How to uninstall Covid21 malware
Written by Tomas Meskauskas on (updated)
What is Covid21?
Covid21 is coronavirus-themed malware that corrupts The Master Boot Record (MBR), the first sector on a startup drive that contains executable code operating as a loader for the operating system. In this way, Covid21 prevents users from accessing the Windows Operating System. It also changes the desktop wallpaper.
Commonly, attackers design malware such as Covid21 to display a ransom demand message with instructions about how to pay for a tool, which will supposedly restore access to the operating system, however, this particular malware does not display any ransom message - it displays an image of a character from Japanese manga with a message stating that "Windows is killed".
Note that, even if Covid21 did display a ransom demand message, there is no guarantee that attackers would provide tools to supposedly restore access to Windows.
| Name | Covid21 MBR Malware |
| Threat Type | MBR malware |
| Detection Names | Avast (Win32:Malware-gen), BitDefender (Dropped:Application.Joke.Blurscrn.A), ESET-NOD32 (A Variant Of Win32/KillMBR.NDS), Kaspersky (Trojan.Win32.DiskWriter.dtu), Microsoft (Trojan:Win32/Killmbr), Full List (VirusTotal) |
| Symptoms | Windows operating cannot be accessed, changed desktop wallpaper |
| Distribution methods | Infected email attachments, malicious online advertisements, social engineering, software 'cracks'. |
| Damage | Corrupted MBR (Master Boot Record) |
| Malware Removal (Windows) | To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. |
In summary, cyber criminals behind Covid21 do not demand to be paid or contacted and, for this reason, it is likely that this malware is still under development. It is also possible that an upgraded (ransom demand) version of Covid21 will be released in future.
It is unknown how the current Covid21 version is distributed, however, cyber criminals are likely to use a number of methods (described below).
How did Covid21 infiltrate my computer?
Malware (including ransomware) is usually distributed via malspam campaigns, unofficial software activation ('cracking') tools, Trojans, dubious file/software download sources, and fake software updating tools.
When cyber criminals attempt to distribute malware via malspam campaigns, they send emails that contain malicious attachments or download links for malicious files. Typically, they disguise their emails as official and important. If recipients open the attached file (or a file downloaded via a website link), they cause installation of malicious software.
Cyber criminals commonly attach executable files (.exe), archive files such as RAR, ZIP, PDF documents, JavaScript files and Microsoft Office documents to their emails. Software 'cracking' tools supposedly activate licensed software illegally (bypass activation), however, they often install malicious programs and do not activate any legitimate installed software.
Trojans are other rogue programs that can cause chain infections. I.e., when a Trojan is installed on the operating system, it can install additional malware.
Free file hosting websites, freeware download websites, Peer-to-Peer networks (e.g., torrent clients, eMule), unofficial websites, and third party downloaders are examples of other sources that are used to distribute malware. Cyber criminals disguise malicious files as legitimate and regular. When users download and open them, they inadvertently infect their computers with malware.
Fake software updating tools install malicious software rather than updates/fixes for installed programs, or they exploit bugs/flaws of outdated software that is installed on the operating system.
How to avoid installation of malware
Download software and files from official websites and via direct links. It is not safe to use torrent clients, eMule (or other Peer-to-Peer networks), third party downloaders, unofficial websites or other sources of this kind.
Avoid third party installers. Check "Advanced", "Custom" and other settings, and decline offers to download or install unwanted software. Do not click ads that are displayed on dubious websites, since they can open other untrusted websites or even cause unwanted downloads and installations.
Remove any unwanted, suspicious applications (extensions, add-ons, and plug-ins) that are installed on the browser. The same should be applied to programs of this kind that are installed on the operating system.
Regularly scan your computer with reputable antivirus or anti-spyware software and keep this software up to date.
If you believe that your computer is already infected, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.
Screenshot of Covid21 desktop wallpaper:
Instant automatic malware removal:
Manual threat removal might be a lengthy and complicated process that requires advanced IT skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
▼ DOWNLOAD Combo Cleaner
By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.
Quick menu:
- What is Covid21?
- STEP 1. Manual removal of Covid21 malware.
- STEP 2. Check if your computer is clean.
How to remove malware manually?
Manual malware removal is a complicated task - usually it is best to allow antivirus or anti-malware programs to do this automatically. To remove this malware we recommend using Combo Cleaner Antivirus for Windows.
If you wish to remove malware manually, the first step is to identify the name of the malware that you are trying to remove. Here is an example of a suspicious program running on a user's computer:
If you checked the list of programs running on your computer, for example, using task manager, and identified a program that looks suspicious, you should continue with these steps:
Download a program called Autoruns. This program shows auto-start applications, Registry, and file system locations:
Restart your computer into Safe Mode:
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.
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.
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.
Video showing how to start Windows 10 in "Safe Mode with Networking":
Extract the downloaded archive and run the Autoruns.exe file.
In the Autoruns application, click "Options" at the top and uncheck "Hide Empty Locations" and "Hide Windows Entries" options. After this procedure, click the "Refresh" icon.
Check the list provided by the Autoruns application and locate the malware file that you want to eliminate.
You should write down its full path and name. Note that some malware hides process names under legitimate Windows process names. At this stage, it is very important to avoid removing system files. After you locate the suspicious program you wish to remove, right click your mouse over its name and choose "Delete".
After removing the malware through the Autoruns application (this ensures that the malware will not run automatically on the next system startup), you should search for the malware name on your computer. Be sure to enable hidden files and folders before proceeding. If you find the filename of the malware, be sure to remove it.
Reboot your computer in normal mode. Following these steps should remove any malware from your computer. Note that manual threat removal requires advanced computer skills. If you do not have these skills, leave malware removal to antivirus and anti-malware programs.
These steps might not work with advanced malware infections. As always it is best to prevent infection than try to remove malware later. To keep your computer safe, install the latest operating system updates and use antivirus software.
To be sure your computer is free of malware infections, we recommend scanning it with Combo Cleaner Antivirus for Windows.
Outstanding!
▼ Show Discussion