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JS:Cryptonight virus. How to remove? (Uninstall guide)

removal by Lucia Danes - - | Type: Malware

JS:Cryptonightminer – yet another miner that misuses computer's resources to generate Monero 

JS:Cryptonight virus mines Monero
JS:Cryptonight is categorized as one of Monero crypto-miners.

Questions about JS:Cryptonight virus

JS:Cryptonight is a trojan horse that used to mine Monero cryptocurrency. The unique feature of malware is that it can affect both Windows and Mac operating systems. The trojan might enter the system unnoticed and immediately start using GPU and CPU of the affected device for illegal cryptocurrency mining. JS:Cryptonight miner is known to run on JavaScript which is activated for mining right after the victim is tricked into clicking the malicious link or downloads the infected email attachment. Unfortunately, keeping this program on the system can also lead its victim to the loss of personal information and infiltration of other malware.

Name JS:Cryptonight
Type Trojan horse/cryptominer
SYSTEMS AFFECTED Windows, Mac OS X
Danger level Medium. Initiates system changes, misuses computer's CPU and GPU for crypto mining
Symptoms Sluggish computer's performance, unknown processes running in the Task Manager
Distribution methods Bogus downloads, corrupted websites
Main dangers Computer damage, the loss of personal information
Elimination To get rid of this trojan virus, use Reimage

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. 

Trojan 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 virus image
JS: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.[1] It is specially designed to mine Monero cryptocurrency which gains more and more popularity[2]. You can suspect that it was installed on your Mac or Windows computer if you see suspicious processes running in the Task Manager and notice sluggish computer’s 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 NEVER 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:Cryptonight picture
JS: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, like Reimage. At the moment, AVG is detecting this virus as JS:CryptonightMiner-a. 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 miner
Systems 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 example
There 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.

Additionally, experts from LosVirus.es[3] 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 or Plumbytes Anti-MalwareMalwarebytes 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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If you failed to remove virus damage using Reimage, submit a question to our support team and provide as much details as possible.
Reimage is recommended to remove virus damage. Free scanner allows you to check whether your PC is infected or not. If you need to remove malware, you have to purchase the licensed version of Reimage malware removal tool.
More information about this program can be found in Reimage review.

If you decided to select another anti-spyware, uninstall Reimage from your computer.
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Alternative Software
Different security software includes different virus database. If you didn’t succeed in finding malware with Reimage, try running alternative scan with Malwarebytes.
Alternative Software
Different security software includes different virus database. If you didn’t succeed in finding malware with Reimage, try running alternative scan with 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 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 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, Malwarebytes MalwarebytesCombo Cleaner or Plumbytes Anti-MalwareMalwarebytes Malwarebytes

About the author

Lucia Danes
Lucia Danes - Virus researcher

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References

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