How to remove Cat4er Ransomware and decrypt .cat4er files

What is Cat4er Ransomware

Cat4er is a ransomware virus that triggers data encryption upon infecting the targetted system. It does so by assigning the .cat4er extension to make encrypted files look like 1.pdf.cat4er, 1.png.cat4er, 1.xlsx.cat4er, and so forth depending on the original name. After running such changes, the virus creates an HTML file called HOW_FIX_FILES.htm and meant to instruct victims through the decryption process.

As stated in the HTML note, victims can reaccess all the blocked data by going to the attached TOR link and following instructions on how to purchase special decryption software. Victims are given 10 days to decide on paying the ransom worth 0.08 BTC – around 3300$ at the moment of writing this article. After the payment is made, cybercriminals promise to send the declared tools able to decrypt the files. Unfortunately, ransomware actors are the only figures having the necessary keys to unlock your data. These keys are often strongly secured and almost impossible to crack with the help of third-party tools. Thus, the best thing you can do to avoid paying the ransom and getting your files back at the same time is to recover them through backup copies. Simply delete the virus and copy the lost files from external storage back to your PC. If there are no backup copies available on your side but you still want to dodge paying the ransom, give it a try using third-party tools we have presented in the article below. Sometimes ransomware experts manage to expose the keys and unlock data for free due to possible vulnerabilities overlooked by ransomware developers, so it is also worth saving encrypted files in case working solutions appear. Note that it is important to delete the virus prior to trying any recovery manipulations. Learn how to use our tutorial below.

Cat4er Ransomware (ransom note)

Cat4er Ransomware (website)

How Cat4er Ransomware infected your computer

Ransomware infections are usually spread via e-mail spam letters. Such letters are dangerous because they contain malicious attachments disguised as something legitimate. The presence of Word, Excel, PDF, JavaScript, or Executable files named under innocent-looking titles most certainly means they are designed to cause the installation of malware. It is also possible to encounter links in such messages leading to external pages that ask you to download something. This is not the only channel abused by cybercriminals to deliver different kinds of malware – there are many other popular vectors like trojans, fake update/software installers, backdoors, keyloggers, exploits, and others to beware of. To make sure such infections are less likely to happen in the future, pay more attention and be less reliant on dubious content you see on the web. You can familiarize yourself with our guide below to learn more information about protection against threats like Cat4er Ransomware next time you enter online activity.

1. Download Cat4er Ransomware Removal Tool
2. Get decryption tool for .cat4er 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. How to protect from threats like Cat4er Ransomware

Cat4er Ransomware files:


HOW_FIX_FILES.htm
{randomname}.exe


Cat4er Ransomware registry keys:

no information

How to decrypt and restore .cat4er files

Use automated decryptors

Download Kaspersky RakhniDecryptor

Use following tool from Kaspersky called Rakhni Decryptor, that can decrypt .cat4er files. Download it here:

There is no purpose to pay the ransom because there is no guarantee you will receive the key, but you will put your bank credentials at risk.

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 .cat4er files by uploading samples to Dr. Web Ransomware Decryption Service. Analyzing 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 Cat4er Ransomware and removed from your computer you can try to decrypt 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 .cat4er 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.

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.

How to protect computer from viruses, like Cat4er Ransomware, in future

1. Get special anti-ransomware software

Use ZoneAlarm Anti-Ransomware

ZoneAlarm Anti-Ransomware Dashboard

ZoneAlarm Anti-Ransomware Alert

ZoneAlarm Anti-Ransomware Blocked

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.

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. Cat4er 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.

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.