SunnyDay Virus Files of Ransomware — How to remove virus?

The Sunnyday virus belongs under the ransomware type of infection. Ransomware of such sort encrypts all user’s data on the PC (photos, text files, excel sheets, audio files, videos, etc) and appends its specific extension to every file, leaving the !-Recovery_Instructions-!.txt files in every folder which contains the encrypted files.

What is Sunnyday virus?

☝️ A scientifically accurate denomination for the Sunnyday would be “a ransomware malicious agent”.

Sunnyday adds its specific .SunnyDay extension to the title of each encoded file. For instance, an image entitled “photo.jpg” will be changed to “photo.jpg.SunnyDay”. In the same manner, the Excel file named “table.xlsx” will be renamed to “table.xlsx.SunnyDay”, and so forth.

In each directory that contains the encrypted files, a !-Recovery_Instructions-!.txt text file will be found. It is a ransom money memo. It contains information about the ways of paying the ransom and some other information. The ransom note usually contains a description of how to buy the decryption tool from the racketeers. That is it.

Sunnyday summary:
Name Sunnyday Virus
Extension .SunnyDay
Ransomware note !-Recovery_Instructions-!.txt
Detection MSIL/Spy.Agent.DSV, TrojanSpy:Win32/Delgent, Trojan.Ransom.Magniber
Symptoms Your files (photos, videos, documents) have a .SunnyDay extension and you can’t open them.
Fix Tool See If Your System Has Been Affected by Sunnyday virus

In the picture below, you can see what a folder with files encrypted by the Sunnyday looks like. Each filename has the “.SunnyDay” extension added to it.

Sunnyday Virus - encrypted .SunnyDay files

An example of encrypted .SunnyDay files.

How did my machine catch Sunnyday ransomware?

There are plenty of possible ways of ransomware infiltration.

Nowadays, there are three most popular methods for hackers to have ransomware planted in your system. These are email spam, Trojan introduction and peer file transfer.

If you open your mailbox and see letters that look just like notifications from utility services companies, postal agencies like FedEx, Internet providers, and whatnot, but whose addresser is strange to you, beware of opening those emails. They are very likely to have a viral item enclosed in them. Therefore, it is even more dangerous to download any attachments that come with letters like these.

As for the peer networks like BitTorrent or eMule, the threat 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. Our suggestion is that you use trustworthy resources. Also, it is a good idea to scan the directory containing the downloaded items with the anti-malware utility as soon as the downloading is done.

How do I get rid of the Sunnyday virus?

It is important to inform you that besides encrypting your data, the Sunnyday virus will probably install the Azorult Spyware on your computer to get access to credentials to various accounts (including cryptocurrency wallets). That program can extract your credentials from your browser’s auto-filling data.

Often criminals would unblock some of your files so you know that they really have the decryption tool. Since Sunnyday virus is a relatively new ransomware, anti-malware engineers have not yet found a method to reverse its work. However, the anti-ransomware tools are frequently upgraded, so the effective countermeasure may soon arrive.

Of course, if the tamperers do the job of encoding someone’s critical files, the desperate person will probably comply with their demands. However, paying a ransom does not necessarily mean that you’re getting your blocked information back. It is still risky. After obtaining the money, the racketeers may deliver a wrong decryption code to the victim. There were reports of malefactors just vanishing after getting the money without even writing back.

The optimal safety measure against 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. Surely, that might be not enough. The most crucial thing could be that one you were working upon when it all went down. Nevertheless, it is something. It is also reasonable to scan your drives with the anti-malware utility after the OS restoration.

Sunnyday is not the only ransomware of its kind, since there are other specimens of ransomware out there that act in the same manner. Examples of those are Qbaa, Ooii, Fgui, and some others. The two main differences between them and the Sunnyday are the ransom amount and the encoding method. The rest is almost identical: documents become encrypted, their extensions altered, ransom notes are created in each folder containing encrypted files.

Some lucky users were able to decrypt the blocked files with the help of the free software provided by anti-ransomware experts. Sometimes the racketeers accidentally send the decoding code to the wronged in the ransom note. Such an extraordinary fail allows the user to restore the files. But obviously, one should never rely on such a chance. Remember, ransomware is a bandits’ instrument to pull the money out of their victims.

How сan I avert ransomware attack?

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

You can defend your computer from its infiltration within several easy steps:

  • Ignore any letters from unknown mailboxes with unknown addresses, or with content that has nothing to do with something you are expecting (how can you win in a lottery without even taking part in it?). In case the email subject is likely something you are expecting, check all elements of the dubious letter with caution. A hoax letter will surely contain mistakes.
  • Do not use cracked or unknown software. Trojans are often distributed as a part of cracked products, most likely under the guise of “patch” preventing the license check. But dubious programs are very hard to distinguish from trustworthy software, as trojans sometimes have the functionality you seek. You can try searching for information about this software product on the anti-malware forums, but the best way is not to use such software.
Reasons why I would recommend GridinSoft2

Download Removal Tool.

Run the setup file.

Run Setup.exe
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 Scanning

Click on “Clean Now”.

GridinSoft Anti-Malware Scan Result

FAQ

🤔 How can I open “.SunnyDay” files?Is it possible to open“.SunnyDay” files?

Negative. That is why ransomware is so frustrating. Until you decode the “.SunnyDay” files you will not be able to access them.

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

If the “.SunnyDay” files contain some really important information, then you probably have them backed up. If not, there is still a function of System Restore but it needs a Restore Point to be previously saved. The rest of the methods require patience.

🤔 What to do if the Sunnyday ransomware has blocked my PC and I can’t get the activation code.

🤔 And what should I do now?

Many of the blocked files might still be within your reach

  • If you exchanged your important files via email, you could still download them from your online mailbox.
  • You may have shared images or videos with your friends or family members. Simply ask them to post those images back to you.
  • If you have initially downloaded any of your files from the Web, you can try downloading them again.
  • Your messengers, social networks pages, and cloud disks might have all those files as well.
  • Maybe you still have the needed files on your old computer, a portable device, mobile, memory stick, etc.

HINT: You can use file recovery programs4 to get your lost data back since ransomware blocks the copies of your files, deleting the original ones. In the tutorial below, you can see how to recover your files with PhotoRec, but be advised: you won’t be able to do it before you kill the ransomware itself with an anti-malware program.

Also, you can contact the following governmental 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

References

  1. Here’s the list of Top 10 Data Recovery Software Of 2023.

About the author

Brendan Smith

Cybersecurity analyst covering malware families, suspicious files, and detection alerts. Brendan focuses on clear explanations of what a warning means, when it may be a false positive, and which cleanup steps are appropriate.

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