Four ransomware is a computer virus that cyber scammers use to blackmail computer users and ask them for cash. The notorious Four ransomware is capable of penetrating the computer while employing different tactics, which take advantage of connected online computers. As usual, it randomly approaches the computer by email phishing while the Four ransomware virus pretends as precious attachment file. Other than this most favored spread method by attackers, Four ransomware is being distributed in the same manner as older variants like Pauq, Tomle, 4help, and so on. These viruses can reach the computer through malicious social media links, infected websites, pirated software, dubious shareware, fake software update, malicious online advertisements, and Trojan contamination.
Four Ransomware Infection
Once the computer user executes the virus code from any of the mentioned sources, there will be no visible sign of the infection. This lack of visible indicator is the reason why Four ransomware attack was able to freely perform various malevolent actions. The virus is able to conceal itself on the computer and operate without revealing any signs of its illegal doings, where in fact, it can accomplish different tasks before proceeding with the file encryption.
When unnoticed, Four ransomware may communicate with the command and control server to receive commands and download the appropriate public key. With the help of the obtained key, Four ransomware will start to encrypt the majority of the files of the computer user and it applies a very complex technique. The virus also changes the file name by inserting a set of strings, including unique username, email address of the attacker, and specific ransomware file name. To find an example, the regular file word.doc is changed to word.doc.id-(F68B4E1H).[lizardcrypt@msgsafe.io].four.
Due to complicated encryption, it would be impossible for anyone to recover files without some decryption software. Therefore, people behind Four ransomware will take this opportunity to demand payment from victims in exchange for the recovery tool and a private key that are both essential to restore the encrypted files back to their original format.
Ransom demand of Four ransomware authors is explained in the ransomware note file “FILES ENCRYPTED.txt“. The document also provides the principal information that victims need to communicate with attackers and request a copy of the Four ransomware decryption tool.
| Threat Name | Four Ransomware, Dharma, CrySis |
|---|---|
| Threat Type | Crypto-virus, File Locker, Encryption Virus |
| Encryption Method | AES-256 combined with RSA-1024 Asymmetric Encryption |
| File Extension | .id-(unique ID).[clizardcrypt@msgsafe.io].four |
| Ransomware Note File | FILES ENCRYPTED.txt |
| Attacker’s email | lizardcrypt@msgsafe.io |
| Discovered by | @JakubKroustek |
| Virus Alias | Ad-Aware : Trojan.Ransom.Crysis.E Avast : Win32:RansomX-gen Avira : TR/Dropper.Gen BitDefenderTheta : AI:Packer.D3B9457E1E Bkav Pro : W32.AIDetectGBM.malware.01 CAT-QuickHeal : Ransom.Crysis.A3 ClamAV : Win.Trojan.Dharma-6668198-0 Comodo : TrojWare.Win32.Crysis.D@6sd9xy DrWeb : Trojan.Encoder.3953 Emsisoft : Trojan.Ransom.Crysis.E (B) ESET-NOD32 : A Variant Of Win32/Filecoder.Crysis.P F-Secure : Trojan.TR/Dropper.Gen FireEye : Generic.mg.3d8e0d85865bf1b6 Fortinet : W32/Crysis.W!tr.ransom GData : Win32.Trojan-Ransom.VirusEncoder.A Kaspersky : Trojan-Ransom.Win32.Crusis.to Malwarebytes : Ransom.Crysis McAfee : Ransom-Dharma!3D8E0D85865B Microsoft : Ransom:Win32/Wadhrama!hoa NANO-Antivirus : Trojan.Win32.Filecoder.emdnxn Panda : Trj/GdSda.A Qihoo-360 : HEUR/QVM20.1.769F.Malware.Gen Sophos : ML/PE-A + Troj/Criakl-G SUPERAntiSpyware : Ransom.Crysis/Variant Symantec : Ransom.Crysis TACHYON : Ransom/W32.crysis.94720 Tencent : Trojan-Ransom.Win32.Crysis.a TrendMicro : Ransom.Win32.CRYSIS.SM VBA32 : TrojanRansom.Crusis ViRobot : Trojan.Win32.Ransom.94720.F |
Backup your files
One important step before proceeding with the procedures below is to backup your files. Ransomware are not the same. Each has its unique sets of payloads aside from encrypting the files with complex method. Others tend to delete the infected files after certain period, while others keep them concealed on hidden places. In addition, ransomware decryption tools are not guaranteed to be perfect, there are instances that files suffer from damages during the decryption process.
So, create a backup copy of your entire Four encrypted files right now.
Four Ransomware Removal Guide
First thing to do is remove the Four virus before attempting the decryption. Remember that as long as the ransomware is active, it will repeatedly encrypt the files on the compromised computer.
Infection of Four ransom virus is dangerous to the system because it can inject files that runs each time Windows starts. To prevent the malicious files from loading, Windows operating system must run with minimal process and it can be done through SafeMode With Networking.
Quick Fix - Scan the PC with Combo Cleaner for Windows
Combo Cleaner is a trusted PC security and optimization tool equipped with powerful virus and malware detection engine. This program can get rid of ransomware like Four through this procedure.
1. Download the application from the following page:
2. Save the file to your preferred location.
3. Double-click the downloaded file CCSetup.exe and install with the default settings.
4. At the end of the setup process, click Finish to run Combo Cleaner.
5. The tool will update the signature file, please wait for this process to complete.
6. To begin checking for threats like Four, click on the Start Scan button. Wait for this scan to finish.
7. At the end of the scan process, click on Remove all threats to delete Four ransomware including all malicious objects from the computer.
Free features of Combo Cleaner for Windows include Disk Cleaner, Big Files finder, Duplicate files finder, and Uninstaller. To use antivirus, privacy scanner, and to delete identified threats, users have to upgrade to a premium version.
Please continue with the succeeding removal procedures if your are comfortable to manually get rid of the threat and malicious items linked with it.
Stage 1 : Temporarily Disable System Restore on Windows OS
Because Four and relevant virus is capable of reinstating itself by exploiting the System Restore of Windows, we suggests that you temporary disable System Restore while executing the steps. This option is also helpful to effectively run a full scan on the computer.
Do not forget to enable back System Restore after completing the removal of Four ransomware. This feature is vital in reinstating the operating system to previous normal working condition in case of problems or conflicts occurs.Stage 2 : Start Windows in Safe Mode With Networking
Windows 10/11 Guide
1. Click on Windows logo and select Power icon when options pop-ups.
2. Select Restart from the options while pressing Shift key on the keyboard.
3. Choose an Option window will appear, select the Troubleshoot button.
4. On next window, please choose Advanced Option.
5. On Advanced Option window, click on Startup Settings and then, click Restart button to reboot the computer.
6. When Windows boot on Startup Settings, press function key F5 or number 5 on keyboard.
A simpler alternative for Windows 10 users is to scan the computer with Microsoft Defender Offline. This will run a virus scan in the recovery environment.
Windows 8 Guide
1. Click Windows Start icon at the lower left section of the screen.
2. Open Search window and type Advanced in the field. It will open General PC Settings.
3. Click on Advanced Startup and then, click on Restart Now button.
4. Once the computer starts in Advanced Startup option menu, select Troubleshoot.
5. Next, click on Advanced Options to reveal the next section.
6. Click Startup settings and then, click Restart button to boot the PC in Startup Settings.
7. Use function key F5 or number key 5 to Enable Safe Mode with Networking.
Stage 3 : Scan the Computer with Sophos Antivirus
Ransomware files are placed deeply into the system and on various locations, thus, thorough scanning is vital to totally remove Four virus. Aside from our suggested tool, you may also run your own security program.
To remove Four automatically, scanning the computer with this efficient anti-malware tool is suggested. This scanner does not just uncover known threats like viruses or malware, it is also effective in discovering hazardous ransomware like Four.
1. Download Sophos Virus Removal Tool from the link below. Save the file on your computer where you can easily access it.
2. Once the download completes, browse the location of the file. Double-click to run the program and begin the install process.
3. On first windows of installation wizard, click Next to continue. Then, it will display the program’s License Agreement. You need to Accept the terms in order to proceed. If Windows prompts for User Account Control, please click Yes to proceed.
4. On succeeding windows, click Next or Continue to carry on with the installation. After completing the installation process, Launch Sophos Virus Removal Tool.
5. Internet connection is required when running this virus scanner in order to download important updates. Make sure that everything is up-to-date to effectively remove Four ransomware and other relevant viruses.
6. Click the Start Scanning button to inspect the computer. This will check the system for presence of malicious objects, malware, and viruses. The tool reveals items that were found linked to Four and other suspicious entities. Be sure to remove all identified threats.
The above procedures should have totally eliminated Four ransomware. However, if you found that there are still remnants of the virus, please proceed to succeeding procedures below.
Stage 4 : Double-check with Microsoft's Malicious Software Removal Tool
1. Download the free scanner called Malicious Software Removal Tool.
2. The tool automatically checks the operating system and suggest appropriate download version. Click on Download button to begin. Save the file to a convenient location, preferably on Desktop.
3. After downloading the file, Windows will prompt that download has completed. Click Run to start scanning for Four ransomware. Another option is to browse the location folder and double click on the file to run.
4. The tool will display Welcome screen, click Next. Please note the message "This tool is not a replacement for an antivirus product." You must understand that this program is made specifically to find and remove malware, viruses, Trojans, and other harmful elements on the computer. It was not designed to protect the computer.
5. Next, you will see Scan Type. Please choose Full Scan to ensure that all Four ransom virus entities and other harmful files left on the computer will be found and removed. For advanced computer user, you can opt for Customized Scan, if there are other drives or folders you wanted to include in this scan.
6. Full scan may take a while, please wait for Malicious Software Removal Tool to complete the tasks. However, you may cancel the scan anytime by clicking on the Cancel button.
7. After scanning, the tool will reveal all identified threats. There may be other threats that our first scan fails to detect. Please remove/delete all detected items.
8. When removal procedure is complete, you may now close Malicious Software Removal Tool. We hope that Four ransomware have been completely deleted from the computer. Please restart Windows to proceed with the normal operation.
Recover Files from Four Ransomware Infection
On this section, we will provide ways to decrypt files infected with Four ransomware. Aside from dedicated decryption software and common tools, other options for file recovery are provided. As much as we can, we will update this area whenever there is new and more suitable decryption tool was made available.
Decrypting Four infected files with Emsisoft Tools
This service from Emsisoft is helpful in unlocking encrypted files without paying the ransom. The page provides the list of ransomware decryption tools. All you have to do is look for the specific tool and start recovering the Four encrypted file.
Option 1: Windows Previous Version Tool
Windows Vista and Windows 7 have a feature called Previous Versions. However, this tool is only usable if restore point was made prior to ransomware infection. To use this tool as "recovery option" for files encypted by Four virus, please follow these steps:
1. Open My Computer or Windows Explorer.
2. Right-click on the affected files or folders. From the drop-down list, please click on Restore previous versions.
3. New window will open display all backup copy of files and folders you wanted to recover. Choose the appropriate file and click on Open, Copy, or Restore. Restoring selected files overwrites the current locked files on the computer. The tool is not actually recovering files encrypted by Four. Instead, it restores files from backup copy.
Option 2: Use ShadowExplorer to restore files encrypted by Four Ransomware
Just like Previous Version tool, ShadowExplorer is taking advantage of shadow copy created by Windows. This tool allows you to retrieve older version of files before it was encrypted by Four ransomware.
1. Download ShadowExplorer from the official web site.
2. Install the program with the default settings.
3. The program should run automatically after installation. If not, double-click on ShadowExplorer icon.
4. You can see the drop-down list on top of the console. Please select proper drive and the most recent point-in-time shadow copies of files you wish to restore prior to Four ransomware infection.
5. Right-click on the Drive, Folder, or File you wish to restore and click Export...
6. Lastly, ShadowExplorer will prompt for location where you want to save the copy of recovered files.
How to protect the computer from Four ransomware?
After the removal of the ransomware, it is important to prevent similar incident from happening again. In order to protect the computer effectively, computer user must know how Four ransomware was able to infect the computer. To minimize the possible infection, staying away from the common sources of this virus is crucial.
How Four ransomware can infect your computer?
The method of infecting the computers was found to be similar as other common viruses. Though, ransomware like Four is seen to have efficient deployment via spam email messages, web injectors, malicious software installers, misleading online advertisements, and through another virus infection.
Once the virus is executed, it immediately infects the system. Then, Four ransomware communicates to remote server so that unique key can be generated for the specific computer. After acquiring the key, it starts to decrypt target files using a complex method that is almost unbreakable. On the last stage of the attack, Four ransomware demands for ransom money as payment for the decryption tool. To further understand the attack scheme, we have included an infographic below.
Securing the computer against ransomware attack
Do a Regular File Back-up - Always backup your data on a separate storage devices such as external hard drives, optical discs, or online backup services.
Keep Your Software Updated - Make sure that you have the latest software updates especially on the operating system. Recent updates often contain vital security patches to help protect the computer against all forms of threats.
Install a Security Program - Protect the computer with effective anti-virus application using efficient real-time scanning. Regularly run a complete scan to check the computer for presence of malware.
Protect your files with Controlled Folder Access (Windows 10)
For Windows 10 users, aside from protecting the computer using anti-virus or anti-malware programs, one way to protect against ransomware attack is by using Controlled Folder Access. This feature of Windows Defender Security Center may not prevent the Four ransomware infection, but it can protect the folder and files in general. Follow the steps to enable Controlled Folder Access in Windows 10.
1. Go to Windows 10 Taskbar and search for Windows Defender Security Center.
2. Open Windows Defender Security Center and click on Virus & Threat Protection icon.
3. On next window, please click on Ransomware Protection.
4. Under Controlled Folder Access section, switch the slider to On. That will enable the feature and protect the folder against Four or any type of ransomware.
5. Click on Protected Folderslink to include additional folders. Make sure that folders where important files are located should be included in the list.
Troubleshooting Guide
Certain programs maybe blocked by Controlled Folder Access feature. To fix the issue, simply have the specific program to be white listed.
1. Under Protected Folders, click Allow an app through controlled folder access.
2. Next, click the Add an allowed app and include the target executable file.
This Controlled Folder Access feature is one way to protect files against Four. Other important things to do in keeping files safe against ransomware is through early prevention like keeping programs updated, install an efficient security program, an do regular file backup on a separate media drive.
