Cog Extension Virus

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Cog Extension

Cog Extension is a potentially unwanted program that places various online commercials on your screen while you surf the web. Experts in the cyber security field categorize Cog Extension as a browser hijacker and hold it responsible for aggressive ad-generation and unauthorized page redirects.

Cog Extension

The users who have Cog Extension inside their web browser (that could be Chrome, Firefox, Edge, Opera or another one) can frequently be exposed to different kinds of online promotions, pop-up messages, banner ads, offers and redirect links. On top of the ads invasion, the victims of this intrusive program can experience browser hijacking – they can have the settings of their main browsing app replaced without their approval. Cog Extension can typically take over the homepage and place a different URL that loads a specific site the very moment you open a new tab. It also can install a different search engine and impose it as the default search engine. Due to these changes, this program is considered a browser hijacker and is deemed as potentially unwanted.

The Cog Extension Chrome Virus

The Cog Extension Chrome virus uses various methods to force the affected users to access specific websites and their sponsored content. By installing supporting components like the above-mentioned search engine and by making changes to the users’ web browsing settings, the Cog Extension Chrome virus can generate an excessive amount of web advertisements on your screen and can initiate automatic redirects to specific websites.

Additional interface improvements, such as installing a new toolbar, a redirect button and other elements may also take effect without your approval. Unfortunately, if you try to uninstall any of these elements or to remove the imposed changes, you may find out that nothing works. The browser hijackers are much harder to remove than the regular apps that you have on your computer. That’s why if you want to effectively deal with Cog Extension and eliminate its components, you will definitely need some guidance either in the form of a manual removal guide (such as the one that you will find below) or a professional removal tool that can help you detect the unwanted software in a matter of minutes.

Should you be worried if you have Cog Extension in your system?

Most of the users who realize that they have a browser hijacker like Cog Extension, Mouse Extension or Ultra Extension on their system get worried about the safety of their system. In a way, such a worry is reasonable and understandable because this type of software is typically very intrusive and can make changes that can heavily affect the users’ web browsing experience. After all, there is probably no web user that won’t be worried if he notices unauthorized browser modifications and a stream of aggressively popping online commercials all over his screen. Especially in times when nasty computer infections such as Ransomware, Trojans, Spyware and other viruses lurk from every corner of the web and frequently use attractive-looking advertisements and fake links to infect unsuspecting web users.

This gives us a good reason to treat programs like Cog Extension with caution even though they don’t normally have harmful features and are not linked to criminal activities. Besides, the best way to protect your computer from a close encounter with an online danger from the rank of the above-mentioned Ransomware viruses, Trojan and other malware still remains the good old prevention which includes uninstalling any unnecessary software that can initiate potentially unwanted activities.


NameCog Extension
TypeBrowser Hijacker
Detection Tool

*Source of claim SH can remove it.

Remove Cog Extension Virus

To try and remove Cog Extension quickly you can try this:

  1. Go to your browser’s settings and select More Tools (or Add-ons, depending on your browser).
  2. Then click on the Extensions tab.
  3. Look for the Cog Extension extension (as well as any other unfamiliar ones).
  4. Remove Cog Extension by clicking on the Thrash Bin icon next to its name.
  5. Confirm and get rid of Cog Extension and any other suspicious items.

If this does not work as described please follow our more detailed Cog Extension removal guide below.

If you have a Windows virus, continue with the guide below.

If you have a Mac virus, please use our How to remove Ads on Mac guide.

If you have an Android virus, please use our Android Malware Removal guide.

If you have an iPhone virus, please use our iPhone Virus Removal guide


Some of the steps will likely require you to exit the page. Bookmark it for later reference.

Reboot in Safe Mode (use this guide if you don’t know how to do it).



*Source of claim SH can remove it.

Press CTRL + SHIFT + ESC at the same time and go to the Processes Tab (the “Details” Tab on Win 8 and 10). Try to determine which processes are dangerous.


Right click on each of them and select Open File Location. Then scan the files with our free online virus scanner:

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    After you open their folder, end the processes that are infected, then delete their folders.

    Note: If you are sure something is part of the infection – delete it, even if the scanner doesn’t flag it. No anti-virus program can detect all infections.


    Hold together the Start Key and R. Type appwiz.cpl –> OK.


    You are now in the Control Panel. Look for suspicious entries. Uninstall it/them.

    Type msconfig in the search field and hit enter. A window will pop-up:


    Startup —> Uncheck entries that have “Unknown” as Manufacturer or otherwise look suspicious.


    *Source of claim SH can remove it.

    Hold the Start Key and R copy + paste the following and click OK:

    notepad %windir%/system32/Drivers/etc/hosts

    A new file will open. If you are hacked, there will be a bunch of other IPs connected to you at the bottom. Look at the image below:

    hosts_opt (1)

    If there are suspicious IPs below “Localhost” – write to us in the comments.

    Open the start menu and search for Network Connections (On Windows 10 you just write it after clicking the Windows button), press enter.

    1. Right-click on the Network Adapter you are using —> Properties —> Internet Protocol Version 4 (ICP/IP), click Properties.
    2. The DNS line should be set to Obtain DNS server automatically. If it is not, set it yourself.
    3. Click on Advanced —> the DNS tab. Remove everything here (if there is something) —> OK.

    • After you complete this step, the threat will be gone from your browsers. Finish the next step as well or it may reappear on a system reboot.

    Right click on the browser’s shortcut —> Properties.

    NOTE: We are showing Google Chrome, but you can do this for Firefox and IE (or Edge).


    Properties —–> Shortcut. In Target, remove everything after .exe.

    Browser Hijacker Removal Instructions

    ie9-10_512x512 Remove Cog Extension from Internet Explorer:

    Open IE, click IE GEAR —–> Manage Add-ons.

    pic 3

    Find the threat —> Disable. Go to IE GEAR —–> Internet Options —> change the URL to whatever you use (if hijacked) —> Apply.

    firefox-512 Remove Cog Extension from Firefox:

    Open Firefox, click mozilla menu ——-> Add-ons —-> Extensions.

    pic 6

    Find the adware/malware —> Remove.
    chrome-logo-transparent-backgroundRemove Cog Extension from Chrome:

    Close Chrome. Navigate to:

    C:/Users/!!!!USER NAME!!!!/AppData/Local/Google/Chrome/User Data. There is a Folder called “Default” inside:

    Rename the Folder to Backup Default

    Rename it to Backup Default. Restart Chrome.


    Type Regedit in the windows search field and press Enter.

    Inside, press CTRL and F together and type the threat’s Name. Right click and delete any entries you find with a similar name. If they don’t show up this way, go manually to these directories and delete/uninstall them:

    • HKEY_CURRENT_USER—-Software—–Random Directory. It could be any one of them – ask us if you can’t discern which ones are malicious.
      HKEY_CURRENT_USER—-Software—Microsoft—-Windows—CurrentVersion—Run– Random
      HKEY_CURRENT_USER—-Software—Microsoft—Internet Explorer—-Main—- Random

    If the guide doesn’t help, download the anti-virus program we recommended or try our free online virus scanner. Also, you can always ask us in the comments for help!


    About the author


    Lidia Howler

    Lidia is a web content creator with years of experience in the cyber-security sector. She helps readers with articles on malware removal and online security. Her strive for simplicity and well-researched information provides users with easy-to-follow It-related tips and step-by-step tutorials.

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