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Remove JS:Cryptonight virus (Removal Guide) - updated Oct 2020

removal by Lucia Danes - - | Type: Mac viruses

JS:Cryptonightminer is the name Avast and AVG vendors give malicious crypto-mining script embedded on various sites, although can also be a false-positive

JS:Cryptonight virus mines Monero

JS:Cryptonight is a cryptominer that uses Cryptonight algorithm to mine Monero and is based on JavaScript.[1] The unique feature of malware is that it can affect both Windows and Mac operating systems. The trojan might enter the system via malicious spam emails or other stealthy methods and immediately start utilizing the GPU and CPU of the affected device for illegal cryptocurrency mining. The mined funds are immediately transferred to a preset crypto wallet, generating money regularly for the threat actors behind the JS:Cryptonight malware.

While the detection might mean that your browsers are infected, it can also be a false-positive,[2] as users reported that they were getting the JS: CryptoNightMiner-A [Trj] alert on legitimate sites like YouTube. In such a case, it is recommended updating Google Chrome, Mozilla Firefox, or another users browser along with AVG or Avast security software to stop false alarms.

Questions about JS:Cryptonight virus

If, however, the infection is present it is vital to get rid of JS:Cryptonight miner as soon as possible, as its malicious background processes might compromise the computer security and result in further malware infections, wear out the hardware, and also result in increased electricity bills. For that, please scan your computer with reputable anti-malware software as soon as possible.

Name JS:Cryptonight
Also known as JS: CryptoNightMiner-A [Trj], JS:CryptonightMiner-a
Type Trojan horse/cryptominer
Danger level Medium. Initiates system changes, misuses computer's CPU and GPU for crypto mining
Symptoms Sluggish computer performance, unknown processes running in the Task Manager
Distribution methods Bogus downloads, corrupted websites
Main dangers Computer hardware damage, other malware infection, infiltration of other malware
Elimination To get rid of this trojan virus, use Reimage Reimage Cleaner Intego

As we have mentioned, JS:Cryptonight virus might enter the system after downloading the malicious email attachment. However, it can also infect it after visiting a questionable website, for instance, illegal video streaming or web game site. If you have antivirus installed on your PC and it is up-to-date, it is supposed to warn you about such activity. 

JS: CryptoNightMiner-A [Trj] might also get into the system pretending to be a legitimate program or its update. Hence, the miner might be installed after downloading freeware or shareware. In this case, the malicious program initiates system changes and immediately starts using computer’s resources to mine cryptocurrency.

JS:Cryptonight virusJS:Cryptonight is a term used by many antivirus programs to identify a cyber threat on the system.

The miner runs on a Javascript algorithm called Cryptonight.[3] It is specially designed to mine Monero cryptocurrency which gains more and more popularity[4]. You can suspect that it was installed on your Mac or Windows computer if you see suspicious processes running in the Task Manager/Activity Monitor and notice sluggish computer performance. Sometimes the mining is initiated while visiting specific websites. In this case, the process should stop once you close these sites and leave them.

In case you believe you are infected, you should not try to remove JS:Cryptonight manually. Malware might consist of numerous different files which have to be erased as well. Additionally, other malicious programs may have been installed on your device too.

JS:CryptonightJS:Cryptonight generates illegal profits for its developers from mining Monero digital currency.

For this reason, it’s recommended opting for automatic JS:Cryptonight removal which requires scanning the system with anti-malware tool, such as Reimage Reimage Cleaner Intego. At the moment, AVG is detecting this virus as JS:CryptonightMiner-a or JS: CryptoNightMiner-A [Trj]. This task should not be delayed because, as you might have already understood, the virus can lead your PC to the loss of valuable information and similar issues. Such cyber threats have unlimited abilities, so make sure you keep an eye on them.

The dangers of JS:Cryptonight

Even though it is hard to identify that your system is infected with JS:Cryptonight virus, users report about multiple issues which are caused by this cyber threat in the long-run. Usually, a computer becomes noticeably slower and fails to load specific applications on a daily basis.

JS:Cryptonight minerSystems infected with JS:Cryptonight virus might start to crash, freeze or make browsing experience unbearable.

It is because JS:Cryptonight miner exploits high amounts of computing power to mine Monero digital currency. In other terms, the system is forced to reallocate all its resources to cryptocurrency mining for long periods of time. As a result, it operates at high temperatures for excessive amounts of time and has little resources left for essential processes.

Likewise, if JS:Cryptonight sneaks into your system, there is a substantial risk that you will face the following problems:

  • Increased latency;
  • Some programs might not load;
  • System crash;
  • Never-ending freezes.

JS:Cryptonight infection exampleThere are numerous other infections similar to JS:Cryptonight miner.

Furthermore, these are not the only dangers of JS:Cryptonight attack. Keep in mind that all infections, including crypto-malware, make computer's system vulnerable to other dangerous viruses. Thus, the presence of this Monero miner might increase the risk of occurrence of other potentially malicious programs. 

Infiltration of cryptocurrency miner

The trojan horse might enter the system using a couple of methods. However, each of them requires user’s participation. Typically, malware is advertised as useful program or software update. Hence, users might install it themselves.

Usually, such programs are available on unauthorized file-sharing websites, P2P networks, torrents and similar questionable sources. For this reason, users are advised to stay away from such places. If you need a particular program, you should rely on developer’s websites only.

JS:Cryptonight malwareJS:Cryptonight virus targets Windows and Mac computers to mine Monero illegally.

Additionally, experts from[5] remind that it’s important to pay attention to software installation process too. If you decide to install freeware or shareware, you need to use Advanced/Custom settings and opt out all pre-selected optional programs. Usually, they have more negative features than are beneficial to the user.

Keep in mind that Quick/Recommended settings do reveal what is hiding in the software bundle. Hence, if you use them, you give indirect permission to install all third-party applications without even knowing it.

Delete JS:Cryptonight virus from the machine

To remove JS:Cryptonight trojan virus from Mac or Windows correctly, you have to use powerful security software, such as Reimage Reimage Cleaner Intego or Malwarebytes. It doesn’t matter whether malware infected Mac or Windows device, automatic removal is the only safe method to remove cryptocurrency miner.

Manual JS Cryptonight trojan removal might not be effective. The miner might come back and continue its activities once you reboot the computer. Additionally, you might accidentally terminate legitimate system files which may lead to irreparable damage to the system.

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What to do if failed?
If you failed to remove virus damage using Reimage Intego, submit a question to our support team and provide as much details as possible.
Reimage Intego has a free limited scanner. Reimage Intego offers more through scan when you purchase its full version. When free scanner detects issues, you can fix them using free manual repairs or you can decide to purchase the full version in order to fix them automatically.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Reimage, try running SpyHunter 5.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Intego, try running Combo Cleaner.

To remove JS:Cryptonight virus, follow these steps:

Remove JS:Cryptonight using Safe Mode with Networking

If JS:Cryptonight is blocking access to security software, follow these steps and get rid of this virus with the help of Safe Mode with Networking:

  • Step 1: Reboot your computer to Safe Mode with Networking

    Windows 7 / Vista / XP
    1. Click Start Shutdown Restart OK.
    2. When your computer becomes active, start pressing F8 multiple times until you see the Advanced Boot Options window.
    3. Select Safe Mode with Networking from the list Select 'Safe Mode with Networking'

    Windows 10 / Windows 8
    1. Press the Power button at the Windows login screen. Now press and hold Shift, which is on your keyboard, and click Restart..
    2. Now select Troubleshoot Advanced options Startup Settings and finally press Restart.
    3. Once your computer becomes active, select Enable Safe Mode with Networking in Startup Settings window. Select 'Enable Safe Mode with Networking'
  • Step 2: Remove JS:Cryptonight

    Log in to your infected account and start the browser. Download Reimage Reimage Cleaner Intego or other legitimate anti-spyware program. Update it before a full system scan and remove malicious files that belong to your ransomware and complete JS:Cryptonight removal.

If your ransomware is blocking Safe Mode with Networking, try further method.

Remove JS:Cryptonight using System Restore

This method might also help to get rid of this Trojan virus with the help of System Restore method:

  • Step 1: Reboot your computer to Safe Mode with Command Prompt

    Windows 7 / Vista / XP
    1. Click Start Shutdown Restart OK.
    2. When your computer becomes active, start pressing F8 multiple times until you see the Advanced Boot Options window.
    3. Select Command Prompt from the list Select 'Safe Mode with Command Prompt'

    Windows 10 / Windows 8
    1. Press the Power button at the Windows login screen. Now press and hold Shift, which is on your keyboard, and click Restart..
    2. Now select Troubleshoot Advanced options Startup Settings and finally press Restart.
    3. Once your computer becomes active, select Enable Safe Mode with Command Prompt in Startup Settings window. Select 'Enable Safe Mode with Command Prompt'
  • Step 2: Restore your system files and settings
    1. Once the Command Prompt window shows up, enter cd restore and click Enter. Enter 'cd restore' without quotes and press 'Enter'
    2. Now type rstrui.exe and press Enter again.. Enter 'rstrui.exe' without quotes and press 'Enter'
    3. When a new window shows up, click Next and select your restore point that is prior the infiltration of JS:Cryptonight. After doing that, click Next. When 'System Restore' window shows up, select 'Next' Select your restore point and click 'Next'
    4. Now click Yes to start system restore. Click 'Yes' and start system restore
    Once you restore your system to a previous date, download and scan your computer with Reimage Reimage Cleaner Intego and make sure that JS:Cryptonight removal is performed successfully.

Finally, you should always think about the protection of crypto-ransomwares. In order to protect your computer from JS:Cryptonight and other ransomwares, use a reputable anti-spyware, such as Reimage Reimage Cleaner Intego, SpyHunter 5Combo Cleaner or Malwarebytes

Access your website securely from any location

When you work on the domain, site, blog, or different project that requires constant management, content creation, or coding, you may need to connect to the server and content management service more often. It is a hassle when your website is protected from suspicious connections and unauthorized IP addresses.

The best solution for creating a tighter network could be a dedicated/fixed IP address. If you make your IP address static and set to your device, you can connect to the CMS from any location and do not create any additional issues for server or network manager that need to monitor connections and activities. This is how you bypass some of the authentications factors and can remotely use your banking accounts without triggering suspicious with each login. 

VPN software providers like Private Internet Access can help you with such settings and offer the option to control the online reputation and manage projects easily from any part of the world. It is better to clock the access to your website from different IP addresses. So you can keep the project safe and secure when you have the dedicated IP address VPN and protected access to the content management system.

Backup files for the later use, in case of the malware attack

Computer users can suffer from data losses due to cyber infections or their own faulty doings. Ransomware can encrypt and hold files hostage, while unforeseen power cuts might cause a loss of important documents. If you have proper up-to-date backups, you can easily recover after such an incident and get back to work. It is also equally important to update backups on a regular basis so that the newest information remains intact – you can set this process to be performed automatically.

When you have the previous version of every important document or project you can avoid frustration and breakdowns. It comes in handy when malware strikes out of nowhere. Use Data Recovery Pro for the data restoration process.

About the author
Lucia Danes
Lucia Danes - Virus researcher

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