THREAT REMOVAL

What is JS:Cryptonight Miner Virus and How to Remove It

This article has been created in order to help you by demonstrating how to remove the JS:Cryptonight miner for the cryptocurrency Monero and how to protect your MacBook against future miners as well.

SIDENOTE: This post was originally published in August 2018. But we gave it an update in August 2019.

A new cryptocurrency miner, this time exclusively for MacBooks, which mines for the crytpocurrency Monero. The miner runs on JavaScript and is known as the algorithm Cryptonight it uses to mine for the Monero cryptocurrency. Once this malware infects your computer it may begin to slow it down by heavily using it’s CPU as well as GPU resources in order to generate Monero at your Mac’s expense. If you believe that your computer has been infected by the JS:Cryptonight crypto mining malware, we advise you to read this article and learn how to remove it from your computer.

Threat Summary

Name JS:Cryptonight
Type Cryptocurrency mining malware.
Short Description Runs on JavaScript code and mines for the cryptocurrency Monero.
Symptoms May overheat your CPU and GPU by using them to mine for the cryptocurrency Monero.
Distribution Method Via malicous web links, e-mails and other third-party content.
Detection Tool See If Your System Has Been Affected by malware

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User Experience Join Our Forum to Discuss JS:Cryptonight.

JS:Cryptonight Malware – Spread

In order to infect the maximum amount of victims, the virus files of this malware may be spread in a multitude of methods. These include spreading the malicious files by sending malicious spam e-mails as well as other content to you online. These e-mails often contain false statements to get you to click on a web link or download a malicious attachmnent, for example:

Once the victim clicks on the web link, a JavaScript is activated and the virus may begin to perform it’s malicious activity by downloading and executing a process in your MacBook or running filelessly.

JS:Cryptonight – More Information

Once this malware is activated on your computer, it may drop it’s malicious processes and they may have different names on your computer. The file are usually located in various commonly targeted directories or ran filelessly.

After the malicious files, belonging to JS:Cryptonight are ran, the virus may obtain administrative permissions, touch system files as well as create mutexes. Then, the JS:Cryptonight runs a malicious process in the background of your computer, which may result in your CPU usage spiking severely.


Image Source: MakeUseOf.com

In addition to this, since it is malware after all, the JS:Cryptonight may also perform other activities on your computer system, such as:

  • Update itself.
  • Download other malware.
  • Collect important information from your computer system.

Be advised that the miner primarily targets the GPU of your MacBook since it uses the Cryptonight algorithm which is a proof of work and utilized to mine exclusively for Monero. The way the mining process occurs is by getting the MacBook to be enlisted in a so-called mining pool. This makes it possible to turn the infected device into a miner and generate crypto money for the cyber-criminals at your PC’s expense. Since the process is particularly dangerous and can even damage your computer in the long-term, security experts strongly advise to remove it from your computer.

Remove JS:Cryptonight from Your Computer

In order to remove the JS:Cryptonight from your computer, we recommend that you do this automatically, since manual removal requires an extensive experience in this field. To do this, you can use Kaspersky’s latest security software against miner malware, like JS:Cryptonight, which besides removing the virus at a click of a button will also make sure that your Mac stays protected against future infections as well.

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Ventsislav Krastev

Ventsislav is a cybersecurity expert at SensorsTechForum since 2015. He has been researching, covering, helping victims with the latest malware infections plus testing and reviewing software and the newest tech developments. Having graduated Marketing as well, Ventsislav also has passion for learning new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management, Network Administration and Computer Administration of System Applications, he found his true calling within the cybersecrurity industry and is a strong believer in the education of every user towards online safety and security.

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OFFER
REMOVE IT NOW (MAC)
with SpyHunter for Mac
JS:Cryptonight may remain persistent on your system and may re-infect it. We recommend you to download SpyHunter for Mac and run free scan to remove all virus files on your Mac. This saves you hours of time and effort compared to doing the removal yourself.
Free Remover allows you, subject to a 48-hour waiting period, one remediation and removal for results found. Read EULA and Privacy Policy

Preparation Phase:

Before starting to follow the steps below, be advised that you should first do the following preparations:

  • Backup your files in case the worst happens.
  • Make sure to have a device with these instructions on standy.
  • Arm yourself with patience.

Step 1: Uninstall JS:Cryptonight and remove related files and objects

OFFER
Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!
We Recommend To Scan Your Mac with SpyHunter for Mac
Keep in mind, that SpyHunter for Mac needs to purchased to remove the malware threats. Click on the corresponding links to check SpyHunter’s EULA and Privacy Policy


1. Hit the ⇧+⌘+U keys to open Utilities. Another way is to click on “Go” and then click “Utilities”, like the image below shows:


2. Find Activity Monitor and double-click it:


3. In the Activity Monitor look for any suspicious processes, belonging or related to JS:Cryptonight:

Tip: To quit a process completely, choose the “Force Quit” option.


4. Click on the "Go" button again, but this time select Applications. Another way is with the ⇧+⌘+A buttons.


5. In the Applications menu, look for any suspicious app or an app with a name, similar or identical to JS:Cryptonight. If you find it, right-click on the app and select “Move to Trash”.


6. Select Accounts, after which click on the Login Items preference. Your Mac will then show you a list of items that start automatically when you log in. Look for any suspicious apps identical or similar to JS:Cryptonight. Check the app you want to stop from running automatically and then select on the Minus (“-“) icon to hide it.


7. Remove any left-over files that might be related to this threat manually by following the sub-steps below:

  • Go to Finder.
  • In the search bar type the name of the app that you want to remove.
  • Above the search bar change the two drop down menus to “System Files” and “Are Included” so that you can see all of the files associated with the application you want to remove. Bear in mind that some of the files may not be related to the app so be very careful which files you delete.
  • If all of the files are related, hold the ⌘+A buttons to select them and then drive them to “Trash”.

In case you cannot remove JS:Cryptonight via Step 1 above:

In case you cannot find the virus files and objects in your Applications or other places we have shown above, you can manually look for them in the Libraries of your Mac. But before doing this, please read the disclaimer below:

Disclaimer! If you are about to tamper with Library files on Mac, be sure to know the name of the virus file, because if you delete the wrong file, it may cause irreversible damage to your MacOS. Continue on your own responsibility!

1. Click on "Go" and Then "Go to Folder" as shown underneath:

2. Type in "/Library/LauchAgents/" and click Ok:

3. Delete all of the virus files that have similar or the same name as JS:Cryptonight. If you believe there is no such file, do not delete anything.

You can repeat the same procedure with the following other Library directories:

→ ~/Library/LaunchAgents
/Library/LaunchDaemons

Tip: ~ is there on purpose, because it leads to more LaunchAgents.


Step 2: Remove JS:Cryptonight – related extensions from Safari / Chrome / Firefox

Remove an extension from Safari and reset it.Remove a toolbar from Google Chrome Remove a toolbar from Mozilla Firefox

1. Start Safari

2. After hovering your mouse cursor to the top of the screen, click on the Safari text to open its drop down menu.

3. From the menu, click on "Preferences"

stf-safari preferences

4. After that, select the 'Extensions' Tab

stf-safari-extensions

5. Click once on the extension you want to remove.

6. Click 'Uninstall'

stf-safari uninstall

A pop-up window will appear asking for confirmation to uninstall the extension. Select 'Uninstall' again, and the JS:Cryptonight will be removed.

How to Reset Safari
IMPORTANT: Before resetting Safari make sure you back up all your saved passwords within the browser in case you forget them.

Start Safari and then click on the gear leaver icon.

Click the Reset Safari button and you will reset the browser.

1. Start Google Chrome and open the drop menu

2. Move the cursor over "Tools" and then from the extended menu choose "Extensions"

3. From the opened "Extensions" menu locate the add-on and click on the garbage bin icon on the right of it.

4. After the extension is removed, restart Google Chrome by closing it from the red "X" in the top right corner and start it again.


1. Start Mozilla Firefox. Open the menu window

2. Select the "Add-ons" icon from the menu.

3. Select the Extension and click "Remove"

4. After the extension is removed, restart Mozilla Firefox by closing it from the red "X" in the top right corner and start it again.


Step 3: Scan for and remove JS:Cryptonight files from your Mac

When you are facing problems on your Mac as a result of unwanted scripts and programs such as JS:Cryptonight, the recommended way of eliminating the threat is by using an anti-malware program. SpyHunter for Mac offers advanced security features along with other modules that will improve your Mac’s security and protect it in the future.


Click the button below below to download SpyHunter for Mac and scan for JS:Cryptonight:


Download

SpyHunter for Mac




JS:Cryptonight FAQ

What is JS:Cryptonight on your Mac?

The JS:Cryptonight threat is a potentially unwanted app or likely a Mac virus. It may slow your Mac down siginficantly and display advertisements. The main idea is for your information to likely get stolen or more ads to appear on your Mac.

The creators of such unwanted apps work with pay-per-click schemes to get your Mac to visit risky or different types of websites that may generate them funds. This is why they do not even care what types of websites show up on the ads. This makes their unwanted software indirectly risky for your MacOS.

Can my Mac get a virus?

Yes. As much as any other device, Apple computers do get viruses. Apple devices may not be a frequent target by malware authors, but rest assured that the following Apple devices can become infected with a virus:

  • iMac
  • Mac Mini
  • Macbook Air
  • Macbook Pro
  • iPhone
  • iPad

What are the symptoms of JS:Cryptonight on your Mac?

There are several symptoms to look for when this particular threat and also most Mac threats in general are active:

Symptom #1: Your Mac may become slow and has poor performance in general.

Symtpom #2: You have toolbars, add-ons or extensions on your web browsers that you don't remember adding.

Symptom #3: You see all types of ads, like ad-supported search results, pop-ups and redirects to randomly appear.

Symptom #4: You see installed apps on your Mac running automatically and you do not remember installing them.

Symptom #5: You see suspicious processes running in your Mac's Activity Monitor.

If you see one or more of those symptoms, then security experts reccomend that you check your Mac for viruses.

What types of Mac threats are there?

According to most malware researchers and cyber-security experts, the threats that can currently infect your Mac can be the following types:

  • Rogue Antivirus programs.
  • Adware and hijackers.
  • Trojan horses and other spyware.
  • Ransomware and screen-lockers.
  • Cryptocurrency miner malware.

What to do if I have a Mac virus, like JS:Cryptonight?

Do not panic! You can easily get rid of most Mac threats by firstly isolating them and then removing them. One reccomended way to do that is by using a reputable malware removal software that can take care of the removal automatically for you. There are many Mac anti-malware apps out there that you can choose from. SpyHunter for Mac is one of the reccomended Mac anti-malware apps, that can scan for free and detect any viruses, tracking cookies and unwanted adware apps plus take care of them quickly. This saves time for manual removal that you would otherwise have to do.

How to secure my passwords and other data from JS:Cryptonight?

With few simple actions. First and foremost, it is imperative that you follow these steps:

Step 1: Find a safe computer and connect it to another network, not the one that your Mac was infected in.

Step 2: Change all of your passwords, starting from your e-mail passwords.

Step 3: Enable two-factor authentication for protection of your important accounts.

Step 4: Call your bank to change your credit card details (secret code, etc.) if you have saved your credit card for online shopping or have done online activiites with your card.

Step 5: Make sure to call your ISP (Internet provider or carrier) and ask them to change your IP address.

Step 6: Change your Wi-Fi password.

Step 7: (Optional): Make sure to scan all of the devices connected to your network for viruses and repeat these steps for them if they are affected.

Step 8: Install anti-malware software with real-time protection on every device you have.

Step 9: Try not to download software from sites you know nothing about and stay away from low-reputation websites in general.

If you follow these reccomendations, your network and Apple devices will become significantly more safe against any threats or information invasive software and be virus free and protected in the future too.

More tips you can find on our website, where you can also ask any questions and comment about your Mac problems.

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