How to remove Avos2 Ransomware

Offered on this article is a brief description of Avos2 ransomware virus. Also part of the page are Removal Guide, possible File Recovery of encrypted files, and Ways to Protect the Computer.

Avos2 ransomware is a notorious computer virus that arises from the clan of AvosLocker. Several antivirus programs may detect this threat as Doina, ZenaF, FileCoder, and Cryptor. Attackers designed Avos2 ransomware with the sole objective of encrypting crucial files on the computer. Once the victims were locked out of their files, the virus starts to demand ransom payment in order to restore the data to its original form. Aside from using a sophisticated encryption technique, the ransomware appends .avos2 file extension. As a result, the usual file abc.doc will become abc.doc.avos2.

How do Avos2 virus spreads?

Each piece of ransomware has the ability to spread worldwide. The action actually depends on how the attackers are going to deliberately deploy it over the internet. It can target users and organization anywhere in the world, or simply aim on the specific geographical area. The same can be said of the Avos2 ransomware. Like Rigd, Quantum, and AtomSilo, this threat can reach the computer in various methods, but the most effective phishing email is in force and the virus could reach thousands of inboxes in a single day.

By using the spam mass mail campaign, the virus is incorporated into the email and stands as a legitimate document. It contains an attractive message that can lure the recipients to open the attachment file, which generally entitled payment method, taxation, product inquiry, shipping, parcel delivery, and similar. Once the attached file is run by the user, Avos2 instantly launches the infection vector which generally starts by dropping the virus copy on the Windows system folder and other vital locations.

Dubious freeware, cracked software, serial key generator, or fake software upgrades are few executable files which easily launch the Avos2 ransomware infection on the computer. Typically, users actively download such types of programs from malicious websites and pop-up ads. Once run, it initiates the infection and soon it starts performing dangerous actions on the computer.

Avos2 file decryption

After the activation of the virus using the methods as stated above, it communicates to a remote server to download additional component. Then, it searches the drive or network resources for target files. After the scouting session of Avos2 ransomware, it starts encrypting the files to deny the access of users. To further make the data inaccessible, this virus is going to rewrite it with an added .avos2 file extension.

Avos2 ransomware informs the computer user about the attack by leaving a ransom note file containing specific information, especially ways to decrypt the inaccessible data. Below is the screen capture of the ransom note.

Avos2

Technical Details
Threat NameAvos2 Ransomware, AvosLocker
Threat TypeCrypto-virus, File Locker, Encryption Virus
Encryption MethodAES-256 combined with RSA-1024 Asymmetric Encryption
File Extension.avos2
Ransomware Note FileGET_YOUR_FILES_BACK.txt
Discovered by@fbgwls245
Virus AliasAd-Aware : Gen:Variant.Doina.23104
Avast : Win32:MalwareX-gen
Emsisoft : Gen:Variant.Doina.23104 (B)
ESET-NOD32 : A Variant Of Win32/Filecoder.OHU
Fortinet : W32/Filecoder.OHU!tr
GData : Gen:Variant.Doina.23104
Kaspersky : HEUR:Trojan-Ransom.Win32.Cryptor.gen
Malwarebytes : Malware.AI.3293914824
McAfee : RDN/Ransom
Panda : Trj/Genetic.gen
Sophos : Mal/Generic-S
Symantec : ML.Attribute.HighConfidence
TrendMicro : Possible_SMAVOSLOCKERTHA
VBA32 : BScope.TrojanRansom.Cryptor

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 Avos2 encrypted files right now.

Avos2 Ransomware Removal Guide

First thing to do is remove the Avos2 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 Avos2 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 Avos2 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.

CC for Windows Installation

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 Avos2, click on the Start Scan button. Wait for this scan to finish.

CC for Windows Start Scan

7. At the end of the scan process, click on Remove all threats to delete Avos2 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 Avos2 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 Avos2 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 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 Avos2 virus. Aside from our suggested tool, you may also run your own security program.

To remove Avos2 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 Avos2.

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.

Screenshot of Sophos EULA Page

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 Avos2 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 Avos2 and other suspicious entities. Be sure to remove all identified threats.

Screenshot of Sophos Virus Scan

The above procedures should have totally eliminated Avos2 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.

Download MSRT

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 Avos2 ransomware. Another option is to browse the location folder and double click on the file to run.

MSRT Icon

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.

MSRT Welcome

5. Next, you will see Scan Type. Please choose Full Scan to ensure that all Avos2 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.

MSRT 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.

MSRT Scan

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 Avos2 ransomware have been completely deleted from the computer. Please restart Windows to proceed with the normal operation.

Recover Files from Avos2 Ransomware Infection

On this section, we will provide ways to decrypt files infected with Avos2 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 Avos2 infected files with Emsisoft Tools

This service from Emsisoft is helpful in unlocking encrypted files without paying the ransom. It gives three ways to detect the ransomware and provide suitable recovery method:

Upload ransom note – This is usually the .txt or .hta files that was generated by Avos2 ransomware.

Upload the encrypted file – The actual encrypted file. Choose the one that is less than 8MB in size.

Contact information – Enter the email address or any links provided as it appears in the ransom note of Avos2 virus.

Emsisoft Tools

After submitting any of the appropriate data, Emsisoft will attempt to identify the ransomware and provide keys if there are available.

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 Avos2 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 Avos2. Instead, it restores files from backup copy.

Option 2: Use ShadowExplorer to restore files encrypted by Avos2 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 Avos2 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 Avos2 ransomware infection.

shadow3

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 Avos2 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 Avos2 ransomware was able to infect the computer. To minimize the possible infection, staying away from the common sources of this virus is crucial.

How Avos2 ransomware can infect your computer?

The method of infecting the computers was found to be similar as other common viruses. Though, ransomware like Avos2 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, Avos2 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, Avos2 ransomware demands for ransom money as payment for the decryption tool. To further understand the attack scheme, we have included an infographic below.

Infographic image of ransomware attack stages
You can print, download, or share the infographic by clicking the image.

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 Avos2 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.

Virus and Threat Protection

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 Avos2 or any type of ransomware.

Controlled Folder Access

5. Click on Protected Folderslink to include additional folders. Make sure that folders where important files are located should be included in the list.

Add Protected Folder

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 Avos2. 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.

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