How to remove CornusMas malicious extension
Written by Tomas Meskauskas on
What kind of program is CornusMas?
Upon testing the app, the conclusion is that CornusMas is a dubious application that activates the "Managed by your organization" setting in Chrome and Edge browsers and can read data on all pages and manage themes and extensions. It is also important to note that CornusMas is distributed using a malicious installer.
CornusMas in detail
The "Managed by your organization" setting is typically associated with organizational policies and control over browser configurations. CornusMas could exploit this setting to implement changes that serve its dubious purposes, potentially leading to a compromised and less secure online experience for users who have inadvertently added the CornusMas application.
Also, CornusMas has the capability to read data on all pages, indicating a potential privacy concern. This level of access means that the application can access and retrieve information (including sensitive data like credit card details and passwords) from any website or visited by the user, raising questions about user data security and privacy.
Furthermore, CornusMas has the ability to manage themes and extensions in browsers. This indicates a level of control over the appearance and functionality of the browser, suggesting that the app may be capable of making unauthorized changes to the user's browsing experience.
Additionally, CornusMas is distributed using a malicious installer that contains other unwanted apps, such as the Chromstera browser. Also, the distribution of CornusMas may involve browser hijackers, adware, or other unwanted programs.
| Name | CornusMas unwanted application |
| Threat Type | Malicious Extension |
| Detection Names (Installer) | Gridinsoft (PUP.Win32.Chromnius.dg!c), Kaspersky (Not-a-virus:VHO:AdWare.Win32.WebCompanion.gen), Rising (Adware.WebCompanion!8.171BF (CLOUD)), ZoneAlarm by Check Point (Not-a-virus:HEUR:AdWare.Win32.WebCompanion.gen), Full List (VirusTotal) |
| Symptoms | The "Managed by your organization" feature is activated in Chrome and Edge browser, Chromstera browser is installed, your computer becomes slower than normal, you see unwanted pop-up ads, you are redirected to dubious websites. |
| Distribution methods | Dubious websites, malicious installers, deceptive pop-up ads, free software installers (bundling), torrent file downloads. |
| Damage | Internet browser tracking (potential privacy issues), display of unwanted ads, redirects to dubious websites, loss of private information. |
| Malware Removal (Windows) | To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. |
Conclusion
In conclusion, CornusMas is a potentially harmful application with the ability to compromise user privacy and control browser settings. Users are advised to exercise caution, avoid adding the app, and take necessary steps to remove it if already added. The same applies to apps bundled with CornusMas.
Examples of extensions similar to CornusMas are PakicetusAttocki, Platyhelminthes, and SaxifragaGranulata.
How did unwanted software install on my computer?
In many cases, dubious applications are bundled with seemingly legitimate, often free, programs. Users may unknowingly install or add these applications when completing installations without deselecting unwanted offers. This typically occurs when users overlook or fail to adjust settings like "Advanced", "Custom", or similar options.
Additionally, the distribution of questionable applications extends to various channels, including peer-to-peer (P2P) networks, third-party app stores, deceptive advertisements, pop-ups, counterfeit software updates, compromised websites, and similar platforms.
In the case of CornusMas, a malicious installer hosted on a shady website is employed for distribution.
How to avoid installation of unwanted applications?
Exercise caution when downloading software and primarily utilize official and reputable sources. Avoid downloading applications from unverified websites, third-party app stores, or links provided in suspicious emails or pop-ups.
Always opt for the "Advanced" or "Custom" installation settings when adding new programs, and carefully review the installation options to deselect any bundled or unwanted software. Additionally, regularly update the operating system and security software.
If your computer is already infected with rogue applications, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate them.
Website hosting the installer used to distribute CornusMas:
CornusMas application details:
CornusMas on Edge browser:
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:
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Quick menu:
- What is CornusMas?
- STEP 1. Uninstall unwanted applications using Control Panel.
- STEP 2. Remove rogue plug-ins from Google Chrome.
- STEP 3. Remove rogue extensions from Mozilla Firefox.
- STEP 4. Remove malicious extensions from Safari.
- STEP 5. Remove rogue plug-ins from Microsoft Edge.
Unwanted software removal:
Windows 11 users:
Right-click on the Start icon, select Apps and Features. In the opened window search for the application you want to uninstall, after locating it, click on the three vertical dots and select Uninstall.
Windows 10 users:
Right-click in the lower left corner of the screen, in the Quick Access Menu select Control Panel. In the opened window choose Programs and Features.
Windows 7 users:
Click Start (Windows Logo at the bottom left corner of your desktop), choose Control Panel. Locate Programs and click Uninstall a program.
macOS (OSX) users:
Click Finder, in the opened screen select Applications. Drag the app from the Applications folder to the Trash (located in your Dock), then right click the Trash icon and select Empty Trash.
In the uninstall programs window, look for any unwanted applications, select these entries and click "Uninstall" or "Remove".
After uninstalling the unwanted application, scan your computer for any remaining unwanted components or possible malware infections. To scan your computer, use recommended malware removal software.
Remove unwanted apps from Internet browsers:
Video showing how to remove unwanted browser add-ons:
Remove malicious extensions from Google Chrome:
Click the Chrome menu icon 
(at the top right corner of Google Chrome), select "Extensions" and click "Manage Extensions". Locate "CornusMas" or other suspicious extensions, select these entries and click "Remove".
Optional method:
If you continue to have problems with removal of the cornusmas unwanted application, reset your Google Chrome browser settings. Click the Chrome menu icon (at the top right corner of Google Chrome) and select Settings. Scroll down to the bottom of the screen. Click the Advanced… link.
After scrolling to the bottom of the screen, click the Reset (Restore settings to their original defaults) button.
In the opened window, confirm that you wish to reset Google Chrome settings to default by clicking the Reset button.
Remove malicious plug-ins from Mozilla Firefox:
Click the Firefox menu 
(at the top right corner of the main window), select "Add-ons and themes". Click "Extensions", in the opened window locate all recently-installed suspicious extensions, click on the three dots and then click "Remove".
Optional method:
Computer users who have problems with cornusmas unwanted application removal can reset their Mozilla Firefox settings.
Open Mozilla Firefox, at the top right corner of the main window, click the Firefox menu, in the opened menu, click Help.
Select Troubleshooting Information.
In the opened window, click the Refresh Firefox button.
In the opened window, confirm that you wish to reset Mozilla Firefox settings to default by clicking the Refresh Firefox button.
Remove malicious extensions from Safari:
Make sure your Safari browser is active, click Safari menu, and select Preferences....
In the opened window click Extensions, locate any recently installed suspicious extension, select it and click Uninstall.
Optional method:
Make sure your Safari browser is active and click on Safari menu. From the drop down menu select Clear History and Website Data...
In the opened window select all history and click the Clear History button.
Remove malicious extensions from Microsoft Edge:
Click the Edge menu icon 
(at the upper-right corner of Microsoft Edge), select "Extensions". Locate all recently-installed suspicious browser add-ons and click "Remove" below their names.
Optional method:
If you continue to have problems with removal of the cornusmas unwanted application, reset your Microsoft Edge browser settings. Click the Edge menu icon (at the top right corner of Microsoft Edge) and select Settings.
In the opened settings menu select Reset settings.
Select Restore settings to their default values. In the opened window, confirm that you wish to reset Microsoft Edge settings to default by clicking the Reset button.
- If this did not help, follow these alternative instructions explaining how to reset the Microsoft Edge browser.
Summary:
Commonly, adware or potentially unwanted applications infiltrate Internet browsers through free software downloads. Note that the safest source for downloading free software is via developers' websites only. To avoid installation of adware, be very attentive when downloading and installing free software. When installing previously-downloaded free programs, choose the custom or advanced installation options – this step will reveal any potentially unwanted applications listed for installation together with your chosen free program.
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Frequently Asked Questions (FAQ)
What harm can CornusMas cause?
CornusMas can cause significant harm by compromising user privacy through unauthorized data access and manipulating browser settings, themes, and extensions, potentially leading to security vulnerabilities.
What does CornusMas do?
CornusMas is a potentially malicious application that, upon activation, utilizes the "Managed by your organization" setting in Chrome and Edge browsers. Also, it can read data on all pages and manage themes and extensions.
How do CornusMas developers generate revenue?
The developers of CornusMas may generate revenue through illicit means, such as data harvesting, selling user information, engaging in click fraud, or participating in other fraudulent activities.
Will Combo Cleaner remove CornusMas?
Combo Cleaner will remove unwanted applications from your computer. Remember that manual removal might not be effective, as some file remnants could persist in the system even after deleting the software, potentially remaining active.
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