How to remove Qual Ransomware and decrypt .qual files

What is Qual Ransomware

Qual Ransomware is a malicious program identified as part of the Djvu ransomware family, designed to encrypt files on an infected system and demand a ransom for their decryption. When Qual executes, it appends the .qual extension to the name of each encrypted file, rendering them inaccessible without the decryption key. For example, a file initially named photo.jpg will be renamed to photo.jpg.qual. The encryption mechanism employed by Qual is robust, typically utilizing advanced cryptographic algorithms that make decryption without the corresponding decryption key virtually impossible. After encrypting the files, Qual drops a ransom note in a text file named _readme.txt, which can usually be found in every folder containing encrypted files. This note instructs the victim to contact the attackers via specific email addresses and outlines the ransom amount required for the decryption tool, often offering a discount if payment is made within a certain timeframe.

Currently, decryption of files affected by newer versions of Qual is highly problematic due to the sophisticated encryption methods used. While there are no universal decryption tools available for these newer versions, victims whose data has been encrypted using offline keys might have a chance to recover their files using the Emsisoft STOP Djvu Decryptor. This tool, developed by Emsisoft in collaboration with cybersecurity researcher Michael Gillespie, can potentially decrypt files if the encryption was not executed with an online key. To decrypt .qual files, users would need to identify whether their specific case involves an offline key, then use the Emsisoft STOP Djvu Decryptor by uploading a pair of the same file before and after encryption. This process may take some time and requires a stable internet connection for the decryption process to be successful. It is important to note that while this method offers some hope, it is not a guaranteed solution, as many instances of Qual ransomware involve online keys that the decryption tool cannot address.

How Qual Ransomware infects computers

Qual Ransomware, a member of the notorious Djvu ransomware family, primarily infiltrates computers through phishing and social engineering techniques. Users are often tricked into downloading malicious attachments or clicking on deceptive links embedded in spam emails, instant messages, or social media posts. Additionally, the ransomware can be bundled with seemingly legitimate software from dubious download sources, including freeware sites and Peer-to-Peer (P2P) networks. Drive-by downloads from compromised or malicious websites also serve as a common infection vector. Once inside, Qual Ransomware employs multi-stage infection chains, utilizing shellcodes and techniques like dynamic API resolution and process hollowing to evade detection and encrypt the victim’s files, appending them with a “.qual” extension.

1. Download Qual Ransomware Removal Tool
2. Get decryption tool for .qual files
3. Recover encrypted files with Stellar Data Recovery Professional
4. Restore encrypted files with Windows Previous Versions
5. Restore files with Shadow Explorer
6. Restore media files with Media Repair
7. How to protect from threats like Qual Ransomware

Virus modifies “hosts” file to block Windows updates, downloading antivirus programs, and visiting sites related to security news or offering security solutions. Qual Ransomware comes along with AZORult trojan, which was initially created to steal logins and passwords. The process of infection also looks like installing Windows updates, the malware shows a fake window, that mimics the update process.

It uses rdpclip.exe to replace a legal Windows file and to launch an attack on a computer network. After encrypting the files, the encrypter is deleted using the delself.bat command file. Qual Ransomware virus is propagated via spam attack with malicious e-mail attachments and using manual PC hacking. Can be distributed by hacking through an unprotected RDP configuration, fraudulent downloads, exploits, web injections, fake updates, repackaged, and infected installers. The virus assigns a certain ID to the victims, which is used to name those files and supposedly to send a decryption key. Great tools to protect against Qual Ransomware are: Emsisoft Anti-Malware and Malwarebytes Anti-Malware.

How to remove Qual Ransomware manually

Kill Qual Ransomware Process

1. Press Ctrl + Shift + Esc keys simultaneously to open the Windows Task Manager.
2. Select the Processes tab and look for any suspicious processes related to Qual Ransomware.
3. Right-click on the malicious process and select Open file location. This step is necessary to remove executable file after this.
4. Right-click on the malicious process and select End Task or End Process option.

Disable Qual Ransomware Start-up Entry

1. Press Win + R keys together to open the Run dialog box.
2. Type msconfig and press Enter to open the System Configuration window.
3. Go to the Startup tab and look for any suspicious entries related to Qual Ransomware.
4. Uncheck the box next to the malicious entry and click OK to disable it.

Delete Qual Ransomware Task

1. Press Win + R keys together to open the Run dialog box.
2. Type taskschd.msc and press Enter to open the Task Scheduler.
3. Look for any tasks related to Qual Ransomware in the Task Scheduler Library.
4. Right-click on the malicious task and select Delete or Disable option.

Remove Qual Ransomware Executable Files

1. Open folder that was opened on the third step of the first instruction Kill Qual Ransomware Process.
2. Find Qual Ransomware executable file.
3. Right-click on the malicious executable file and select Delete to remove it.
4. To be able to do this you will need to modify permissions fo this file in the instruction below.

Disable inheritance for executable files

1. Right-click on the affected folder and click Properties.
2. Click the Security tab and then click the Advanced button.
3. In the Advanced Security Settings window, click the Disable inheritance button.
4. Choose Convert inherited permissions into explicit permissions on this object to remove inherited permissions.
5. Now you will be able to delete the file.

It is not recommended to remove Qual Ransomware manually, for safer solution use Removal Tools instead.

Qual Ransomware files:

_readme.txt
rdpclip.exe
delself.bat
{randomname}.exe

Qual Ransomware registry keys:

no information

How to decrypt and restore .qual files

Use automated decryptors

Download STOP Djvu Decryptor from EmsiSoft (.qual variations)

IMPORTANT: Read this detailed guide on using STOP Djvu Decryptor to avoid file corruption and time wasting.

STOP Djvu Decryptor is able to decrypt .qual files, encrypted by Qual Ransomware. This tool was developed by EmsiSoft. It works in automatic mode, but in most cases works only for files encrypted with offline keys. Download it here:

Download STOP Djvu Decryptor

Dr.Web Rescue Pack

Famous antivirus vendor Dr. Web provides free decryption service for the owners of its products: Dr.Web Security Space or Dr.Web Enterprise Security Suite. Other users can ask for help in the decryption of .qual files by uploading samples to Dr. Web Ransomware Decryption Service. Analysis of files will be performed free of charge and if files are decryptable, all you need to do is purchase a 2-year license of Dr.Web Security Space worth $120 or less. Otherwise, you don’t have to pay.

If you are infected with Qual Ransomware and removed it from your computer, you can try decrypting your files. Antivirus vendors and individuals create free decryptors for some crypto-lockers. To attempt to decrypt them manually you can do the following:

Use Stellar Data Recovery Professional to restore .qual files

1. Download Stellar Data Recovery Professional.
2. Click Recover Data button.
3. Select type of files you want to restore and click Next button.
4. Choose location where you would like to restore files from and click Scan button.
5. Preview found files, choose ones you will restore and click Recover.

Download Stellar Data Recovery Professional

Using Windows Previous Versions option:

1. Right-click on infected file and choose Properties.
2. Select Previous Versions tab.
3. Choose particular version of the file and click Copy.
4. To restore the selected file and replace the existing one, click on the Restore button.
5. In case there is no items in the list choose alternative method.

Using Shadow Explorer:

1. Download Shadow Explorer program.
2. Run it and you will see screen listing of all the drives and the dates that shadow copy was created.
3. Select the drive and date that you want to restore from.
4. Right-click on a folder name and select Export.
5. In case there are no other dates in the list, choose alternative method.

If you are using Dropbox:

1. Login to the DropBox website and go to the folder that contains encrypted files.
2. Right-click on the encrypted file and select Previous Versions.
3. Select the version of the file you wish to restore and click on the Restore button.

Use Media Repair to decrypt media files encrypted with .qual

1. Download Media Repair tool.
2. Right-click on the downloaded archive, and select Extract to Media_Repair\.
3. Then double-click on the extracted .exe file to launch the utility.
4. At first, you have to choose which file type you want to decrypt. You can do it from the drop-down menu in the utility.
5. Next, browser the folder with encrypted or reference files. Choose any of them and click on the Test icon located in the top right corner.
6. Media Repair will display a pop-up message with information on whether it can repair the selected file or not.
7. After checking if it is possible or not, select your reference file and click on the icon right under the Test button we used in step #5.
8. If the file pair is properly matched, you can move on and hit the Play button to start repairing. You can also stop the process anytime by clicking on the Stop button.

How to protect computer from viruses, like Qual Ransomware, in future

1. Get special anti-ransomware software

Use G-DATA STOP/Djvu vaccine

G DATA has released a vaccine to block STOP/DJVU ransomware from encrypting victims’ files after infection. The vaccine prevents the ransomware from encrypting files anymore, but it does not prevent the infection itself. The vaccine is available on GitHub. Download it below:

Download STOP/Djvu vaccine

Use ZoneAlarm Anti-Ransomware

Famous antivirus brand ZoneAlarm by Check Point released a comprehensive tool, that will help you with active anti-ransomware protection, as an additional shield to your current protection. The tool provides Zero-Day protection against ransomware and allows you to recover files. ZoneAlarm Anti-Ransomware is compatible with all other antiviruses, firewalls, and security software except ZoneAlarm Extreme (already shipped with ZoneAlarm Anti-Ransomware) or Check Point Endpoint products. The killer features of this application are: automatic file recovery, overwrite protection that instantly and automatically recovers any encrypted files, file protection that detects and blocks even unknown encryptors.

Download ZoneAlarm Anti-Ransomware

2. Back up your files

As an additional way to save your files, we recommend online backup. Local storage, such as hard drives, SSDs, flash drives, or remote network storage can be instantly infected by the virus once plugged in or connected to. Qual Ransomware uses some techniques to exploit this. One of the best services and programs for easy automatic online backup is iDrive. It has the most profitable terms and a simple interface. You can read more about iDrive cloud backup and storage here.

Download iDrive

3. Do not open spam e-mails and protect your mailbox

Malicious attachments to spam or phishing e-mails are the most popular method of ransomware distribution. Using spam filters and creating anti-spam rules is good practice. One of the world leaders in anti-spam protection is MailWasher Pro. It works with various desktop applications and provides a very high level of anti-spam protection.

Download MailWasher Pro