Mlsuc: what it is and how to remove it
Mlsuc is a backdoor trojan that provides attackers with unauthorized remote access to the compromised computer. The intruder can download and upload files, run applications, restart the computer, uninstall the backdoor, send out e-mail messages or certain notifications.
Facts checked October 6, 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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Mlsuc: summary
| Detection names | No Microsoft detection name is known |
|---|---|
| Distribution | Not recorded in the old report |
| Damage | Not recorded in the old report |
| Name | Mlsuc |
| Type | Loader |
| Symptoms | An unknown program in Installed apps |
| 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 3 more facts
| Evidence | 4 write-ups by security sites; details still limited |
|---|---|
| First seen | 2 August 2018 |
| Facts checked | 6 October 2026 |
What Mlsuc does on an infected PC
From our report of Aug 2018 · not reviewed since
Do not enter questionable channels on mIRC
Chatting program mIRC is one of the most downloaded applications in the world and gained immense popularity before modern social networking apps came into play.
To some degree, this application is still widely used. Therefore, if you still make use of mIRC, beware that joining unknown channels might result in malware infections. Thus, only visit the ones you trust.
You should also be very careful when you browse the internet. There are plenty of unsafe places on the internet, and hackers are inclined to use that to their advantage. For example, file-sharing sites (especially torrents) and infested with malicious executables that might be presented as cracked software.
Additionally, cracks and keygens are often infected with malware. Furthermore, beware of fake updates and other malicious ads that could be set up by crooks just to make users to install viruses with one click.
Finally, spam emails can often include attachments that can execute trojans. The attached documents can be disguised as legitimate .doc, .html, .txt, .zip and other files. To make users open the malicious attachment, cybercrooks often use social engineering skills to compose quite convincing phishing emails.
From our report of Aug 2018 · not reviewed since
More from our earlier report on Mlsuc
- mIRC, spam emails, malicious websites
- Rarely any, although users might notice software crashes, stop errors, slowdown of the computer, etc.
- Malware infection, personal data leak
What Mlsuc can steal or download
From our report of Aug 2018 · not reviewed since
Mlsuc is a backdoor trojan that provides attackers with unauthorized remote access to the compromised computer.
The intruder can download and upload files, run applications, restart the computer, uninstall the backdoor, send out e-mail messages or certain notifications. Trojans are one of the most dangerous types of malware, as they are difficult to detect due to the lack of signs and symptoms.
Additionally, Mlsuc virus infiltrates machines via mIRC (an internet relay chat for Windows) as soon as they enter the compromised channel. Furthermore, the malware can be obtained through unsafe websites, as a drive-by download or executed from a spam email attachment.
Upon infiltration, Mlsuc virus performs several changes to system settings. It modifies Windows Registry to gain persistence. It adds the following registry lines:
The modified settings allow Mlsuc to boot every time the operating system is launched. Unfortunately, to detect these changes users would have to enter the patch inside Registry Editor, and less computer-savvy individuals might have never encountered such a function before. Thus, using anti-malware tool to detect and remove Mlsuc virus is the best option.
Speaking of detection, users may rarely experience Mlsuc infection symptoms. According to security experts from lesvirus.fr, the virus might sometimes show these signs:
Mlsuc trojan allows hackers to gain remote access to victims' machines and perform actions that can compromise users' virtual safety, jeopardize normal computer operation and even install other malware. Bad actors can take screenshots, turn on the video camera, send out or receive files, reboot the PC and execute files.
Mlsuc can redirect users to spoofed banking websites to make victims to enter their credentials. Hackers can then obtain this information and use for money stealing or identity fraud. The virus also prevents users from accessing security sites, such as firewall or anti-virus domains.
All in all, we suggest you remove Mlsuc virus from your computer ASAP.
- Software crashes or freezes;
- Increased CPU usage;
- Stop errors (BSoD);
- Increased amount of advertisements;
- Overall computer slowdown.
How to remove Mlsuc
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: 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 Mlsuc 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 2: Remove it from startup
Whatever Mlsuc 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 3: 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 4: 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 5: 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 Aug 2018 · not reviewed since
Remove Mlsuc malware from your PC - use security software
As we already mentioned, Mlsuc removal might be complicated since users may not be aware of the virus infection.
Especially those who do not have security software installed are vulnerable. Therefore, use general precautions and have an anti-virus program with real-time protection function installed at all times.
Do not try to remove Mlsuc virus manually as you will fail. Only the most computer-savvy individuals can perform that task, and it is a lengthy process overall. Besides, a trusted anti-malware software can prevent most of the infections from entering your device in the first place.
[GI=method-1]If security software does not work properly in normal mode, access Safe Mode with Networking:
[GI=method-2]You can use System Restore for complete Mlsuc elimination:
After removal: passwords, accounts and prevention
Your passwords after Mlsuc
Removing Mlsuc does not undo what it may already have sent out while the PC showed mlsuc in the list of installed apps.
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.
Do not let government spy on you
The government has many issues in regards to tracking users' data and spying on citizens, so you should take this into consideration and learn more about shady information gathering practices.
Avoid any unwanted government tracking or spying by going totally anonymous on the internet.
You can choose a different location when you go online and access any material you want without particular content restrictions. You can easily enjoy internet connection without any risks of being hacked by using VPN.
Control the information that can be accessed by government any other unwanted party and surf online without being spied on. Even if you are not involved in illegal activities or trust your selection of services, platforms, be suspicious for your own security and take precautionary measures by using the VPN service.
Backup files for the later use, in case of the malware attack
Computer users can suffer from data losses due to cyber infections or their own faulty doings.
Ransomware can encrypt and hold files hostage, while unforeseen power cuts might cause a loss of important documents. If you have proper up-to-date backups, you can easily recover after such an incident and get back to work. It is also equally important to update backups on a regular basis so that the newest information remains intact - you can set this process to be performed automatically.
When you have the previous version of every important document or project you can avoid frustration and breakdowns. It comes in handy when malware strikes out of nowhere. Use for the data restoration process.
Questions about Mlsuc
Is Mlsuc a virus?
Most programs that appear the way Mlsuc did are not viruses in the strict sense. They are potentially unwanted programs:
- real software that arrives bundled with other downloads and then shows offers
- changes browser settings
- starts with Windows
Some are harmless, some are annoying and a few carry adware. What makes it worth removing is that you did not choose it.
Uninstall it from Installed apps and check the startup list and the browsers for anything added the same day. If it refuses to uninstall or returns after a restart, treat it as more serious and run a Microsoft Defender offline scan.
Mlsuc came back after I uninstalled it. Why?
Something else is reinstalling it. Common causes are a second program from the same publisher, a scheduled task that downloads it again, or a browser extension that keeps prompting for it. Sort Installed apps by install date and uninstall each entry from the same day that you did not choose.
Then open Task Scheduler and look in the Task Scheduler Library for tasks with updater-style names that you do not recognise. Check Startup apps in Task Manager too. If Mlsuc still returns, start Windows in Safe Mode, uninstall it there and run a Microsoft Defender offline scan, which looks for loaders that ordinary scans can miss.
Why can't I find Mlsuc in antivirus databases?
Because it is new or because it is listed under a different name. Antivirus companies name threats after the family they belong to, and a program that appears as Mlsuc on your PC may carry a generic or unrelated label in their databases.
Many new samples are first detected only by behaviour, without a family name. What you saw, mlsuc in the list of installed apps, is enough to act on:
- end the program
- remove its startup entry
- run a Microsoft Defender offline scan
- secure your accounts
A detection name from a scan is worth noting for later.
How dangerous is Mlsuc?
Treat it as serious until proven otherwise. The visible sign is mlsuc in the list of installed apps, 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.
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 Mlsuc, they are a strong reason to follow the full plan.
Why didn't my antivirus stop Mlsuc?
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.
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 Mlsuc 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.
Should I reset my PC because of Mlsuc?
Only if the signs point to deeper access. Reset when you see mlsuc in the list of installed apps again after removal, when Windows Security cannot start or update, when remote access tools you did not install keep appearing, or when you simply cannot trust the PC any more.
Otherwise, the plan in this guide plus an offline scan is enough. If you do reset, choose Remove everything and Cloud download for a fresh copy of Windows, restore only documents and photos, and reinstall programs from their official sites. Change important passwords from the clean system afterwards.
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 Mlsuc?
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 Mlsuc, 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
- Symantec: What is a Trojan? (read October 6, 2026)
- LesVirus: LesVirus (read October 6, 2026)
- FTC: How to recognize, remove and avoid malware (read October 6, 2026)
- Microsoft Learn: Microsoft Defender Offline (read October 6, 2026)
- Microsoft Learn: How Microsoft names malware (read October 6, 2026)