Crypto-Loot Virus
Written by Tomas Meskauskas on (updated)
What is Crypto-Loot?
Similar to Coinhive, Crypto-Loot is a service that allows web developers to inject their sites with a script that employs visitors' computers to mine Monero cryptocurrency.
The service itself is legitimate, however, some developers become greedy and abuse the Crypto-Loot service. They start mining without users' consent and do not limit the use of system resources - they use up to 100% of computer resources without permission.
Crypto-Loot is essentially JavaScript code designed to mine cryptocurrency. Once the website is opened, the script executes and starts mining Monero. The script employs the system to solve various mathematical "equations".
A reward for solving the equation is a fraction of a Monero coin (since an identical "equation" is solved by a number of computers, the coin is distributed amongst them). In fact, users receive nothing - the reward goes to the developers.
The idea of Crypto-Loot is legitimate - developers have an additional way to monetize their sites, however, as mentioned above, some become greedy and take advantage of unsuspecting users. Some cyber criminals hijack legitimate websites and stealthily embed the Crypto-Loot script.
In addition, they develop sites (that typically contain fake error messages or random content) and inject them with Crypto-Loot. These sites are also likely to contain scripts that prevent users from closing the browsing tabs/windows. This is done to prevent users from leaving sites - the longer the user stays, the more cryptocurrency is mined.
Crypto-Loot provides a feature allowing to set a limit of system resources that should be used, however, criminals typically remove it. JavaScript makes perfect use of computer CPUs. Therefore, since there are no limits, CPU usage typically reaches 100% and the system becomes virtually unusable and unstable (it can crash, resulting in permanent data loss).
In addition, within certain circumstances (e.g., high room temperature, bad cooling system, etc.) a CPU that works at 100% can simply overheat. Note that a single home PC is not very effective for mining cryptocurrency (the cost of electricity consumed is higher than revenue received). In addition, users generally only stay on injected sites for just a few minutes.
Therefore, cyber criminals promote these sites using potentially unwanted adware-type programs (PUPs) that deliver intrusive advertisements. In summary, Crypto-Loot service is legitimate and useful for web developers, but often abused. From the user's point of view, Crypto-Loot is dubious and unwanted.
Adware generates pop-up (new browser windows), banner, and other intrusive ads using tools that enable placement of third party graphical content on any site. Some of these ads redirect to malicious sites that mine cryptocurrencies and contain malicious content or even scripts that download/install malware.
Therefore, clicking these ads can result in high-risk computer infections. Data tracking is also an issue. These programs often gather information that includes personal details.
Collected data is shared with third parties (potentially, cyber criminals) who misuse private information to generate revenue. Therefore, the presence of information-tracking apps can lead to serious privacy issues or even identity theft. You are strongly advised to uninstall PUPs immediately.
| Name | Crypto-Loot malware |
| Threat Type | Adware, Unwanted ads, Pop-up Virus |
| Symptoms | Seeing advertisements not originating from the sites you are browsing. Intrusive pop-up ads. Decreased Internet browsing speed. |
| Distribution methods | Deceptive pop-up ads, free software installers (bundling), fake flash player installers. |
| Damage | Decreased computer performance, browser tracking - privacy issues, possible additional malware infections. |
| Malware Removal (Windows) | To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. |
Many adware-type PUPs are virtually identical. By offering "useful features", PUPs attempt to give the impression of legitimacy, however, since all PUPs are designed to generate passive revenue, regular users receive no real value. Rather than enabling the functions promised, adware poses a direct threat to your privacy and Internet browsing safety.
How did potentially unwanted programs install on my computer?
Some PUPs have official download/promotion websites, however, due to the lack of knowledge and careless behavior of many users, adware typically infiltrates systems without permission. These programs are proliferated using intrusive advertising, and a deceptive marketing method called "bundling" (stealth installation of third party apps together with regular software/apps).
Developers do not disclose these installations properly - they hide "bundled" apps within "Custom/Advanced" settings or other sections of the download/installation processes. In addition, many users click ads and skip download/installation steps. In doing so, they expose their systems to risk of various infections and compromise their privacy.
How to avoid installation of potentially unwanted applications?
To prevent system infiltration by adware, be very cautious when browsing the Internet and downloading/installing software. Intrusive ads may seem legitimate, but redirect to gambling, adult dating, pornography, and other suspicious sites. If you experience these redirects, immediately eliminate all dubious applications.
Furthermore, carefully analyze each window of the download/installation processes and opt-out of all additionally-included programs. You are advised to download your apps from official sources only using direct download links, since third party downloaders/installers are monetized using the "bundling" method (they promote dubious apps).
Usage of computer CPU once a website with Crypto-Loot script is opened:
A rogue site using Crypto-Loot script:
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 Crypto-Loot?
- STEP 1. Uninstall deceptive applications using Control Panel.
- STEP 2. Remove adware from Internet Explorer.
- STEP 3. Remove rogue extensions from Google Chrome.
- STEP 4. Remove potentially unwanted plug-ins from Mozilla Firefox.
- STEP 5. Remove rogue extensions from Safari.
- STEP 6. Remove rogue plug-ins from Microsoft Edge.
Removal of potentially unwanted programs:
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 suspicious/recently-installed applications, select these entries and click "Uninstall" or "Remove".
After uninstalling the potentially unwanted program, scan your computer for any remaining unwanted components or possible malware infections. To scan your computer, use recommended malware removal software.
Remove rogue extensions from Internet browsers:
Video showing how to remove potentially unwanted browser add-ons:
Remove malicious add-ons from Internet Explorer:
Click the "gear" icon 
(at the top right corner of Internet Explorer), select "Manage Add-ons". Look for any recently-installed suspicious browser extensions, select these entries and click "Remove".
Optional method:
If you continue to have problems with removal of the crypto-loot malware, reset your Internet Explorer settings to default.
Windows XP users: Click Start, click Run, in the opened window type inetcpl.cpl In the opened window click the Advanced tab, then click Reset.
Windows Vista and Windows 7 users: Click the Windows logo, in the start search box type inetcpl.cpl and click enter. In the opened window click the Advanced tab, then click Reset.
Windows 8 users: Open Internet Explorer and click the gear icon. Select Internet Options.
In the opened window, select the Advanced tab.
Click the Reset button.
Confirm that you wish to reset Internet Explorer settings to default by clicking the Reset button.
Remove malicious extensions from Google Chrome:
Click the Chrome menu icon 
(at the top right corner of Google Chrome), select "More tools" and click "Extensions". Locate all recently-installed suspicious browser add-ons, select these entries and click the trash can icon.
Optional method:
If you continue to have problems with removal of the crypto-loot malware, 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". Click on "Extensions", in the opened window, remove all recently-installed suspicious browser plug-ins.
Optional method:
Computer users who have problems with crypto-loot malware 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 crypto-loot malware, 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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Outstanding!
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