SIGRUN Virus 🔐 (.SIGRUN Files) — How to Remove?

The Sigrun virus falls under the ransomware type of malicious agent. A harmful program of such sort encrypts all the data on your computer (photos, documents, excel sheets, audio files, videos, etc) and adds its own extension to every file, creating the RESTORE-SIGRUN.txt text files in every directory containing encrypted files.

Sigrun virus: what is known so far?

☝ A scientifically accurate denomination for the Sigrun is “a ransomware-type infection”.

Sigrun adds its extra .sigrun extension to every file’s name. For example, a file entitled “photo.jpg” will be turned into “photo.jpg.sigrun”. In the same manner, the Excel file named “table.xlsx” will become “table.xlsx.sigrun”, and so forth.

In each directory containing the encoded files, a RESTORE-SIGRUN.txt text document will be found. It is a ransom money memo. It contains information on the ways of contacting the racketeers and some other remarks. The ransom note usually contains a description of how to buy the decryption tool from the Sigrun developers. You can obtain this decryptor after contacting [email protected] through email. That is basically the scheme of the felony.

Sigrun outline:
Name Sigrun Virus
Extension .sigrun
Ransomware note RESTORE-SIGRUN.txt
Ransom $500-$1500
Contact [email protected]
Detection Trojan.Ransom.VirLock, Ransom:MSIL/Cryptolocker.EK!MTB, Ransom:Win32/MedusaLocker.B!MTB
Symptoms Your files (photos, videos, documents) have a .sigrun extension and you can’t open them.
Fix Tool See If Your System Has Been Affected by Sigrun virus

The RESTORE-SIGRUN.txt document accompanying the Sigrun malware states the following:

~~~~~~SIGRUN RANSOMWARE~~~~~~~~~

Dear user, all your important files have been encrypted!
Don\'t worry! Your files still can be restored by us!

In order to restore it you need to contact with us via e-mail.
[email protected]
As a proof we will decrypt 3 files for free!

Please, attach this to your message: -

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

Sigrun Virus - encrypted .sigrun files

An example of encrypted .sigrun files.

How did Sigrun ransomware end up on my PC?

There are plenty of possible ways of ransomware infiltration.

Nowadays, there are three most exploited ways for malefactors to have ransomware settled in your digital environment. These are email spam, Trojan introduction and peer-to-peer networks.

If you open your mailbox and see emails that look like familiar notifications from utility services companies, delivery agencies like FedEx, Internet providers, and whatnot, but whose “from” field is strange to you, beware of opening those emails. They are most likely to have a viral item attached to them. So it is even more dangerous to download any attachments that come with letters like these.

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

How to remove the Sigrun virus?

It is important to inform you that besides encrypting your data, the Sigrun virus will most likely deploy the Azorult Spyware on your machine to get access to credentials to different accounts (including cryptocurrency wallets). That spyware2 can extract your logins and passwords from your browser’s auto-filling data.

Often tamperers would decrypt few of your files to prove that they indeed have the decryption tool. Since Sigrun virus is a relatively new ransomware, security software developers have not yet found a method to undo its work. Nevertheless, the decryption instruments are frequently updated, so the effective countermeasure may soon be available.

Of course, if the tamperers do the job of encoding victim’s essential data, the hopeless person will probably fulfill their demands. Nevertheless, paying to racketeers does not necessarily mean that you’re getting your data back. It is still dangerous. After obtaining the money, the racketeers may send a wrong decryption code to the victim. There were reports of racketeers just vanishing after getting the money without even writing back.

The optimal safety measure against ransomware is to have a system restore point or the copies of your essential files in the cloud storage or at least on an external storage. Surely, that might be not enough. Your most important thing could be that one you were working upon when it all happened. But at least it is something. It is also advisable to scan your drives with the anti-malware utility after the system is rolled back.

There are other ransomware products, besides Sigrun, that work similarly. For instance, Tury, Nuis, Adlg, and some others. The two basic differences between them and the Sigrun are the ransom amount and the encoding method. The rest is the same: documents become encoded, their extensions altered, ransom notes are created in each folder containing encrypted files.

Some fortunate people were able to decrypt the arrested files with the aid of the free software provided by anti-ransomware developers. Sometimes the criminals mistakenly send the decryption code to the wronged in the ransom note. Such an epic fail allows the user to restore the files. But of course, one should never expect such a chance. Make no mistake, ransomware is a tamperers’ tool to pull the money out of their victims.

How сan I avoid ransomware infiltration?

Sigrun ransomware has no superpower, neither does any similar malware.

You can armour your PC from its injection within three easy steps:

  • Ignore any emails from unknown mailboxes with strange addresses, or with content that has likely no connection to something you are expecting (can you win in a lottery without participating in it?). If the email subject is more or less something you are waiting for, scrutinize all elements of the suspicious letter carefully. A fake email will surely have mistakes.
  • Avoid using cracked or unknown software. Trojan viruses are often spreaded as an element of cracked software, possibly under the guise of “patch” which prevents the license check. Understandably, untrusted programs are difficult to distinguish from reliable software, because trojans may also have the functionality you seek. You can try to find information on this software product on the anti-malware message boards, but the optimal way is not to use such programs at all.
Reasons why I would recommend GridinSoft3

Download Removal Tool.

Run the setup file.

Run Setup.exe
GridinSoft Anti-Malware Setup

Press “Install” button.

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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

đŸ€” How can I open “.sigrun” files?Is it possible to open“.sigrun” files?

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

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

If the “.sigrun” files contain some really important information, then you probably have them backed up. In case you haven’t, there is still a chance that you do have a Restore Point from some time ago to roll back the whole system to the moment when it had no virus yet, but already had your files. All other solutions require time.

đŸ€” What to do if the Sigrun ransomware has blocked my PC and I can’t get the activation key.

đŸ€” What can I do right now?

Some of the encrypted files can be found elsewhere.

  • If you sent or received your important files by email, you could still download them from your online mailbox.
  • You may have shared images or videos with your friends or relatives. Just ask them to post those pictures back to you.
  • If you have initially downloaded any of your files from the Internet, you can try downloading them again.
  • Your messengers, social media pages, and cloud drives might have all those files as well.
  • It might be that you still have the needed files on your old PC, a notebook, cellphone, memory stick, etc.

HINT: You can use file recovery utilities5 to get your lost data back since ransomware blocks the copies of your files, deleting the authentic ones. In the video below, you can learn how to use PhotoRec for such a recovery, but remember: you can do it only after you kill the virus with an anti-malware 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

References

  1. Here are 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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