Efsui.exe Virus ⛏️ (Coin Miner Trojan) Removal

Written by Robert Bailey
Efsui.exe process is related to a malevolent application that can properly be defined as a coin miner trojan. That malware form uses your hardware to mine cryptocurrencies, primarily – Monero or DarkCoin1. It makes your computer almost unusable due to high CPU usage.
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What is Efsui.exe process?

Efsui.exe is a malicious process created by coin miner virus

As I have actually specified in the previous paragraph, Efsui.exe is a coin miner trojan virus. The names of the .exe file can be different, but the consequences are almost always the same. Considering that coin miners aim at cryptocurrency mining, they use all available hardware capacity of your personal computer to conduct this operation. This virus does not pay attention to the fact that you probably need to use your PC for other activities – it will constantly consume over 80% of your CPU power.

Efsui.exe Windows Process

Efsui.exe – Extremely high CPU as well as GPU usage

Besides CPU usage, some of the coin miners additionally use GPU power for their tasks. In that situation, you will likely struggle even to see the mouse cursor moving – GPU is often utilized on 100%. It is not as critical as processor for system work, so Efsui.exe coin miner viruses do not waste time on trifles and utilize it all. It often may cause unhappy effects.

Shortly about cryptocurrency mining

Cryptocurrency mining is a term that means the activity of calculating the transaction block hash. That is a basic part of any project based on the blockchain technology. Since this operation takes a lot of calculations, a strong machine is required. Exactly, the GPU is better for this purpose, because they have more cores available. Cryptomining farms usually consist of dozens of GPUs to conduct their activity effectively. Such systems are not usable for “usual” purposes, like gaming or browsing the Web. Fraudsters who gain money via this coin miner use someones’ computers instead, even if they are used for the regular activity.2

List of the typical coin miner symptoms

  • Microsoft Defender is stopped;
  • CPU and GPU is loaded at 80-90% exactly after the system start
  • Cooling fans are running at high speed and create a lot of noise
  • A single process in Task Manager consumes all CPU and GPU power
  • How dangerous is the Efsui.exe miner?

    Coin miners does not deal damage to your files. However, they make a lot of unpleasant things with the whole system

    Initially, Efsui.exe virus makes your computer overloaded. It is unable to run your applications now, as all processor power is used by a virus. That malware does not care for your necessities, all it focuses on is making money on you. Even if you are patient, and you waited until browser is open, you will likely experience exceptionally sluggish performance. Pages can open for years, any kind of logins will likely take about a minute – just a horror story for a person that works online.

    Efsui.exe Technical Summary.

    File Name Efsui.exe
    Type Trojan Coin Miner
    Detection Name Trojan:Win32/CoinMiner
    Distribution Method Software bundling, Intrusive advertisement, redirects to shady sites etc.
    Similar behavior Dhcpsvchostdllcommon.exe, Microsoftconhost.exe, Temp.working
    Removal Download and install GridinSoft Anti-Malware for automatic Efsui.exe removal.

    “Visible” damage is not a single bad activity coin miners do to your PC. Efsui.exe coin miner additionally deals damage to your operating system. To conduct all malicious operations properly, it wrecks the security mechanisms of your system. You will likely see your Microsoft Defender disabled – malware halts it to prevent detection. If you open the HOSTS file, you will likely see a ton of new entries – they are brought in by this coin miner to connect your PC to a malicious mining network. All these changes shall be reverted to the initial state in the process of computer recovery.

    Hardware effects of coin miner activity

    Besides slowing down your computer, performing at peak power for a long period of time may trigger damage to your machine as well as increase power bills. Hardware components are created to easily deal with high load, but they are good with it only in case when they are in a good shape.

    Little and covered processor cooling system is not very easy to broke. Meanwhile, GPUs have big and easy-to-access fans, which can be easily broke if touched while spinning, for instance, by the user much before the malware injection. Malfunctioning cooling system, together with the very high load caused by Efsui.exe can easily lead to graphic card failure3. Graphic cards are also tend to have fast wearing when used for crypto mining. It is surely an undesirable situation when your GPU’s performance decreases on 20-30% just after 1-2 weeks of being exploited in such a way.

    How did I get Efsui.exe coin miner virus?

    Coin miners are spread through different ways, but their main sources are malicious banners and programs from dubious sources

    Coin miners are the most widespread malevolent programs through “severe” malware. Adware frequently serves as a carrier for Efsui.exe malware infiltration: it demonstrates you the banners, which contain a link to malware downloading. Yes, this abstract “malware” may belong to any type – yet another adware, spyware, rogue or backdoor. But the statistics show that approximately 30% of all malware spread through the malevolent banners are coin miners – and Efsui.exe is right among them.4

    Unwanted banners adware

    The example of malicious banners you can see in the Internet

    One more way you could get this item on your PC is by downloading it from the unreliable website as a part of a program. People who spread hacked versions of popular programs (which do not demand the license key) have small chances to get paid. For this reason, there is a very big lure to add in malware to the final package of the hacked application and get a coin for each setup. Before criticizing these people for hacking and also malware spreading, ask yourself – is it OK to avoid paying for the program in this manner? It is more affordable to pay $20-$30 one time than to pay a much bigger sum for antivirus program and new parts for your computer.

    How to remove the Efsui.exe miner from my PC?

    The best way to get rid of this coin miner virus is to use anti-malware software

    Eliminating such a virus involves the use of specific software. Effective anti-malware program must have high capability at scanning and be lightweight – in order to make no problems with utilization even on weak PCs. Furthermore, it is better to have on-run security in your protection solution – to stop the virus even before it starts. Microsoft Defender does not have these features for different factors. That’s why I’d recommend you to use a third-party anti-malware program for that reason. GridinSoft Anti-Malware is a perfect option that fits each of the specified qualities.5

    Prior to the virus removal, it is important to boot your system into Safe Mode with Networking. Since Efsui.exe miner consumes a lot of CPU power, it is needed to halt it before launching the security program. Otherwise, your scan will last for years, even though the GridinSoft program is pretty lightweight.

    Booting the PC into Safe Mode with Networking

    Press the Start button, then choose Power, and click on Reboot while holding the Shift key on the keyboard.

    Boot into Windows Safe Mode

    Windows will reboot into recovery mode. In that mode, choose Troubleshoot→ Startup Settings→ Safe Mode with Networking. Press the corresponding button on your keyboard to choose that option.

    windows safe mode boot option with command prompt

    When your system is in Safe Mode, all third-party apps, along with the majority of non-crucial system components, are not started with the system start. That allows you to clean the PC without dealing with high processor usage of the coin miner.

    Remove Efsui.exe coin miner virus with GridinSoft Anti-Malware

    Download and install GridinSoft Anti-Malware. You can use this anti-malware program for free during its 6-day trial period. In that term, all functions are available, and it takes no payments to remove malware from your system.

    GridinSoft Anti-Malware free trial

    After activating your free trial, start Full scan. It may last up to 10 minutes. You may use the PC as usual.

    Scanning in GridinSoft Anti-Malware

    When the scan is finished, press the Clean Now button to remove all detected elements from your system. This procedure takes less than a minute.

    GridinSoft Anti-Malware after the scan process

    Now, you are good to go. Reboot your PC into a normal Windows mode and use just as there was nothing malicious.

    Remove Efsui.exe Virus ⛏️ Trojan Coin Miner

    Name: Efsui.exe

    Description: The Efsui.exe is a Trojan Coin Miner that uses the infected computer’s sources to mine electronic money without your authorization. This Efsui.exe will create your CPU to go for very warm temperatures for prolonged periods of time, which could reduce the life of the CPU.

    Operating System: Windows

    Application Category: Trojan

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    References

    1. Read about why Monero and DarkCoin are so popular amongst cybercriminals.
    2. Detailed explanation of how does cryptomining work.
    3. About unwanted effects for GPUs in the process of cryptomining.
    4. Read more about various malware type on Cybersecurity Glossary.
    5. Our review on GridinSoft Anti-Malware.

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    About the author

    Robert Bailey

    I'm Robert Bailey, a passionate Security Engineer with a deep fascination for all things related to malware, reverse engineering, and white hat ethical hacking.

    As a white hat hacker, I firmly believe in the power of ethical hacking to bolster security measures. By identifying vulnerabilities and providing solutions, I contribute to the proactive defense of digital infrastructures.

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