How to remove foSTE ransomware

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

foSTE ransomware removal instructions

What is foSTE?

Discovered by Michael Gillespie, foSTE is high-risk ransomware that belongs to the GlobeImposter ransomware family. As with most ransomware infections, foSTE encrypts stored data, thereby rendering it unusable. Additionally, foSTE appends each filename with the ".foSTE" extension (hence its name). For example, "sample.jpg" is renamed to "sample.jpg.foSTE". As well as encrypting data, foSTE generates an HTML file ("how_to_back_files.html") and stores it on the desktop.

The new HTML file contains a ransom demand message stating that data is encrypted and can only be restored using a unique decryption tool. Unfortunately, this information is accurate. foSTE encrypts data using cryptography that generates a unique decryption key individually for each victim. Note that victims cannot access their keys, as they are stored on a remote server controlled by cyber criminals (foSTE's developers). Therefore, to receive their key (or rather a decryption tool with the key embedded within), each victim must pay a ransom. The cost is not specified - all details are provided via email, however, the size of ransom usually fluctuates between $500 and $1500. Criminals typically ask to submit payments using cryptocurrencies (e.g., Bitcoin, DASH, Monero, Ethereum, or others). Additionally, criminals offer free decryption of one file as 'proof' that they are capable of restoring data. Be aware, however, that cyber criminals often ignore victims, once payments are submitted. Therefore, do not pay the ransom, whatever the cost. By paying, you will simply  lose your money and support cyber criminals' malicious businesses. Unfortunately, there are no tools capable of cracking foSTE encryption and restoring data free of charge. Therefore, you can only restore everything from a backup.

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

foSTE decrypt instructions

There are hundreds of ransomware-type infections that share similarities with foSTE including BudakAdame, and Ims00ryPox - the list goes on. Most encrypt data and make ransom demands. Unfortunately, encryption is typically performed using algorithms such as RSA, AES, and others, that generate unique decryption keys. Therefore, unless the virus has bugs or flaws, manual decryption without developers' involvement is impossible. Infections such as foSTE present a strong case for maintaining regular backups, however, store them on a remote server (e.g., Cloud) or unplugged storage device (Flash drive, external hard drive or similar), since locally stored backups are compromised with regular files. Additionally, have several backup copies stored in different locations, since there is always the chance that servers/storage devices can be damaged.

How did ransomware infect my computer?

The way developers proliferate foSTE is currently unknown, however, these infections are typically proliferated using spam email campaigns, third party software download sources, trojans, and fake software 'cracks' and updaters. Cyber criminals employ spam email campaigns to send hundreds of thousands of deceptive emails. These typically contain malicious attachments and messages encouraging recipients to open them. Attachments are often presented as 'important documents' (e.g., invoices, receipts, bills, or similar) in attempts to give the impression of legitimacy and increase the chance of tricking recipients. Unofficial software download sources (freeware download websites, free file hosting sites, Peer-to-Peer [P2P] networks, etc.) are used to present malicious executables as legitimate software, thereby tricking users into manual download/installation of malware. Trojans are malicious applications designed to cause "chain infections". They stealthily infiltrate systems and inject them with additional malware. Fake software 'cracks'/updaters infect computers rather than activating/updating software. In summary, careless behavior and lack of knowledge of these threats are the main reasons for computer infections.

Threat Summary:
Name foSTE virus
Threat Type Ransomware, Crypto Virus, Files locker
Encrypted Files Extension .foSTE
Ransom Demanding Message how_to_back_files.html file
Cyber Criminal Contact fostecrypt@aol.com 
Detection Names Avast (Win32:Malware-gen), BitDefender (Generic.Ransom.GlobeImposter.3B789F5D), ESET-NOD32 (A Variant Of Win32/Filecoder.FV), Kaspersky (Trojan-Ransom.Win32.Purgen.mm), Full List Of Detections (VirusTotal)
Symptoms Cannot open files stored on your computer, previously functional files now have a different extension (for example, my.docx.locked). A ransom demand message is displayed on your desktop. Cyber criminals demand payment of a ransom (usually in bitcoins) to unlock your files.
Distribution methods Infected email attachments (macros), torrent websites, malicious ads.
Damage All 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.
Removal

To eliminate foSTE virus our malware researchers recommend scanning your computer with Spyhunter.
▼ Download Spyhunter
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?

Caution is the key to computer safety. Therefore, pay close attention during the download/installation/update processes and when browsing the Internet. Your programs should be downloaded from official sources only, preferably using direct download links. Keep installed applications/operating systems up-to-date, however, use only implemented functions or tools provided by the official developer. Third party downloaders/installers/updaters often include rogue apps, and thus these tools should not be used. Cracking installed applications is illegal (software piracy is a cyber crime) and most cracking tools are fake. Therefore, the risk of infection is extremely high. So, activating installed apps with third party/illegal tools should never be considered. All email attachments should be handled with care. Files/links that are irrelevant and those received from suspicious email addresses should never be opened. Have a legitimate anti-virus/anti-spyware suite installed and running at all times. This software can detect and eliminate malware infections before the system is damaged. If your computer is already infected with foSTE, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

The appearance of foSTE ransomware pop-up (GIF):

foSTE pop-up gif

Text presented within foSTE ransomware HTML file ("how_to_back_files.html"):

YOUR PERSONAL ID
-


ENGLISH
YOUR FILES ARE ENCRYPTED!
ALL YOUR IMPORTANT DATA HAS BEEN ENCRYPTED.

To recover data you need decryptor.
To get the decryptor you should:
Send 1 test image or text file fostecrypt@aol.com.
In the letter include your personal ID (look at the beginning of this document).

We will give you the decrypted file and assign the price for decryption all files
After we send you instruction how to pay for decrypt and after payment you will receive a decryptor and instructions We can decrypt one file in quality the evidence that we have the decoder.
Attention!

Only fostecrypt@aol.com can decrypt your files
Do not trust anyone fostecrypt@aol.com
Do not attempt to remove the program or run the anti-virus tools
Attempts to self-decrypting files will result in the loss of your data
Decoders other users are not compatible with your data, because each user's unique encryption key

Screenshot of files encrypted by foSTE (".foSTE" extension):

Files encrypted by foSTE

foSTE ransomware removal:

Instant automatic removal of foSTE 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 foSTE 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 foSTE 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 foSTE 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 foSTE 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 foSTE 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 foSTE, 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 foSTE 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 foSTE 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 pcrisk.com 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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Malware activity

Global virus and spyware activity level today:

Medium threat activity
Medium

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

QR Code
foSTE virus QR code
A QR code (Quick Response Code) is a machine-readable code which stores URLs and other information. This code can be read using a camera on a smartphone or a tablet. Scan this QR code to have an easy access removal guide of foSTE virus on your mobile device.
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Platform: Windows

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