Remove Sigma Ransomware - Restore Files

Remove Sigma Ransomware – Restore Files

This article will aid you to remove Sigma ransomware completely. Follow the ransomware removal instructions given below in the article.

Sigma is a ransomware virus that encrypts your files. The Sigma virus displays a ransom note message stored in a file called ReadMe.html. You are demanded to pay 1000 US dollars in the Bitcoin cryptocurrency as a ransom to supposedly restore your data. Keep on reading below to see how you could try to potentially recover some of your files.

Threat Summary

TypeRansomware, Cryptovirus
Short DescriptionThe ransomware encrypts files on your computer and demands a ransom sum to be paid in the Bitcoin cryptocurrency.
SymptomsThe ransomware will encrypt your files, and also put up a ransom note called ReadMe.html.
Distribution MethodSpam Emails, Email Attachments
Detection Tool See If Your System Has Been Affected by Sigma


Malware Removal Tool

User ExperienceJoin Our Forum to Discuss Sigma.
Data Recovery ToolWindows Data Recovery by Stellar Phoenix Notice! This product scans your drive sectors to recover lost files and it may not recover 100% of the encrypted files, but only few of them, depending on the situation and whether or not you have reformatted your drive.

Sigma Ransomware – Distribution

Sigma ransomware might distribute its infection with various methods. A payload dropper which initiates the malicious script for this ransomware is being spread around the World Wide Web, and researchers have gotten their hands on a malware sample. If that file lands on your computer system and you somehow execute it – your computer system will become infected. You can see the detections of such a file on the VirusTotal service right here:

Sigma ransomware might also distribute its payload file on social media and file-sharing services. Freeware which is found on the Web can be presented as helpful also be hiding the malicious script for the cryptovirus. Refrain from opening files right after you have downloaded them. You should first scan them with a security tool, while also checking their size and signatures for anything that seems out of the ordinary. You should read the tips for preventing ransomware found in the forum section.

Sigma Ransomware – Description

Sigma is a virus that encrypts your files and extorts you to pay a ransom to supposedly recover them. The ransomware seems very similar to the LockeR Ransomware virus.

The extortionists want you to pay in Bitcoin for the alleged restoration of your files.

The following domain which is hosted on the TOR network is associated with the Sigma ransomware:

  • http://yowl2ugopitfzzwb(.)onion

Sigma ransomware might make entries in the Windows Registry to achieve persistence, and could launch or repress processes in a Windows environment. Such entries are typically designed in a way to launch the virus automatically with each start of the Windows Operating System.

That ransom note message is displayed after the encryption of your files is complete. It is inside a file named ReadMe.html and can be viewed from the following screenshot down here:

That note reads the following:

What has happened to my files ? Why i am seeing this ?

All of your files have been encrypted with RSA 2048 Encryption. Which means, you wont be able to open them or view them properly. It does NOT mean they are damaged.


Well its quite simple only we can decrypt your files because we hold your RSA 2048 private key. So you need to buy the special decryption software and your RSA private key from us if you ever want your files back. Once payment is made, you will be given a decrypter along with your private key , once you run that , All of your files will be unlocked and back to normal.

So there are 2 ways to do this either you wait for a miracle and get your price doubled or follow instructions below carefully and get back your all important files.

Payment procedure

Download a special browser called “TOR browser” and then open the given below link. Steps for the same are –

1. Go to to download the “TOR Browser“.
2. Click the purple button which says “Download TOR Browser”
3. Run the downloaded file, and install it.
4. Once installation is completed, run the TOR browser by clicking the icon on Desktop.
5. Now click “Connect button”, wait a few seconds. and the TOR browser will open.
6. Copy and paste the below link in the address bar of the TOR browser.


Now HIT “Enter”

7. Wait a few seconds. and site will open then enter your GUlD mentioned below and process.

The note of the Sigma ransomware states that your files are encrypted. You are demanded to pay 1,000 US dollars in the Bitcoin cryptocurrency and it will double after a deadline passes. However, you should NOT under any circumstances pay any ransom. Your files may not get recovered, and nobody could give you a guarantee for that. Moreover, giving money to cybercriminals will most likely motivate them to create more ransomware viruses or commit different criminal acts.

The screenshot below shows the payment page hosted on the TOR network:


Sigma Ransomware

Your documents, photos, databases and other important files have been encrypted

Your files were encrypted at Jan 1 1970 4:00 AM

To recover them you need the private key of the key pair used to encrypt them and the decryptor software.
You can buy both of them for $1000.00

Within 7 days you can purchase this product at a special price: ≈ $1000

After 7 days the price of this product will increase up to: ≈ $2000

Final deadline is 08-01-2018 01:12:17 (after that you will loose your important files forever)

1) Register a bitcoin wallet.

Create a Bitcoin Wallet (we recommend Blockchain(.)info) or other wallets (click here)

2) Purchase the required amount of bitcoins.

There are several ways you can buy bitcoins, you can use bitcoin exchanges (click here), buy directly from people
selling near you (click here) or using a bitcoin ATM (click here)

3) Send exactly $1000.00 to the address:


From that same page you can find the FAQ page which is shown down here:

Here is what that FAQ page reads:

Question: How can i decrypt my files after payment?

Answer: After payment, you can download the << Sigma Decryptor >> from your personal page. We guarantee that all your files will be decrypted!

Question: My files was infected more then month ago, can i still decrypt it with your software?

Answer: Yes, you can still decrypt your files after the payment we keep your keypair for 2 months then its gets delte automatically and its impossible to recover your files after that!

Question: I do have multiple computers infected is there any discount?

Answer: Please follow instructions mentioned on live chat page and connect with us we can negotiate for multiple computers

Question: So if i pay and get my files back am i secure in future from this ransomware ?

Answer: we sale special Immunity as low as 100$ more on top of the decrypter payment if you buy it , we add your machine GUID to our whitelist and in future your machine never ever get infected again for buying immunity please follow instructions mentioned on live chat page and connect with us !

To top it all off, below you can see the Desktop background which is changed from the Sigma ransomware:

The message on that picture is different than the ransom note and TOR pages, and reads this:




The only way to get back your files to normal is to receive the private key and decryption program

To receive the private key and decryption program we created files with complete instructions inside every folder of your computer

as we! as in your desktop named *README* please read it and follow

If you somehow can not find any *README* files at your PC, follow the instructions below

Download “Tor Browser” from and install it

In the “Tor Browser” open your personal page and enter your id : C912609086DF04DD92BB45751A16121C


Attention… this page is available via “Tor Browser” only

Sigma Ransomware – Encryption

There is not much known for the encryption process of the Sigma ransomware, except that the encryption algorithm used by the virus is RSA with 2048-bit ciphers and that files get encrypted with a random extension.

The targeted extensions of files which are sought to get encrypted are currently unknown and if a list is discovered, it will be posted here as the article gets updated. The files used most by users and which are probably encrypted are from the following categories:

  • Audio files
  • Video files
  • Document files
  • Image files
  • Backup files
  • Banking credentials, etc

The Sigma cryptovirus could be set to erase all the Shadow Volume Copies from the Windows operating system with the help of the following command:

→vssadmin.exe delete shadows /all /Quiet

If the above-stated command is executed that will make the encryption process more efficient. That is due to the fact that the command eliminates one of the prominent ways to restore your data. If your computer device was infected with this ransomware and your files are locked, read on through to find out how you could potentially restore your files back to normal.

Remove Sigma Ransomware and Restore Files

If your computer got infected with the Sigma ransomware virus, you should have a bit of experience in removing malware. You should get rid of this ransomware as quickly as possible before it can have the chance to spread further and infect other computers. You should remove the ransomware and follow the step-by-step instructions guide provided below.

Several computer victims that have been infected with the reason have actually paid the hackers. Following the payment that have received no decryptors or restore instructions which further backs up the fact that the ransom note is a scam. Victims of the virus are advised to follow our in-depth instructions.

Berta Bilbao

Berta is a dedicated malware researcher, dreaming for a more secure cyber space. Her fascination with IT security began a few years ago when a malware locked her out of her own computer.

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