a800 Ransomware

Also Known As: a800 virus
Distribution: Low
Damage level: Severe

a800 ransomware removal instructions

What is a800?

There are many ransomware-type programs that cyber criminals use to encrypt data and blackmail people (make ransom demands). Note that a800, a new variant of RotorCrypt ransomware discovered by Michael Gillespie, is an example of one of these programs. This malicious program renames every encrypted file by adding the "!__help2decode@mail.com__.a800" extension. For example, "1.jpg" becomes "1.jpg!__help2decode@mail.com__.a800". Like most ransomware-type programs, a800 creates a ransom message - in this case, within a new text file called "recovery.instruction.txt".

In the "recovery.instruction.txt" ransom message, cyber criminals (a800's developers) inform victims that all files were encrypted using RSA-2048 cryptography algorithm. They explain that encrypted files can no longer be used (read, opened, or even identified). The only way to restore them is to seek their help by sending an email to the help2decode@mail.com address. It is very likely that any other details (such as cost of decryption and how to pay) are provided after contacting these cyber criminals. Most ransomware developers use cryptography algorithms that makes decryption without using a specific decryption tool impossible. Therefore, victims are encouraged to contact them and meet their demands by transferring ransoms sums in a cryptocurrency. Note, however, that most cyber criminals ignore victims after they receive payment. Therefore, they should not be trusted. Decryption cannot generally be performed without using tools available only to ransomware developers. Furthermore, there are no tools capable of decryption of files encrypted by a800 free of charge. The best option is this case (and in many other similar cases) is to use a data backup created before encryption and restore everything from there.

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

a800 decrypt instructions

Many cyber criminals proliferate ransomware-type programs. Some examples of other programs of this type are NWA, Yatron, and Plomb. In most cases, these computer infections are very similar - they encrypt data and display ransom demand messages. Common differences are usually cost of decryption tool/key and cryptography algorithm used for encryption. Unfortunately, most ransomware-type programs are "uncrackable" - encrypted files cannot be decrypted without contacting cyber criminals and using tools that only they can provide. decryption is only possible if the ransomware is not fully developed or contains bugs/flaws. Therefore, maintain regular backups and store them on remote servers or unplugged storage devices.

How did ransomware infect my computer?

It is unknown exactly how cyber criminals proliferate a800 ransomware, however, they use similar methods that include spam campaigns, Trojans, fake software updaters, untrustworthy software download sources, and software "cracking" tools. Spam campaigns distribute emails that contain malicious attachments - usually Microsoft Office documents, PDF files, executables (.exe files), archives (ZIP, RAR, and so on), JavaScript, or other files. The main purpose of these emails is to trick people into opening the attachments that, once opened, download/install ransomware or other infections. To proliferate these viruses, cyber criminals also use Trojans - malicious programs that proliferate other programs of this type, thus causing chain infections. Fake software updaters cause computer infections by downloading and installing malware rather than promised (expected) updates or fixes or by exploiting outdated software bugs/flaws. Untrustworthy software download sources such as freeware download websites, free file hosting websites, Peer-to-Peer networks (torrent clients, eMule, and so on), third party downloaders, and other such tools can be used to present malicious files as legitimate. In this case, cyber criminals attempt to trick people into downloading and installing computer infections. Software "cracking" tools allow people to bypass paid software activation free of charge. Cyber criminals often use this software to proliferate ransomware and other malicious programs.

Threat Summary:
Namea800 virus
Threat TypeRansomware, Crypto Virus, Files locker
SymptomsCan't open files stored on your computer, previously functional files now have a different extension, for example my.docx.locked. A ransom demanding message is displayed on your desktop. Cyber criminals are asking to pay a ransom (usually in bitcoins) to unlock your files.
Distribution methodsInfected email attachments (macros), torrent websites, malicious ads.
DamageAll files are encrypted and cannot be opened without paying a ransom. Additional password stealing trojans and malware infections can be installed together with a ransomware infection.

To eliminate a800 virus our malware researchers recommend scanning your computer with Spyhunter.
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Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

How to protect yourself from ransomware infections?

Avoid opening attachments or web links that are presented in e-mail messages received from unknown/untrustworthy suspicious addresses. If an email seems irrelevant (even if presented as legitimate and official), it should not be trusted without carefully studying it first. Download software using official, trustworthy sources (websites) and direct links. Third party downloaders, Peer-to-Peer networks such as torrents, eMule, dubious/unofficial websites should not be used. Software should be updated using tools or implemented functions that are provided by official developers only (not third party tools). Note that software "cracking" tools cause computer infections and are also illegal. Have reputable anti-spyware or anti-virus software installed and enabled at all times. These programs can detect and remove viruses before they can do any damage to the computer or operating system. If your computer is already infected with a800, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Text presented in a800 ransomware text file ("recovery.instruction.txt"):

What happened to your files ?
All of your files were protected by a strong encryption with RSA-2048.
More information about the encryption keys using RSA-2048 can be found here:

What does this mean ?
This means that the structure and data within your files have been irrevocably changed,
you will not be able to work with them, read them or see them, it is the same thing as
losing them forever, but with our help, you can restore them.

CONTACT US BY EMAIL: help2decode@mail.com

Screenshot of files encrypted by a800 (adding the "!__help2decode@mail.com__.a800" extension):

Files encrypted by a800

a800 ransomware removal:

Instant automatic removal of a800 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 a800 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 a800 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 a800 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 a800 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 a800 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 a800, 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 EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as a800 ransomware.

Note that Windows 10 Fall Creators Update includes a "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default, this feature automatically protects files stored in the Documents, Pictures, Videos, Music, Favorites as well as Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here is more information on how to get this update and add an additional protection layer from ransomware infections.

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 a800 ransomware: