of trust about attackers' intentions and make users pay for the Zwer virus file recovery tool. Despite this, there is no guarantee that the attackers will send the unique key, as they might simply scam you by taking the money. The decryption tool might also fail to work in the first place.

While many malware of such type eliminate itself after the data locking process is complete, you should still remove Zwer ransomware with a reputable anti-malware software and only then attempt to recover your files. For malware termination, employ powerful security applications, and then scan the computer with PC repair program to avoid the Windows OS reinstallation.

From our report of Jun 2020 · not reviewed since

More from our earlier report on Zwer ransomware

• The best way to eliminate the infection is by scanning the computer with powerful security software, such as or .
• Note: you will not be able to open .zwer files after you delete the infection from your computer, as a unique key is required for that

From our report of Jun 2020 · not reviewed since

You can't open .zwer files: here's what you should do next

Most people who get infected with file locking malware have never previously had to deal with it.

Therefore, it might be a terrifying experience for many, as the invaluable photos, important work, or school documents are no longer available. Users are generally confused about what to do next, as they cannot open .zwer encrypted files.

The correct course of action would be making a full backup of all the encrypted files (if you had backups, you could skip this step) - simply make a copy and place it on the USB stick or another external storage.

Once that is complete, you should then scan the computer with anti-malware software and eliminate the infection. This is were most users believe that anti-malware tools could help them to recover .zwer files, although it could not be further from the truth. Security software is designed to clean the system from malware, and it cannot decrypt data that was locked by ransomware.

Possibly the best chance of recovery besides data backups is the Emsisoft's decryption tool. However, several rules should be met for the recovery process to be successful:

• .zwer files should be encrypted with an offline ID, which means that malware should have failed to contact its remote server. To check if that is the case for you, go to the C: drive on your computer and locate SystemID.txt or PersonalID.txt. Open the file - you should find the list of all the encrypted data IDs. If one of these entries ends with "t1," an offline ID was used for your files, and it might be recovered with the Emsisoft decryption tool.
• If ransomware has failed to remove Shadow Volume Copies, you can recover files by using Windows Previous Versions feature or System Restore.
• Third-party recovery applications might be able to restore working versions of your files (however, this is not decryption!), as long as you did not use your computer a lot after the infection.

From our report of Jun 2020 · not reviewed since

Zwer ransomware could install the data-stealing module on your machine

Once the malicious file such as b71d.tmp.exe is executed on a Windows machine, it will execute a series of system changes in order to perform a successful file encryption process.

For that, the malware creates subfolders inside %AppData%, %User% or %Temp% folder, and then populates malicious files all over the operating system.

After that, Zwer ransomware performs the following changes:

As soon as the compromised machine is ready, Zwer ransomware initiates file encryption process which targets the most commonly used types, such as PDF, MS Office, text, archive, and other files. During this development, malware is programmed to deliver users fake Windows update pop-up, as it misleads victims to believe that it is real.

However, as soon as the encryption is finished, users then notice that none of the personal files can be opened anymore, and the ransom note is present on the system, explaining that they have to pay for data recovery.

• Deletes Shadow Volume Copies to prevent a quick file recovery
• Opens and modifies Windows registry keys in order to launch with each system boot;
• Creases new and terminates some vital processes;
• Modifies Windows hosts file to prevent users from accessing security-related websites and seeking help with decryption;
• Injects a data-stealing module into the web browsers (this feature is especially dangerous, as sensitive information such as credit card details could be stolen by the attackers if Zwer ransomware removal is not performed on time).

From our report of Jun 2020 · not reviewed since

Watch out - Fake Djvu decryptor can encrypt .zwer files

Cybersecurity experts warn Djvu victims not to rely on offers to download free decryption tools for the latest variants of this ransomware family.

At the beginning of June 2020, a strain of the Jigsaw ransomware has been found impersonating the long-awaited DJVU decrypter.

Spread via underground forums, phishing websites, and hacked ads, the alleged Djvu decrypter contains a malicious crab.exe executable, which stands for a ransomware payload. Unfortunately, victims who have their files already locked tend to act recklessly. Upon the phases of panic, the victims are looking for ways to unlock files, thus suchlike offers are extremely tempting.

However, once the user indicates the ID number, file extension, and clicks the "Scan now" button, the crab.exe file is launched allowing the ransomware to disable enable malicious processes, disable core Windows processes, turn security tools idle, etc.

The Zorab ransomware is a malicious piece of software, which re-encrypts files encrypted by any Djvu variant and appends .ZBR file extension to each of them. Besides, it removed the _readme-txt file developed by the first file-encrypting virus and leaves its own note --DECRYPT--ZORAB.txt.ZRB. The informational note demands people to write an email to zorab28@protonmail.com for further directions.

Unfortunately, just like the latest Djvu variants cannot be decrypted, .ZRB files cannot be recovered without the payment for criminals. However, researchers are under investigation of this threat, so do not rush to pay the ransom.

If you have been attacked by Zwer ransomware, which has been subsequently double-encrypted by Zorab ransomware, reboot your machine into Safe Mode with Networking and launch AV scanner.

NOTE: The fake DJVU decrypter tricks victims into believing that it's can recover the versions of Djvu based on online keys and launched after August 2019. That is not true. Zwer ransomware and its predecessors can't be decrypted for free.

From our report of Jun 2020 · not reviewed since

Here's how ransomware managed to lock your files, and how to prevent it from happening in the future

As mentioned above, Djvu variants are mainly spread via software cracks.

These files are used to bypass the licensing process of various applications and are essentially illegal. However, since cracks, keygens, loaders, and similar tools are widely popular, many do not even suspect that some of these could be malicious. Therefore it is highly advisable staying away from files that are download via torrent or similar insecure sites.

Another reason to stop downloading software cracks is that there is simply no way to check whether the file is actually malicious. Cracks, keygens, and similar tools are designed in a way that would break the code of another application. Therefore, even the most advanced security programs are going to flag the item as malicious, regardless if it is infected with malware or not.

Security experts from dieviren.de also advise following these precautionary measures in order to avoid ransomware infections via the third-party websites that host illegal software downloads:

Finally, to negate most of the harmful ransomware infection effects, backup your files on a portable storage device or a remote cloud service.

• Employ powerful anti-malware software with real-time detection feature and keep it updated at all times;
• Install ad-blocking browser extension to prevent the execution of background code within malicious ads;
• Pay attention to the file names that you download. For example, malicious actors often obfuscate file names by using double extensions, such as "file.mp4.exe";
• Before downloading anything, check out user comments;
• Beware of copycat websites that mimic such sites like The Pirate Bay - these are riddled with malware;
• Set Java and Adobe Flash to run on click;
• Make sure all the latest updates are installed on your computer.

From our report of Jun 2020 · not reviewed since

Zwer ransomware removal explained

It is important to understand what type of changes the malware makes to the infected machine in order to remove Zwer ransomware in the correct way.

First of all, you should go to the following location and delete the "hosts" file located there:

After that, you should make a full backup of the encrypted files - use something convenient like a USB stick, or upload all the data to a remote server (Google Drive, OneDrive, Dropbox). This will ensure that it will not get corrupted as soon as you perform Zwer ransomware removal. Note that encrypted files are not malicious, as they do not hold any malicious code inside of it.

Next, you should download and install a reputable anti-malware tool and perform a full system scan. In case there issues with the process, access Safe Mode with Networking, as we explain below. Finally, you can attempt the file .zwer file recovery process - we list all the solutions you can try below.

[GI=method-1]In case the need arises during Zwer virus removal process, access Safe Mode with Networking:

[GI=method-2]You can use System Restore to eliminate malware from your system:

Windows Previous Versions Feature might be useful when trying file recovery

If you have enabled System Restore prior to the infection, you can attempt to retrieve data with the help of the Windows Previous Versions feature.

ShadowExplorer might save all your files

In case the virus failed to eliminate Shadow Volume Copies, use ShadowExplorer to recover your data.

Try out Emsisoft's decryption tool

Emsisoft decryptor is a tool that can help some of the Djvu ransomware victims. Keep in mind that it can only word for files that were locked with an offline ID. Note that this functionality is not available for all malware variants.