Dllhost.exe COM Surrogate – How to Spot and Remove Malware

Dllhost.exe COM Surrogate is a key Windows process that manages Component Object Model (COM) objects. Malware often disguises itself as dllhost.exe COM Surrogate to hide its activities. This guide examines dllhost.exe COM Surrogate in depth.

Windows Task Manager

What is Dllhost.exe COM Surrogate?

Dllhost.exe COM Surrogate is a process that hosts COM server objects, allowing them to run in isolated surrogate processes for stability and security. Its responsibilities include:

  • Loading COM objects into surrogated host processes
  • Managing the lifecycle of COM-based components
  • Providing COM services like security, threading, and transactions
  • Enabling inter-process COM communications
  • Implementing COM process isolation and integrity levels

By hosting COM objects separately, dllhost.exe COM Surrogate prevents faulty components from crashing applications and contains threats.

File Details

Here are some quick facts on dllhost.exe COM Surrogate:

  • Location: C:\Windows\System32
  • Default name: dllhost.exe
  • Digitally signed by: Microsoft Corporation

Dllhost.exe COM Surrogate runs from System32 and has Microsoft’s digital signature.

Normal Dllhost.exe COM Surrogate Behavior

When operating properly, dllhost.exe COM Surrogate exhibits this behavior:

  • Multiple instances – Many dllhost.exe processes run, each hosting different COM objects.
  • Changing processes – Dllhost.exe processes start and stop dynamically based on COM object usage.
  • Child COM processes – Legitimate dllhost instances spawn COM DLL-based processes only.
  • Typical resource usage – Utilizes minimal memory and CPU itself, increased only by hosted COM activity.
  • No direct internet access – Dllhost.exe does not make outbound connections itself.

If dllhost.exe aligns with these parameters, it is legitimate and trusted.

How Malware Abuses Dllhost.exe COM Surrogate

Cybercriminals leverage dllhost.exe COM Surrogate to covertly infect systems using techniques like:

  1. Name spoofing – Malware calls itself dllhost.exe to appear as a legitimate process.
  2. COM hijacking – Malware registers itself as a COM object so dllhost.exe loads it into memory.
  3. Elevation – Gaining dllhost.exe’s heightened privileges to bypass security controls.
  4. Persistence – Malware adds itself to the registry to persistently restart as dllhost.exe.
  5. Stealth – Blending in as dllhost.exe allows malware to disguise its activities.

Once embedded into dllhost.exe, malware can:

  • Steal sensitive data and credentials
  • Access protected system resources
  • Download payloads and additional threats
  • Establish backdoors for remote access
  • Disable security software
  • Spread infections across networks

How to Spot Malicious Dllhost.exe COM Surrogate

While devious, counterfeit dllhost.exe exhibits these telltale signs:

  1. Verify location – Legitimate dllhost runs only from System32. Other locations point to an imposter.
  2. Check process metadata – Properties like command lines and parent processes should align to COM. Anomalies are suspicious.
  3. Confirm digital signature – Authentic dllhost.exe contains Microsoft’s digital signature. Malware often lacks a valid signature.
  4. Review active COM objects – Cross check running COM objects against dllhost processes. Mismatching items indicate a fake.
  5. Examine child processes – Malware dllhost may spawn non-COM executables and other suspicious programs.
  6. Monitor resource usage – Malicious dllhost tends to consume more memory, CPU and disk usage than legitimate processes.
  7. Inspect network traffic – Real dllhost does not make direct internet connections. Outbound traffic indicates malware.
  8. Run an antivirus scan – Antivirus can detect known dllhost malware variants through signature matching.

Spotting these red flags helps identify malicious dllhost.exe threats impersonating COM Surrogate.

Removing Malicious Dllhost.exe COM Surrogate

This malware removal guide may appear overwhelming due to the number of steps and numerous programs that are being used. We have only written it this way to provide clear, detailed, and easy-to-understand instructions that anyone can use to remove malware for free.
Please perform all the steps in the correct order. If you have any questions or doubts at any point, stop and ask for our assistance.
To remove the Dllhost.exe COM Surrogate Trojan and other malware from your computer, follow these steps:

STEP 1: Use Rkill to terminate malicious processes

In this first step, we will download and run Rkill to terminate malicious processes that may be running on your computer.

RKill is a program that was developed at BleepingComputer.com that attempts to terminate known malware processes so that your normal security software can then run and clean your computer of infections. When RKill runs it will kill malware processes and then removes incorrect executable associations and fixes policies that stop us from using certain tools.

  1. Download Rkill.

    You can download RKill to your computer from the below link. When at the download page, click on the Download Now button labeled iExplore.exe. We are downloading a renamed version of Rkill (iExplore.exe) because some malware will not allow processes to run unless they have a certain filename.

    RKILL DOWNLOAD LINK

    (The above link will open a new page from where you can download Rkill)
  2. Run RKill.

    After downloading, double-click the iExplore.exe icon to kill malicious processes. In most cases, downloaded files are saved to the Downloads folder.
    The program may take some time to search for and end various malware programs.

    RKILL Window

    When it is finished, the black window will close automatically and a log file will open. Do not restart your computer. Proceed to the next step in this guide.

STEP 2: Uninstall malicious programs from Windows

In this second step, we will manually check if any unknown or malicious programs are installed on the computer. Sometimes adware and browser hijackers can have a usable Uninstall entry that can be used to remove them.

Windows 11Windows 10Windows 8Windows 7
  1. Press the Windows key + I on your keyboard to open the Settings app.

    First, open Windows Settings by pressing Windows+I on your keyboard. You can also right-click your Start button and select “Settings” from the list.
    Windows 11 Open Settings

  2. In the Settings app, click on “Apps” and then “Apps & features”.

    When Settings opens, click “Apps” in the sidebar, then select “Apps & Features”.

    Windows 11 Apps and Feature

  3. Find the malicious program in the list of installed apps and uninstall it.

    In Apps & Features settings, scroll down to the app list and search for unknown or suspicious programs. To make things easier, you can sort all installed programs by their installation date. To do this, click “Sort by” and select “Install date”.
    Look out for any suspicious program that could be behind all the drama – anything you don’t remember downloading or that doesn’t sound like a genuine program. When you find a malicious program, click the three dots button beside it and select “Uninstall” in the menu that appears.

    Windows 11 Uninstall malicious program

    If you have checked your computer for malicious programs and did not find any, you can proceed with the next step in this guide.
  4. Follow the prompts to uninstall the program.

    In the next message box, confirm the uninstall process by clicking on Uninstall, then follow the prompts to uninstall the malicious program.
    Make sure to read all of the prompts carefully, because some malicious programs try to sneak things in hoping that you won’t read them closely.

    Windows 11 Confirm Uninstall

  1. Press the Windows key + I on your keyboard to open the Settings app.

    Press the Windows key + I on your keyboard to open the Settings app. You can also ope the Settings app by clicking the Start button on the taskbar, then select “Settings” (gear icon).
    Windows 10: Click the Start button then click on Settings

  2. In the Settings app, click on “Apps”.

    When the “Windows Settings” window opens, click on “Apps“. By default, it should open “Apps and Features” but if it doesn’t, select it from the list on the left.

    Windows 10: Click on Apps

  3. Find the malicious program in the list of installed apps and uninstall it.

    In Apps & Features settings, scroll down to the app list and search for unknown or suspicious programs. To make things easier, you can sort all installed programs by their installation date. To do this, click “Sort by” and select “Install date”.
    Look out for any suspicious program that could be behind all the drama – anything you don’t remember downloading or that doesn’t sound like a genuine program. When you find a malicious program, click on it and select “Uninstall” in the menu that appears.

    Windows 10: Uninstall malware from Windows

    If you have checked your computer for malicious programs and did not find any, you can proceed with the next step in this guide.
  4. Follow the prompts to uninstall the program.

    In the next message box, confirm the uninstall process by clicking on Uninstall, then follow the prompts to uninstall the malicious program.
    Make sure to read all of the prompts carefully, because some malicious programs try to sneak things in hoping that you won’t read closely.
    Windows 10: Complete the uninstall process

  1. Go to “Program and Features”.

    Right-click on the Start button in the taskbar, then select “Programs and Features”. This will take you directly to your list of installed programs.
    Right click on Start and select Programs and Features

  2. Search for malicious program and uninstall it.

    The “Programs and Features” screen will be displayed with a list of all the programs installed on your computer. Scroll through the list until you find any unknown or suspicious program, then click to highlight it, then click the “Uninstall” button.

    Look out for any suspicious program that could be behind all the drama – anything you don’t remember downloading or that doesn’t sound like a genuine program.

    If you have checked your computer for malicious programs and did not find any, you can proceed with the next step in this guide.

    Select malicious program then click on Uninstall

  3. Follow the on-screen prompts to uninstall malicious program.

    In the next message box, confirm the uninstall process by clicking on Yes, then follow the prompts to uninstall malicious program. Make sure to read all of the prompts carefully, because some malicious programs try to sneak things in hoping that you won’t read closely.

  1. Open the “Control Panel”.

    Click on the “Start” button, then click on “Control Panel“.
    Windows 7 go to Control Panel

  2. Click on “Uninstall a Program”.

    When the “Control Panel” appears, click on “Uninstall a Program” from the Programs category.
    Select Uninstall malicious program from Control Panel

  3. Search for malicious programs and uninstall them.

    The “Programs and Features” screen will be displayed with a list of all the programs installed on your computer. Scroll through the list until you find any suspicious or unknown program, then click to highlight it, then click the “Uninstall” button.
    Look out for any suspicious program that could be behind all the drama – anything you don’t remember downloading or that doesn’t sound like a genuine program.

    If you have checked your computer for malicious programs and did not find any, you can proceed with the next step in this guide.

    Uninstall malware from Windows 7

  4. Follow the on-screen prompts to uninstall malicious program.

    In the next message box, confirm the uninstall process by clicking on Yes, then follow the prompts to uninstall malicious program. Make sure to read all of the prompts carefully, because some malicious programs try to sneak things in hoping that you won’t read closely.

If you are experiencing difficulty while attempting to uninstall a program, you can use Revo Uninstaller to completely remove the unwanted program from your computer.

Now that the malicious programs have been removed from your computer, we can proceed with the next step in this guide.

STEP 3: Reset browsers back to default settings

In this step, we will remove spam notifications,  malicious extensions, and change to default any settings that might have been changed by malware.
Please note that this method will remove all extensions, toolbars, and other customizations but will leave your bookmarks and favorites intact. For each browser that you have installed on your computer, please click on the browsers tab below and follow the displayed steps to reset that browser.

ChromeFirefoxMicrosoft EdgeInternet Explorer
Reset Chrome for Windows to default settings

We will now reset your Chrome browser settings to their original defaults. This will reset your startup page, new tab page, search engine, and pinned tabs. It will also disable all extensions and clear temporary data like cookies. Your favorites, history, and saved passwords will not be cleared.

  1. Click the three dots in the top-right corner and then click on “Settings”.

    Open Chrome and click on the menu button (represented by three vertical dots) in the top right corner of the window. In the dropdown menu that opens, click “Settings“. Click on the Chrome menu button then on the Settings button
  2. Click “Advanced”.

    Chrome’s “Settings” should now be displayed in a new tab or window, depending on your configuration. In the left sidebar, click on the “Advanced” link. Click on the Advanced link
  3. Click “Reset and clean up”.

    In the left sidebar, under the “Advanced” section, click on “Reset and clean up“. Click Reset and clean up button
  4. Click “Reset settings to their original defaults”.

    In the main window, the “Reset and clean up” section is visible, as shown in the screenshot below. Click on “Reset settings to their original defaults“. Click on Reset settings to their original defaults
  5. Click “Reset settings”.

    A confirmation dialog will now be displayed, detailing the components that will be restored to their default state should you continue with the reset process. To complete the restoration process, click on the “Reset settings” button. Click on Reset Settings to restore Google Chrome to its default settings
  6. (Optional) Reset Chrome Data Sync.

    In case a malicious extension reinstalls itself even after performing a browser reset, you have an additional option to reset the data sync for your browser. To do this, navigate to chrome.google.com/sync and click on the Clear Data button. Chrome Sync Reset
Reset Firefox for Windows to default settings

We will now reset your Firefox browser settings to their default. The reset feature fixes many issues by restoring Firefox to its factory default state while saving your essential information like bookmarks, passwords, web form auto-fill information, browsing history, and open tabs.

  1. Click the three horizontal lines in the top-right corner and then click on “Help”.

    Click on Firefox’s main menu button, represented by three horizontal lines. When the drop-down menu appears, select the option labeled “Help“.
    Click on the Firefox Menu button then select Help button

  2. Click “More troubleshooting information”.

    From the Help menu, click on “More troubleshooting information“.
    Click More Troubleshooting Information

  3. Click on “Refresh Firefox”

    When the “Troubleshooting Information” page opens, click on the “Refresh Firefox” button.
    Click on Refresh Firefox

  4. Confirm that you want to reset your browser settings.

    To finish the reset process, click on the “Refresh Firefox” button in the new confirmation window that opens.
    Click again on Refresh Firefox button

  5. Click “Finish”.

    Firefox will now close itself and will revert to its default settings. When it’s done, a window will list the information that was imported. Click on “Finish“.

    Your old Firefox profile will be placed on your desktop in a folder named “Old Firefox Data“. If the reset didn’t fix your problem you can restore some of the information not saved by copying files to the new profile that was created. If you don’t need this folder any longer, you should delete it as it contains sensitive information.

Reset Microsoft Edge to default settings

We will now reset your Microsoft Edge browser settings to their default. This will reset your startup page, new tab page, search engine, and pinned tabs. It will also disable all extensions and clear temporary data like cookies. Your favorites, history, and saved passwords will not be cleared.

  1. Click the three dots in the top-right corner and then click on “Settings”.

    In the top right corner, click on Microsoft Edge’s main menu button, represented by three horizontal dots. When the drop-down menu appears, click on “Settings“.
    Click the three dots in the top-right corner and then click on Settings

  2. Click on “Reset Settings”.

    On the left side of the window, click on “Reset Settings“.
    Click Reset Settings option

  3. Click on “Restore settings to their default values”.

    In the main window, click on “Restore settings to their default values“.
    Select Restore settings to their default values

  4. Click “Reset”.

    A confirmation dialog should now be displayed, detailing the components that will be restored to their default state should you continue with the reset process. To complete the restoration process, click on the “Reset” button.
    Click Reset to reset your browser
    Microsoft Edge will now erase all your personal data, browsing history, and disable all installed extensions. Your bookmarks, though, will remain intact and still be accessible.

Reset Internet Explorer to default settings

We will now reset your Internet Explorer browser settings to their default. You can reset Internet Explorer settings to return them to the state they were in when Internet Explorer was first installed on your computer.

  1. Go to “Internet Options”.

    Open Internet Explorer, click on the gear icon in the upper-right part of your browser, then select “Internet Options“.

  2. Select the “Advanced” tab, then click “Reset”

    In the “Internet Options” dialog box, select the “Advanced” tab, then click on the “Reset” button.

  3. Click on “Reset”.

    In the “Reset Internet Explorer settings” section, select the “Delete personal settings” checkbox, then click on the “Reset” button.

  4. Click on “Close”.

    When Internet Explorer has completed its task, click on the “Close” button in the confirmation dialogue box.
    Close your browser and then you can open Internet Explorer again.

STEP 4: Use Malwarebytes to remove for Trojans and Unwanted Programs

In this next step, we will we will install Malwarebytes to scan and remove any infections, adware, or potentially unwanted programs that may be present on your computer.

Malwarebytes is one of the most popular and most used anti-malware software for Windows, and for good reasons. It is able to destroy many types of malware that other software tends to miss, without costing you absolutely nothing. When it comes to cleaning up an infected device, Malwarebytes has always been free and we recommend it as an essential tool in the fight against malware.

  1. Download Malwarebytes for Windows.

    You can download Malwarebytes by clicking the link below.

    MALWAREBYTES FOR WINDOWS DOWNLOAD LINK
    (The above link will open a new page from where you can download Malwarebytes)
  2. Double-click on the Malwarebytes setup file.

    When Malwarebytes has finished downloading, double-click on the MBSetup file to install Malwarebytes on your computer. In most cases, downloaded files are saved to the Downloads folder.

    Download

    You may be presented with a User Account Control pop-up asking if you want to allow Malwarebytes to make changes to your device. If this happens, you should click “Yes” to continue with the Malwarebytes installation.

    Click Yes to install Malwarebytes

  3. Follow the on-screen prompts to install Malwarebytes.

    When the Malwarebytes installation begins, you will see the Malwarebytes setup wizard which will guide you through the installation process. The Malwarebytes installer will first ask you what type of computer are you installing this program on, click either Personal Computer or Work Computer.
    Malwarebytes setup: Click on Personal Computer

    On the next screen, click “Install” to install Malwarebytes on your computer.

    Click on Install to install Malwarebytes

    When your Malwarebytes installation completes, the program opens the Welcome to Malwarebytes screen.

  4. Click on “Scan”.

    Malwarebytes is now installed on your computer, to start a scan click on the “Scan” button. Malwarebytes will automatically update the antivirus database and start scanning your computer for malicious programs.

    Click on Scan button

  5. Wait for the Malwarebytes scan to complete.

    Malwarebytes will now scan your computer for browser hijackers and other malicious programs. This process can take a few minutes, so we suggest you do something else and periodically check on the status of the scan to see when it is finished.

    Malwarebytes scanning for malware

  6. Click on “Quarantine”.

    When the Malwarebytes scan is finished scanning it will show a screen that displays any malware, adware, or potentially unwanted programs that it has detected. To remove the adware and other malicious programs that Malwarebytes has found, click on the “Quarantine” button.

    Review the malicious programs and click on Quarantine to remove malware

  7. Restart computer.

    Malwarebytes will now remove all the malicious files and registry keys that it has found. To complete the malware removal process, Malwarebytes may ask you to restart your computer.
    Malwarebytes requesting to restart computer to complete the malware removal process

STEP 5: Use HitmanPro to remove Rootkits and other Malware

In this fifth step, while the computer is in normal back, we will download and run a scan with HitmanPro to remove Trojans, rootkits, and other malicious programs.

HitmanPro is a second-opinion scanner that takes a unique cloud-based approach to malware scanning. HitmanPro scans the behavior of active files and also files in locations where malware normally resides for suspicious activity. If it finds a suspicious file that’s not already known, HitmanPro sends it to its clouds to be scanned by two of the best antivirus engines today, which are Bitdefender and Kaspersky.

Although HitmanPro is shareware and costs $24.95 for 1 year on 1 PC, there is no limit on scanning. The limitation only kicks in when there is a need to remove or quarantine detected malware by HitmanPro on your system and by then, you can activate the one-time 30-days trial to enable the cleanup.

  1. Download HitmanPro.

    You can download HitmanPro by clicking the link below.

    HITMANPRO DOWNLOAD LINK
    (The above link will open a new web page from where you can download HitmanPro)
  2. Install HitmanPro.

    When HitmanPro has finished downloading, double-click on “hitmanpro.exe” (for 32-bit versions of Windows) or “hitmanpro_x64.exe” (for 64-bit versions of Windows) to install this program on your computer. In most cases, downloaded files are saved to the Downloads folder.

    Double-click on the HitmanPro file

    You may be presented with a User Account Control pop-up asking if you want to allow HitmanPro to make changes to your device. If this happens, you should click “Yes” to continue with the installation.

    Windows asking for permissions to run the HitmanPro setup

  3. Follow the on-screen prompts.

    When HitmanPro starts you will be presented with the start screen as shown below. Click on the “Next” button to perform a system scan.

    Click Next to install HitmanPro on your PC

    HitmanPro final installer screen

  4. Wait for the HitmanPro scan to complete.

    HitmanPro will now begin to scan your computer for malicious programs.
    HitmanPro scans your computer for any infections, adware, or potentially unwanted programs that may be present

  5. Click on “Next”.

    When HitmanPro has finished the scan, it will display a list of all the malware that it has found. Click on the “Next” button to have HitmanPro remove the detected items.

    HitmanPro scan summary. Click Next to remove malware

  6. Click on “Activate free license”.

    HitmanPro may now require to activate the free 30-days trial to remove the malicious files. To do this, click on the “Activate free license” button to begin the free 30 days trial and remove all the malicious files from your computer.
    Click on the Activate free license button

    When the malware removal process is complete, it will display a screen that shows the status of the various programs that were removed. At this screen, you should click on the Next button and then if prompted you should click on the Reboot button. If HitmanPro does not prompt you to reboot, please just click on the Close button.

STEP 6: Use AdwCleaner to remove Malicious Browser Policies and Adware

In this next step, we will use AdwCleaner to remove malicious browser policies and unwanted browser extensions from your computer.

AdwCleaner is a free popular on-demand scanner that can detect and remove malware that even the most well-known anti-virus and anti-malware applications fail to find. This on-demand scanner includes a lot of tools that can be used to fix the side effects of adware. browser hijackers and other malware.

  1. Download AdwCleaner.

    You can download AdwCleaner by clicking the link below.

    ADWCLEANER DOWNLOAD LINK

    (The above link will open a new web page from where you can download AdwCleaner)
  2. Double-click on the setup file.

    Double-click on the file named “adwcleaner_x.x.x.exe” to start AdwCleaner. In most cases, downloaded files are saved to the Downloads folder.
    Download AdwCleaner on your computer

    AdwCleaner program will now open and you will be presented with the program’s license agreement. After you read it, click on the I agree button if you wish to continue. If Windows prompts you as to whether or not you wish to run AdwCleaner, please allow it to run.

    Windows ask if you want to run AdwCleaner

  3. Enable “Reset Chrome policies” to remove malicious browser policies.

    When AdwCleaner starts, on the left side of the window, click on “Settings” and then enable “Reset Chrome policies“.

    Enable Reset Chrome policies to remove malicious browser policies

  4. Click on the “Scan” button.

    On the left side of the AdwCleaner window, click on “Dashboard” and then click “Scan” to perform a computer scan.

    Click on Scan to start a AdwCleaner scan

  5. Wait for the AdwCleaner scan to finish.

    AdwCleaner will now scan your computer for malware. This process can take a few minutes.

    AdwCleaner scanning for adware and other malware

  6. Click on “Quarantine” to remove malware.

    When the AdwCleaner scan is completed it will display all of the items it has found. Click on the “Quarantine” button to remove the malicious programs from your computer.

    Click on Quarantine to remove malware

  7. Click on “Continue” to remove the malicious programs.

    AdwCleaner will now prompt you to save any open files or data as the program will need to close any open programs before it starts to clean. Click on the “Continue” button to finish the removal process.
    Click Continue to remove malicious files

    AdwCleaner will now delete all detected malware from your computer. When the malware removal process is complete, you may be asked to restart your computer.

STEP 7: Perform a final check with ESET Online Scanner

This step involves installing and running a scan with ESET Online Scanner to check for any additional malicious programs that may be installed on the computer..

ESET Online Scanner is a free second-opinion scanner, designed to rescue your computer from malware (viruses, trojans, rootkits, etc.) that have infected your computer despite all the security measures you have taken (such as anti-virus software, firewalls, etc.).

  1. Download ESET Online Scanner.

    You can download ESET Online Scanner by clicking the link below.

    ESET ONLINE SCANNER DOWNLOAD LINK

    (The above link will open a new web page from where you can download ESET Online Scanner)
  2. Double-click on esetonlinescanner.exe to run the installer.

    When ESET Online Scanner has finished downloading, double-click on “esetonlinescanner.exe” to install it program on your computer. In most cases, downloaded files are saved to the Downloads folder.
    Image - Double-click on the ESET Online Scanner setup file

  3. Install ESET Online Scanner.

    When ESET Online Scanner starts you will be presented with the start screen as shown below. Select your desired language from the drop-down menu and click Get started.

    Image - Click Get Started to install ESET Online Scanner

    In the Terms of use screen, click Accept.
    Image - Accept Terms to Install ESET Online Scanner

    Select your preference for the Customer Experience Improvement Program and the Detection feedback system and click Continue.
    Image - Follow the on-screen prompts

  4. Start a Full Scan with ESET Online Scanner

    Click on Full Scan to perform an in-depth inspection of the entire computer.

    Start a Full Scan with ESET Online Scanner

    Select Enable for Detection of Potentially Unwanted Applications, then click Start scan.

    Image - Enable PUA Detection and Start Scan

  5. Wait for the ESET Online Scanner scan to finish.

    ESET Online Scanner will now begin to scan your computer for malware. This process can take quite a while, so we suggest you do something else and periodically check on the status of the scan to see when it is finished.

    Image- Wait for the ESET Online Scanner scan to finish

  6. ESET Online Scanner will automatically remove the malicious files.

    At the end of the scan, the Found and resolved detections screen will be displayed. You can click View detailed results to view specific information. Detected threats are automatically cleaned and quarantined.
    Image - ESET Online Scanner malware removal

STEP 8: Run the System File Checker (SFC) tool

In this step, we will use System File Checker (SFC) tool to detect and repair files that may have been corrupted by malware.

The SFC tool scans all protected system files on your computer and replaces any files that are corrupt or damaged with a cached copy that is stored in a compressed folder at %WinDir%\System32\dllcache. By running the SFC tool, you can help ensure that your system is functioning properly and fix any issues.

  1. Open Command Prompt as Administrator.

    To open the Command Prompt as an administrator in Windows, type “cmd” in the search bar and then right-click on the Command Prompt result and select “Run as administrator” as shown in the image below.
    Run CMD As Administrator
    A User Account Control (UAC) prompt will appear asking for permission to allow the program to run. Click “Yes”.

  2. Type “sfc /scannow”.

    You will now be presented with a black screen called the ‘Administrator: Command Prompt’. On this screen, type “sfc /scannow” to scan for and repair any corrupt system files.
    sfc /scannow

  3. Restart your computer.

    Restart your computer if sfc /scannow repaired files. System File Checker may or may not prompt you to restart but even if it doesn’t, you should restart anyway.

  4. Run again sfc /scannow.

    Run again sfc /scannow to check if the files were repaired.

STEP 9: Run the Disk Check tool

As a final step, we will utilize the Disk Check tool, commonly referred to as “chkdsk,” to identify and resolve any issues that were caused by malware.

This tool checks your hard disk for errors and can fix any issues it finds. To use the Disk Check tool, you will need to open the command prompt and enter the “chkdsk” command followed by the drive letter (e.g., “chkdsk C:”). You can also add the “/f” flag to the command to instruct the tool to fix any errors it finds. By running the Disk Check tool, you can help ensure that your hard disk is functioning properly and fix any issues that may be causing high disk usage.”
  1. Open Command Prompt as Administrator.

    To open the Command Prompt as an administrator in Windows, type “cmd” in the search bar and then right-click on the Command Prompt result and select “Run as administrator” as shown in the image below. Run CMD As Administrator A User Account Control (UAC) prompt will appear asking for permission to allow the program to run. Click “Yes”.
  2. Type “chkdsk /f /r”

    You will now be presented with a black screen called the ‘Administrator: Command Prompt’. On this screen, type “chkdsk /f /r” to repair any errors on your hard drive. chkdsk /f /r
  3. Restart your computer

    The Disk Check tool may require you to restart your computer in order to complete the scan and repair process. Type “Y” and click on Enter, then restart the computer. A CHKDSK command can take a long time, especially when performed on larger drives. Once it’s done, however, it will present a summary of results including total disk space, byte allocation, and, most importantly, any errors that were found and corrected. CMD chkdsk f r restart

Your computer should now be free of the Dllhost.exe COM Surrogate Trojan and other malware.

If your current antivirus allowed this malicious program on your computer, you may want to consider purchasing Malwarebytes Premium to protect against these types of threats in the future.
If you are still having problems with your computer after completing these instructions, then please follow one of the steps:

The Bottom Line

Dllhost.exe COM Surrogate provides vital isolation and security for COM processes. However malware abuse remains an ongoing nuisance. Staying vigilant to warning signs and using removal best practices allows you to confidently detect and eliminate fraudulent dllhost.exe threats.

Keep your eyes peeled for shady dllhost.exe activity and apply sound security hygiene to ensure this essential Windows process works safely for you, not against you.

How to Stay Safe Online

Here are 10 basic security tips to help you avoid malware and protect your device:

  1. Use a good antivirus and keep it up-to-date.

    Shield Guide

    It's essential to use a good quality antivirus and keep it up-to-date to stay ahead of the latest cyber threats. We are huge fans of Malwarebytes Premium and use it on all of our devices, including Windows and Mac computers as well as our mobile devices. Malwarebytes sits beside your traditional antivirus, filling in any gaps in its defenses, and providing extra protection against sneakier security threats.

  2. Keep software and operating systems up-to-date.

    updates-guide

    Keep your operating system and apps up to date. Whenever an update is released for your device, download and install it right away. These updates often include security fixes, vulnerability patches, and other necessary maintenance.

  3. Be careful when installing programs and apps.

    install guide

    Pay close attention to installation screens and license agreements when installing software. Custom or advanced installation options will often disclose any third-party software that is also being installed. Take great care in every stage of the process and make sure you know what it is you're agreeing to before you click "Next."

  4. Install an ad blocker.

    Ad Blocker

    Use a browser-based content blocker, like AdGuard. Content blockers help stop malicious ads, Trojans, phishing, and other undesirable content that an antivirus product alone may not stop.

  5. Be careful what you download.

    Trojan Horse

    A top goal of cybercriminals is to trick you into downloading malware—programs or apps that carry malware or try to steal information. This malware can be disguised as an app: anything from a popular game to something that checks traffic or the weather.

  6. Be alert for people trying to trick you.

    warning sign

    Whether it's your email, phone, messenger, or other applications, always be alert and on guard for someone trying to trick you into clicking on links or replying to messages. Remember that it's easy to spoof phone numbers, so a familiar name or number doesn't make messages more trustworthy.

  7. Back up your data.

    backup sign

    Back up your data frequently and check that your backup data can be restored. You can do this manually on an external HDD/USB stick, or automatically using backup software. This is also the best way to counter ransomware. Never connect the backup drive to a computer if you suspect that the computer is infected with malware.

  8. Choose strong passwords.

    lock sign

    Use strong and unique passwords for each of your accounts. Avoid using personal information or easily guessable words in your passwords. Enable two-factor authentication (2FA) on your accounts whenever possible.

  9. Be careful where you click.

    cursor sign

    Be cautious when clicking on links or downloading attachments from unknown sources. These could potentially contain malware or phishing scams.

  10. Don't use pirated software.

    Shady Guide

    Avoid using Peer-to-Peer (P2P) file-sharing programs, keygens, cracks, and other pirated software that can often compromise your data, privacy, or both.

To avoid potential dangers on the internet, it's important to follow these 10 basic safety rules. By doing so, you can protect yourself from many of the unpleasant surprises that can arise when using the web.

26 thoughts on “Dllhost.exe COM Surrogate – How to Spot and Remove Malware”

  1. There are so e thieves stealing money and things , one is carlos sotelo pascual peruvian and the other is daniel, i am a musician , my name is paulo and the artist name is Hoju, please be aware of people calling you or contacting you with voice changer programs or fake acounts .thank you and i will be using this software and support as soon as i can, keep up the good work…..am kile

  2. My daughter had been dealing with the COM Surrogate problem for several months. The ESET solution worked like a champ. Thank you so very much for saving her and I from this headache.

  3. You can’t imagine how much pain and headache you have saved me. Like the below user said, i was really helpless before i got to this website, and i could finally rid my computer of this beast that has messed with not just my work, but my time as well in trying to figure out what was wrong, and had created a huge nightmare for me over the past few weeks. Really really thankyou very much for all of this.

  4. I would like here to thank you for the save from the very annoying , med-risked and disgusting adware “Candy-box.Biz”. I really couldn’t do anything before I arrived at your forum and executed all what you recommended and the result for the moment was a clean computer. Thanks alot, I really appreciate you and wish you a great success and accomplishement as you substantiate the meaning of humanity in the depths of your kind self.

  5. Stelian, I notice in your guide posted here that you replaced programs from a few weeks ago. For instance, I notice Step 1 a few weeks ago referred to ComboFix and now you are recommending ESET Powerlinks Cleaner. You also removed Rogue Killer which was Step 2 a few weeks ago. Any particular reason why? If I used the older 6-step process will I expect problems? Thanks.

  6. This worked like a charm. Following it (pretty much) word-for-word, it did what it said it would do. Thanks, Stelian, for providing a simple, straight-forward document as a resolve for such removals. Awesome.

  7. This is an update from a comment I left 5 days ago. I went through the steps with some trepidation and it took me all day because I ran into trouble not being able to download. I figured that out and then lost my file that enables you to connect to the Wi-Fi which of course I lost internet connection. I figured that out by rebooting two times; could not get Emsisoft emergency kit to run, had to use the search and find files on my start menu to find the download and open it there to run it. Been using the computer for a few hours now and I haven’t encountered any problems. I will update this comment in a few days after I had time to use the computer more. Thanks Stelian for this information, well done..

  8. This is a great guide! It was very easy to follow and well explained. Thank you so much for your help!

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