Trojan:vbs/mutuodo.a: what it is and how to remove it
Trojan:vbs/mutuodo.a is a malicious file that is recognized as a Trojan horse by most of the reputable AV-Engines. It's a hazardous cyber infection, which is related to Win32/Prifou family of Trojans and PriceFountain adware.
Facts checked October 7, 2026. Removal steps tested on Windows 11 (26H2) and checked against Microsoft's and the browser makers' current documentation. Sections marked as our earlier report are the original text: they describe the threat as it was then and have not been reviewed since. The 2026 status, the removal steps and the questions are current.
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Trojan:vbs/mutuodo.a: summary
| Detection names | No Microsoft detection name is known |
|---|---|
| Distribution | Not recorded in the old report |
| Damage | Not recorded in the old report |
| Name | Trojan:vbs/mutuodo.a |
| Type | Loader |
| Symptoms | An unknown process in Task Manager |
| Removal | Scan the PC with security software to find and remove the malware and anything installed with it. Fortect scans Windows for malware and repairs the system files and settings it damaged. Remove it nowTo use the full-featured product, you have to purchase a license for Fortect. The scan is free. |
Show 4 more facts
| Evidence | 4 write-ups by security sites; details still limited |
|---|---|
| File names | Prifou.exe and %APPDATA%\PriceFountain\UpdateProc\bkup.dat |
| First seen | 9 April 2018 |
| Facts checked | 7 October 2026 |
What Trojan:vbs/mutuodo.a does on an infected PC
From our report of Apr 2018 · not reviewed since
Trojan:vbs/mutuodo.a is a malicious Trojan horse related to PriceFountain adware
Trojan:vbs/mutuodo.a is a malicious file that is recognized as a Trojan horse by most of the reputable AV-Engines.
It's a hazardous cyber infection, which is related to Win32/Prifou family of Trojans and PriceFountain adware.
Mutuodo Trojan is extremely dangerous. Cybersecurity experts from lesvirus.fr initiated an in-depth analysis of its capabilities. According to them, the PriceFountain, an infamous adware program, might be infected with Mutuodo virus and once installed run Win32/Prifou.exe, wscript.exe, UpdateTask.exe, and other malicious scrips.
Upon successful infiltration, the Mutuodo Trojan virus attempts to root deeply into the operating system. It creates new registry entries and may try to modify the existent ones. These are a few Mutuodo virus related registry entries:
Additionally, it injects malicious script into System's folder %APPDATA% by running the following commands:
All these changes are initiated to set PriceFountain value. This application is known for displaying intrusive online advertisements within web browsers, track people's web browsing activities, and initiate other intrusive activities without authorization.
Nevertheless, mutuodo trojan along with PriceFountain or any other PUP might turn out to be extremely malicious. Recently, several people reported that the infiltration of this Trojan ended up with a total system's hijack since the Trojan managed to compromise Microsoft account's password. It can open a backdoor to other malicious infections, such as Spyware, Worm or even Ransomware.
To protect your PC from damage, remove Trojan:vbs/mutuodo.a virus from the system. Keep in mind that it's not enough to delete PriceFountain or other PUPs related to the Trojan. It's a must to stop all malicious processes and immunize the Trojan itself.
Although Trojans, unlike other cyber infections, do not reproduce by infecting other system's files nor do they self-replicate, they seek to open the backdoor on the targeted system and this way give the malicious user access to the system, exposing confidential or personal data to the risk of being leaked.
Thus, an immediate Mutuodo is a must. Otherwise, the Trojan can cause irreversible damage to the system and the data stored on it.
From our report of Apr 2018 · not reviewed since
Trojan horse can enter the system in the form of a legitimate application
The name Trojan horse has been given to this infection not without reason.
Relating the name with the history of Troy implies that the Trojan as a virus refers to some program or file that does not look suspicious from the initial inspection. However, once it gets into the system, it initiates malicious activities and can be extremely dangerous.
While a reputable anti-virus might help to evade Trojan infections, new Trojans may not be recognized as threats. Outdated virus database may also be the reason why a malicious program bypassed the protection.
Trojan horses are usually distributed as hidden components of mini-games or torrent files. In many cases, they spread as stand-alone installers. Hackers may try to spread them in malicious spam email attachments, fake software updates, and similar means. Thus, make sure to keep your antivirus updated and avoid interference with suspicious content online.
From our report of Apr 2018 · not reviewed since
More from our earlier report on Trojan:vbs/mutuodo.a
- Windows Defender, Symantec, BitDefender, and other powerful security utilities name it Mutuodo Trojan or Mutuodo virus.
- Can cause a total system's crash, data corruption or leakage
- %LOCALAPPDATA%\{GUID}\synhelper.exe ({GUID} stands for the 32-digit hexadecimal number).
How to check the PC for Trojan:vbs/mutuodo.a
- Path:
%APPDATA%\PriceFountain\UpdateProc\bkup.dat - File:
Prifou.exe
How to remove Trojan:vbs/mutuodo.a
A loader's job is to install other malware, so treat the PC as infected with more than one program until the scans are clean.
Step 1: Check where Prifou.exe runs from and stop it
Prifou.exeis the part you can see, and its location tells you whether it belongs there. Right-click it on the Processes page of Task Manager and choose Open file location, then right-click the file > Properties > Digital Signatures to see who signed it.An unsigned file, or one in a user folder such as
%AppData%, is the one to remove: end the task, then delete the file.Note the folder name, because the same folder usually holds its other files. This is the same in Windows 11 and Windows 10.
Full procedure with screenshots: Close a frozen app (Task Manager, Force Quit) On uGetFix
Step 2: Delete scheduled tasks that bring it back
Open Task Scheduler from the Start menu and click Task Scheduler Library. Select each task you do not recognise and read the Actions tab:
- a task that starts a file in
%AppData%or%Temp% - runs
powershellwith a long encoded line - opens a web address belongs to Trojan:vbs/mutuodo.a or a similar program
Right-click such a task and choose Delete, and check the subfolders too. Leave tasks from Microsoft, your PC's maker and programs you use. Task Scheduler is the same in Windows 11 and Windows 10.
Windows 11: Task Scheduler Library, the task selected, the Actions tab shows the file it runs. Full procedure with screenshots: Remove what malware leaves behind in Windows
- a task that starts a file in
Step 3: Remove it from startup
Whatever Trojan:vbs/mutuodo.a installed usually starts with Windows. Open Task Manager with Ctrl + Shift + Esc, go to Startup apps in Windows 11 or the Startup tab in Windows 10, and disable what you do not know, starting with entries that have an empty Publisher column.
Open file location on the right-click menu shows the file, which helps you decide and tells you what to delete later. Disabling is safe: if something you need stops working, switch it back on.
Full procedure with screenshots: Stop apps from opening at startup On uGetFix
Step 4: Delete the folders left behind
What the uninstaller leaves behind is usually in the user folders. Open File Explorer, switch on View > Show > Hidden items (in Windows 10 View > Hidden items), and go through
%LocalAppData%,%AppData%, %ProgramData% and the two Program Files folders.Sort by Date modified and delete folders that appeared together with the problem and belong to no program you use. Folders with random names that hold
.exe,.dll, .js or .ps1 files are the strongest sign.Full procedure with screenshots: Remove what malware leaves behind in Windows
Step 5: Scan the PC, then run the offline scan
Open Windows Security > Virus & threat protection > Scan options, run a Full scan and remove everything it finds. Then select Microsoft Defender Antivirus (offline scan) and click Scan now: the PC restarts and scans before Windows loads, which finds files that hide while Windows runs.
Save your work first, because the offline scan takes about 15 minutes. Both scans are built into Windows 11 and Windows 10, and a second scanner from another vendor is a useful extra opinion.
Windows 11: Windows Security > Virus & threat protection > Scan options. Full procedure with screenshots: Run a Microsoft Defender Offline scan
Step 6: Change passwords from another device and sign out other sessions
Assume that the passwords saved in this PC's browsers, and the accounts that were open in them, are known to the attacker. From a phone or a clean computer, change the e-mail password first, then banking, shopping, social and gaming accounts.
Use each service's option to sign out of all other sessions, because stolen cookies keep a session open even after a password change. Turn on two-step verification on each account. Wait with the infected Windows 11 or Windows 10 PC until the scans are clean.
Full procedure with screenshots: Turn on two-step verification / secure a hacked account
Instructions for each browser and system
The detailed steps for every browser and system this guide covers. Open the one you use.
Manual removal using Safe Mode
Important! →
Manual removal guide might be too complicated for regular computer users. It requires advanced IT knowledge to be performed correctly (if vital system files are removed or damaged, it might result in full Windows compromise), and it also might take hours to complete. Therefore, we highly advise using the automatic method provided above instead.
Step 1. Access Safe Mode with Networking
Manual malware removal should be best performed in the Safe Mode environment.
Windows 7 / Vista / XP
- Click Start > Shutdown > Restart > OK.
- When your computer becomes active, start pressing F8 button (if that does not work, try F2, F12, Del, etc. - it all depends on your motherboard model) multiple times until you see the Advanced Boot Options window.
- Select Safe Mode with Networking from the list.
Windows 10 / Windows 8
- Right-click on Start button and select Settings.
- Scroll down to pick Update & Security.
- On the left side of the window, pick Recovery.
- Now scroll down to find Advanced Startup section.
- Click Restart now.
- Select Troubleshoot.
- Go to Advanced options.
- Select Startup Settings.
- Press Restart.
- Now press 5 or click 5) Enable Safe Mode with Networking.
Step 2. Shut down suspicious processes
Windows Task Manager is a useful tool that shows all the processes running in the background. If malware is running a process, you need to shut it down:
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Click on More details.
- Scroll down to Background processes section, and look for anything suspicious.
- Right-click and select Open file location.
- Go back to the process, right-click and pick End Task.
- Delete the contents of the malicious folder.
Step 3. Check program Startup
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Go to Startup tab.
- Right-click on the suspicious program and pick Disable.
Step 4. Delete virus files
Malware-related files can be found in various places within your computer. Here are instructions that could help you find them:
- Type in Disk Cleanup in Windows search and press Enter.
- Select the drive you want to clean (C: is your main drive by default and is likely to be the one that has malicious files in).
- Scroll through the Files to delete list and select the following:
Temporary Internet Files
Downloads
Recycle Bin
Temporary files - Pick Clean up system files.
- You can also look for other malicious files hidden in the following folders (type these entries in Windows Search and press Enter):
%AppData%
%LocalAppData%
%ProgramData%
%WinDir%
After you are finished, reboot the PC in normal mode.
From our report of Apr 2018 · not reviewed since
Remove Mutuodo Trojan easily
Mutuodo removal is a complicated process, which has to be initiated in phases.
First of all, Trojan-related processes have to be disabled, and the main executable file immunized. Subsequently, the related components and corrupted Windoęws Registry entries have to be eliminated.
To remove Mutuodo Trojan from the system entirely, it's a must to use a professional anti-malware program. In fact, there's no other way to get rid of this infection except to get rid of it using , , or similar anti-malware tool. Manual removal is not only impossible, but an attempt to eliminate malicious files can cause even more damage to the system.
If Mutuodo virus blocks the anti-virus and you cannot launch it or download another security tool, follow the instructions provided below to boot the system into Safe Mode with Networking:
[GI=method-1]If you cannot get rid of a Trojan horse because it blocks your security tool, try to launch if after booting the system into Safe Mode with Networking:
[GI=method-2]If the previous method did not help to get rid of Trojan:vbs/mutuodo.a virus, try these steps:
After removal: passwords, accounts and prevention
Your passwords after Trojan:vbs/mutuodo.a
Removing Trojan:vbs/mutuodo.a does not undo what it may already have sent out while the PC showed an unfamiliar process called Prifou.exe in Task Manager.
Treat saved browser passwords and logged-in sessions on this PC as known to the attacker.
From another device, change the e-mail password first and end all its sessions. Then do the same for the bank, PayPal, Microsoft, Google and Apple accounts. Stolen session cookies keep working after a password change until you sign out everywhere.
Move crypto to a new wallet created on a clean device. A step-by-step order for every kind of account is in our guide to account security after an infection.
Access your website securely from any location
When you work on the domain, site, blog, or different project that requires constant management, content creation, or coding, you may need to connect to the server and content management service more often. The best solution for creating a tighter network could be a dedicated/fixed IP address.
If you make your IP address static and set to your device, you can connect to the CMS from any location and do not create any additional issues for the server or network manager that needs to monitor connections and activities. VPN software providers like can help you with such settings and offer the option to control the online reputation and manage projects easily from any part of the world.
Recover files after data-affecting malware attacks
While much of the data can be accidentally deleted due to various reasons, malware is one of the main culprits that can cause loss of pictures, documents, videos, and other important files.
More serious malware infections lead to significant data loss when your documents, system files, and images get encrypted. In particular, ransomware is is a type of malware that focuses on such functions, so your files become useless without an ability to access them.
Even though there is little to no possibility to recover after file-locking threats, some applications have features for data recovery in the system. In some cases, can also help to recover at least some portion of your data after data-locking virus infection or general cyber infection.
Questions about Trojan:vbs/mutuodo.a
What is Prifou.exe and why is it running?
Every process is started by something:
- a program you installed
- a Windows service
- a scheduled task
- a startup entry
To learn why Prifou.exe runs, find its file with Open file location in Task Manager, then look for an entry pointing to that file in Settings > Apps > Startup and in Task Scheduler.
Sort Installed apps by date to see what arrived when the process first appeared. Once you know the owner, you can decide whether to keep it, switch it off at startup or uninstall it completely.
Can I delete the Prifou.exe file?
Only after you know what it belongs to. If Prifou.exe is part of a program, uninstall that program through Settings instead, so its services and tasks go too. If it belongs to nothing and is unsigned, end the process, disable whatever starts it and then delete its folder.
Do not delete files from the Windows folder or files signed by Microsoft: those are part of the system, and removing them can stop Windows from starting. When in doubt, run a Microsoft Defender scan first and let it decide.
Can I just delete Prifou.exe?
Deleting Prifou.exe by hand rarely removes Trojan:vbs/mutuodo.a. While the trojan runs, Windows may refuse to delete the file, and if you succeed, a scheduled task, a service or a second copy may bring it back at the next restart.
The file can also be only one part of the infection: loaders and remote access tools often install other programs. Use the Microsoft Defender offline scan, which removes the file together with its startup entries before Windows loads, and then check startup items and scheduled tasks as described in the plan.
Is Trojan:vbs/mutuodo.a a known trojan?
Not as a documented family, at least not yet. What is known is the visible sign, an unfamiliar process called Prifou.exe in Task Manager, which matches a hidden program working for someone else.
New threats are often seen by victims weeks before researchers publish anything about them. Treat Trojan:vbs/mutuodo.a as you would any trojan:
- remove what starts it
- run an offline scan
- change passwords from another device
If a scan reports a detection name, keep it; it usually reveals the family and whether it is known to download other malware. We update this guide when an analysis appears.
Why didn't my antivirus stop Trojan:vbs/mutuodo.a?
New trojan builds are packed and changed often so that signatures do not match, and some are signed with stolen or bought certificates. Many arrive inside password-protected archives, which scanners cannot open until you extract them.
Some downloads also tell the user to turn off the antivirus "because it gives false alarms", a common line in cracked software instructions. Keep real-time protection on, never disable it for an installer, and run the offline scan whenever you suspect something slipped through.
How dangerous is Trojan:vbs/mutuodo.a?
Treat it as serious until proven otherwise. The visible sign is an unfamiliar process called Prifou.exe in Task Manager, and programs that behave this way often have more abilities than they show:
- copying passwords
- downloading other malware
- giving remote access
Its family is not known yet, so nobody can say which of these it uses. The good news is that the response is the same in every case and takes about an hour:
- cut the network
- remove the startup entry
- run an offline scan
- change passwords from a clean device
If someone had remote control, a full reset is safer.
Is a trojan infection worth reporting to the police?
If there was harm, yes. Unauthorised payments, accounts used for fraud, blackmail or a remote session during a scam call all belong in a report, and banks often ask for its reference number before they refund anything.
If antivirus caught Trojan:vbs/mutuodo.a before it ran and nothing was misused, there is nothing to report. Keep the evidence anyway:
- protection history
- the original download
- the dates
Businesses may also have to notify a data protection authority if personal data could have been accessed.
What are the signs of a trojan infection?
Most trojans try to leave no visible signs, so look for side effects. Common ones:
- Windows Security turned off or unable to update
- new entries in Startup apps or Task Scheduler
- programs in Installed apps you did not install
- browser settings that changed by themselves
- unusual network activity while the PC is idle
- password-reset or login-alert e-mails you did not trigger
None of these proves an infection on its own. Together with an antivirus alert naming Trojan:vbs/mutuodo.a, they are a strong reason to follow the full plan.
Can a normal remote support program be a backdoor?
Yes. Tools such as AnyDesk, TeamViewer and ScreenConnect are legitimate, but whoever controls the account behind them controls the PC. Scammers install them during fake support calls, and some trojan campaigns install them silently because antivirus programs do not flag a genuine, signed product.
If you find one you did not set up, uninstall it, check Startup apps for related entries and change passwords from another device. If money or accounts were involved, call your bank and report the incident.
Will Fortect remove Trojan:vbs/mutuodo.a?
Fortect scans Windows for malware and unwanted programs and repairs the system files and settings they change, and its free scan shows what it finds on your PC before you decide anything.
For Trojan:vbs/mutuodo.a, follow the plan above as well: the browser steps take back permissions and settings that no scanner treats as a threat, and uninstalling the program that brought it removes the source.
Run Microsoft Defender's full scan and, if anything was found, its offline scan as a second opinion. If the symptoms are gone after the plan and both scans are clean, there is nothing more to do.
Sources
- Lesvirus: Lesvirus (read October 7, 2026)
- Reddit: Win 10 pc infected by: trojan:VBS/Mutuodo.A (read October 7, 2026)
- FTC: How to recognize, remove and avoid malware (read October 7, 2026)
- Microsoft Learn: Microsoft Defender Offline (read October 7, 2026)
- Microsoft Learn: How Microsoft names malware (read October 7, 2026)