CAT4ER Virus (.CAT4ER Files of Ransomware) — How to remove virus?

Written by Brendan Smith
The Cat4er virus belongs to the ransomware type of infection. Malware of such sort encrypts all user’s data on the computer (images, text files, excel tables, music, videos, etc) and appends its specific extension to every file, creating the HOW_FIX_FILES.htm text files in every folder with the encrypted files.
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What is known about the Cat4ervirus?

☝️ A strictly correct designation for the Cat4er would be “a ransomware-type malicious agent”.

Cat4er adds its specific .Cat4er extension to the title of every encrypted file. For example, a file entitled “photo.jpg” will be changed to “photo.jpg.Cat4er”. Likewise, the Excel file named “table.xlsx” will be altered to “table.xlsx.Cat4er”, and so on.

In every folder containing the encrypted files, a HOW_FIX_FILES.htm text document will appear. It is a ransom money memo. It contains information on the ways of paying the ransom and some other information. The ransom note most probably contains instructions on how to purchase the decryption tool from the tamperers. That is it.

Cat4er summary:
NameCat4er Virus
Extension.Cat4er
Ransomware noteHOW_FIX_FILES.htm
Detection1Win32/ClipBanker.IR, MSIL/Filecoder.WannaScream.A, Trojan:Win32/Danabot.RPY!MTB
SymptomsYour files (photos, videos, documents) get a .Cat4er extension and you can’t open them.
Fix ToolSee If Your System Has Been Affected by Cat4er virus

In the screenshot below, you can see what a folder with files encrypted by the Cat4er looks like. Each filename has the “.Cat4er” extension appended to it.

Cat4er Virus - encrypted .Cat4er files

That is how encrypted “.Cat4er” files look.

How did my computer get infected with Cat4er ransomware?

There is a huge number of possible ways of ransomware infiltration.

There are currently three most popular methods for hackers to have ransomware settled in your system. These are email spam, Trojan infiltration and peer networks.

If you access your inbox and see emails that look just like notifications from utility services companies, delivery agencies like FedEx, web-access providers, and whatnot, but whose addresser is strange to you, beware of opening those emails. They are most likely to have a ransomware file enclosed in them. So it is even riskier to open any attachments that come with emails like these.

Another thing the hackers might try is a Trojan horse model2. A Trojan is a program that infiltrates into your machine disguised as something different. For example, you download an installer of some program you want or an update for some software. But what is unboxed reveals itself a harmful agent that compromises your data. Since the update file can have any name and any icon, you’d better be sure that you can trust the resource of the things you’re downloading. The optimal thing is to trust the software companies’ official websites.

As for the peer-to-peer file transfer protocols like torrent trackers or eMule, the danger is that they are even more trust-based than the rest of the Web. You can never guess what you download until you get it. So you’d better be using trustworthy resources. Also, it is a good idea to scan the directory containing the downloaded items with the antivirus as soon as the downloading is complete.

How to remove the Cat4er virus?

It is crucial to inform you that besides encrypting your data, the Cat4er virus will most likely install the Azorult Spyware on your computer to get access to credentials to different accounts (including cryptocurrency wallets). The mentioned program can extract your credentials from your browser’s auto-filling data.

Often tamperers would decrypt several of your files so you know that they do have the decryption tool. Since Cat4er virus is a relatively recent ransomware, anti-malware engineers have not yet found a method to reverse its work. However, the anti-ransomware instruments are constantly updated, so the effective countermeasure may soon arrive.

Understandably, if the hackers succeed in encoding someone’s essential data, the desperate person will probably comply with their demands. However, paying to racketeers does not necessarily mean that you’re getting your data back. It is still dangerous. After getting the money, the racketeers may send a wrong decryption key to the injured party. There were reports of malefactors simply vanishing after getting the money without even bothering to reply.

The optimal countermeasure to ransomware is to have aan OS restore point or the copies of your essential files in the cloud storage or at least on an external drive. Obviously, that might be not enough. Your most important thing could be that one you were working on when it all went down. But at least it is something. It is also wise to scan your drives with the antivirus program after the system is rolled back.

There are other ransomware products, besides Cat4er, that work similarly. Examples of those are Xcmb, Hudf, Yjqs, and some others. The two main differences between them and the Cat4er are the ransom amount and the encoding method. The rest is the same: files become encrypted, their extensions altered, ransom notes appear in each directory containing encoded files.

Some lucky victims were able to decode the arrested files with the help of the free tools provided by anti-malware specialists. Sometimes the racketeers mistakenly send the decoding code to the victims in the ransom note. Such an epic fail allows the victim to restore the files. But obviously, one should never rely on such a chance. Make no mistake, ransomware is a tamperers’ tool to pull the money out of their victims.

How do I avert ransomware infiltration?

Cat4er ransomware doesn’t have a endless power, neither does any similar malware.

You can defend your computer from its injection taking three easy steps:

  • Ignore any letters from unknown senders with strange addresses, or with content that has nothing to do with something you are waiting for (how can you win in a money prize draw without even taking part in it?). In case the email subject is more or less something you are expecting, check all elements of the suspicious email with caution. A fake letter will surely contain mistakes.
  • Avoid using cracked or unknown programs. Trojans are often shared as an element of cracked products, most likely under the guise of “patch” to prevent the license check. Understandably, untrusted programs are very hard to tell from reliable software, as trojans sometimes have the functionality you need. You can try searching for information on this program on the anti-malware forums, but the optimal way is not to use such software.
  • And finally, to be sure about the safety of the objects you downloaded, check them with GridinSoft Anti-Malware. This program will be a perfect shield for your PC.
Reasons why I would recommend GridinSoft3

There is no better way to recognize, remove and prevent ransomware than to use an anti-malware software from GridinSoft4.

Download Removal Tool.

You can download GridinSoft Anti-Malware by clicking the button below:

Run the setup file.

When setup file has finished downloading, double-click on the setup-antimalware-fix.exe file to install GridinSoft Anti-Malware on your system.

Run Setup.exe

An User Account Control asking you about to allow GridinSoft Anti-Malware to make changes to your device. So, you should click “Yes” to continue with the installation.

GridinSoft Anti-Malware Setup

Press “Install” button.

GridinSoft Anti-Malware Install

Once installed, Anti-Malware will automatically run.

GridinSoft Anti-Malware Splash-Screen

Wait for the Anti-Malware scan to complete.

GridinSoft Anti-Malware will automatically start scanning your PC for Cat4er infections and other malicious programs. This process can take a 20-30 minutes, so I suggest you periodically check on the status of the scan process.

GridinSoft Anti-Malware Scanning

Click on “Clean Now”.

When the scan has finished, you will see the list of infections that GridinSoft Anti-Malware has detected. To remove them click on the “Clean Now” button in right corner.

GridinSoft Anti-Malware Scan Result

Frequently Asked Questions

🤔 How can I open “.Cat4er” files?Can I somehow access “.Cat4er” files?

Unfortunately, no. You need to decipher the “.Cat4er” files first. Then you will be able to open them.

🤔 The encrypted files are very important to me. How can I decrypt them quickly?

If the “.Cat4er” files contain some really important information, then you probably have them backed up. Otherwise, you might try to employ System Restore. The only question is whether you have saved any Restore Points that would be helpful now. There are other ways to beat ransomware, but they take time.

🤔 Will GridinSoft Anti-Malware remove all the encrypted files alongside the Cat4er virus?

Absolutely not! The encrypted files are not harmful, so they won’t be deleted.

GridinSoft Anti-Malware will delete actual viruses from your PC. The ransomware that has infiltrated your system is must be still functional and running scans every so often to encrypt any new files you might create on your PC after the infection. As it has been said above, the Cat4er ransomware comes with the company. It installs backdoors and keyloggers that can steal your account credentials and provide criminals with easy access to your system in the future.

🤔 What actions should I take if the Cat4er ransomware has blocked my PC and I can’t get the activation key.

In such a case, you need to prepare a memory stick with a pre-installed Trojan Killer. Use Safe Mode to perform the procedure. The point is that the ransomware runs automatically as the system boots and encrypts any new files created or brought into your machine. To stop this function – use Safe Mode, which allows only the essential programs to run upon system boot. Consider reading our manual on running Windows in Safe Mode.

🤔 What can I do right now?

Many of the encoded files might still be within your reach

  • If you sent or received your important files by email, you could still download them from your online mail server.
  • You may have shared images or videos with your friends or family members. Simply ask them to send those pictures back to you.
  • If you have initially downloaded any of your files from the Internet, you can try doing it again.
  • Your messengers, social networks pages, and cloud drives might have all those files too.
  • It might be that you still have the needed files on your old computer, a portable device, phone, memory stick, etc.

USEFUL TIP: You can use data recovery utilities5 to get your lost data back since ransomware encrypts the copies of your files, deleting the authentic ones. In the video below, you can see how to recover your files with PhotoRec, but remember: you won’t be able to do it before you kill the ransomware itself with an antivirus program.

Also, you can contact the following official fraud and scam sites to report this attack:

To report the attack, you can contact local executive boards. For instance, if you live in USA, you can have a talk with FBI Local field office, IC3 or Secret Service.

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Brendan Smith
How to Remove CAT4ER Ransomware & Recover PC

Name: CAT4ER Virus

Description: CAT4ER Virus is a ransomware-type infections. This virus encrypts important personal files (video, photos, documents). The encrypted files can be tracked by a specific .Cat4er extension. So, you can't use them at all.

Operating System: Windows

Application Category: Virus

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References

  1. Encyclopedia of threats.
  2. You can read more on Trojans, their use and types in the Trojan-dedicated section of GridinSoft official website.
  3. GridinSoft Anti-Malware Review from HowToFix site: https://howtofix.guide/gridinsoft-anti-malware/
  4. More information about GridinSoft products: https://gridinsoft.com/products/
  5. Here are the top 10 file recovery tools of 2021.

About the author

Brendan Smith

Journalist, researcher, web content developer, grant proposal editor. Efficient and proficient on multiple platforms and in diverse media. Computer technology and security are my specialties.

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