ASN1 Ransomware

Also Known As: asn1 virus
Distribution: Low
Damage level: Severe

ASN1 ransomware removal instructions

What is ASN1?

First discovered by MalwareHunterTeam, ASN1 is a ransomware-type virus that stealthily infiltrates the system and encrypts stored files. Cyber criminals spread ASN1 via spam emails (malicious attachments). Following infiltration, ASN1 encrypts files using asymmetric cryptography, unlike other ransomware-type viruses, it does not rename encrypted files or append extensions. Following successful encryption, ASN1 opens a pop-up window and creates an HTML file ("!!!!!readme!!!!!.html"), placing it in each folder containing encrypted files.

The pop-up and HTML files contain an identical ransom-demand message stating that files are encrypted, and encouraging victims to visit a Tor website. The website contains a message stating that a ransom of 1 Bitcoin (currently, 1 Bitcoin is equivalent to ~$735) must be paid. Victims will then supposedly be provided with a private key used to decrypt their files. The payment must be submitted with five days, otherwise decryption keys are deleted permanently. Be aware that files encrypted using asymmetric cryptography can only be restored using a private key. Criminals store this key on a remote server and attempt to trick victims into paying for it. Be aware, however, that cyber criminals often ignore victims, despite submitted payments. Therefore, you are strongly advised to ignore all requests to pay. It is highly probable that paying will not deliver any positive result  and you will simply be scammed. Furthermore, you will support their malicious businesses. Unfortunately, there are no tools capable of restoring files encrypted by ASN1 ransomware. Therefore, you can only restore your files/system from a backup.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

ASN1 decrypt instructions

Updated ASN1 ransomware pop-up message:

asn1 ransomware updated pop-up

ASN1 shares similarities with dozens of other ransomware-type viruses such as *.zzzzz, Shade, Locky, etc. All encrypt files and make ransom demands. There are just two noticeable differences: 1) type of cryptography (symmetric/asymmetric) used, and; 2) cost of decryption. Ransomware is often distributed via third party software download sources (torrents, freeware download websites, free file hosting websites, etc.), infectious files attached to spam emails, fake software update tools, and trojans. Therefore, never download software from unofficial sources or open files received from suspicious/unrecognizable email addresses. Cyber criminals are capable of exploiting software bugs/flaws to infect the system - for this reason, keep your installed applications up-to-date and use a legitimate anti-virus/anti-spyware suite. The key to computer safety is caution.

Screenshot of ASN1 HTML file:

ASN1 decrypt instructions

Text presented within ASN1 pop-up and HTML file:

1. Download and install TOR browser (recommended) or use your standard browser.
2. Follow the link that was generated for you.
3. On the next page you will see a Bitcoin wallet to pay, after you pay, you will get the key for decrypting your files.
4. Highlight (CTRL + A) and copy (CTRL + C) the key in clipboard, decoding will start.
5. Please, do not open files during decryption - opened files can not be decrypted.

Updated ASN1 .html ransom demanding file:

asn1 ransomware updated html file

Text presented in this file:

Your computer is under attack. Each file has been encrypted. In order to restore them, please read the following instruction.
What do you need to know?
. You can not restore the files by yourself without our assistance. 1024 bit encryption key has been used. All files encrypted with TripleDES algorithm.
. We guarantee complete recovery. To prove it, you can choose any file in your computer and we can easily decrypt it.
. An interference into the process will lead to the data loss. We highly recommend you not to open the important files and we can not be held responsible for them.
What are you supposed to do in order to decrypt the system?
1. Download and install the TOR browser. The link can be obtained by clicking on the button "COPY LINK(Download TOR browser)".
t will take about 5 minutes to install it as any other browser.
2. Open the personal page in the TOR browser.
ou can get the link by clicking on the button "COPY LINK(Personal Link)".
3. On the personal page you can see an unique BitCoin wallet and the amount you are supposed to deposit.
itCoin is popular e-currency. There are more than 100 different ways you can buy BitCoin .
4. Deposit the required amount to BitCoin wallet.
nce payment is received and confirmed, your private key will appear on the page.
5. Copy paste the private key. Decoding process will start automatically.
elect the private key and then press "CTRL + C".
6. On the personal page you can ask for help in customer service.
or decryption our application must be running. If you do not see this text, so antivirus removed the application. Download and install it again on the personal page.
make sure to save the link for your personal page.

Screenshot of ASN1 website:

ASN1 decrypt instructions

Text presented within ASN1 website:

Your files were encrypted!
1(0) BTC -> 1QBrNs96QUFXaU22SJh77RSVQkdqyxwBDb (4:23:59:49)
For getting decryption key you must to pay amount, written above, to bitcoin address, written above. Amount in brackets indicates already paid amount. For buy bitcoin online, google it now. This page will refreshed every 120 seconds. If you already paid, please, wait for page refreshing.
If sofware was deleted, download it now . Absense of payment during next five days will double amount.
Chat with support now

Updated Tor website:

asn1 ransomware updated tor website

Text presented in this site:

Personal page
Remaining time is: 1:23:54:33 (after the time is expired, the required amount will be increased in 2 times)
The bitcoins left to be paid: 0.5 BTC
The wallet for the payment: 1BWxxj3QBZVpsXGuwY5ScnCkY5idTsXfop
ANY ATTEMPT TO REMOVE OR DAMAGE THIS CRYPTOLOCKER will lead to the loss of the private key and to the loss of your files.
To make sure that the files can be decrypted, you can decrypt any of the encrypted files for free.
To decrypt the file, follow the link Chat with support.
In the opened window click the Browse button, select the file to decrypt and click Send.
When you upload the page again, you will receive the link for downloading the decrypted file.
Download cryptolocker
Chat with support

Screenshot of files encrypted by ASN1:

ASN1 decrypt instructions

ASN1 ransomware removal:

Instant automatic removal of asn1 virus: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Spyhunter is a professional automatic malware removal tool that is recommended to get rid of asn1 virus. Download it by clicking the button below:
▼ DOWNLOAD Spyhunter By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the ASN1 virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the ASN1 ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining ASN1 ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of ASN1 are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by ASN1, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and Malwarebytes Anti-Ransomware, which artificially implant group policy objects into the registry to block rogue programs such as ASN1 ransomware.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove ASN1 ransomware:

About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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Removal Instructions in other languages
Malware activity

Global virus and spyware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

QR Code
asn1 virus QR code
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Platform: Windows

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