How to remove BottomLoader malware

Also Known As: BottomLoader malware dropper
Type: Trojan
Damage level: Severe

What kind of malware is BottomLoader?

BottomLoader is a DLang-based malware downloader that plays a role in the initial stages of a cyber attack by facilitating the retrieval and execution of subsequent malicious payloads. This malware is designed to deliver additional malware or tools onto the compromised system, expanding the attacker's foothold and enabling further exploitation.

BottomLoader malware

More about BottomLoader

Threat actors have been observed using BottomLoader as a tool to distribute malware called HazyLoad. BottomLoader downloads the payload from a remote URL using a PowerShell command. The loader has the capability to establish persistence for either updated versions or entirely new subsequent payloads. It achieves this by generating a ".URL" file within the Startup directory.

Cybercriminals may also use the BottomLoader malware to distribute various malicious payloads, expanding the scope of their attacks. This versatile tool may serve as a conduit for various threats, including ransomware that encrypts files and extorts ransom payments.

By leveraging BottomLoader, attackers can also initiate Trojan deployments, encompassing banking trojans or remote access trojans (RATs) designed to pilfer sensitive information or enable remote control over compromised systems.

Additionally, BottomLoader may be used to deliver spyware, allowing cybercriminals to stealthily monitor and harvest information from infected systems or cryptocurrency miners, enabling threat actors to mine cryptocurrency using the hardware of infected computers.

Threat Summary:
Name BottomLoader malware dropper
Threat Type Malware Loader
Detection Names Avast (Win64:DropperX-gen [Drp]), Combo Cleaner (Gen:Variant.Lazy.429418), ESET-NOD32 (A Variant Of Win64/Andariel.P), Kaspersky (Trojan.Win64.Agent.qwiwlo), Microsoft (Trojan:Win32/Wacatac.B!ml), Full List (VirusTotal)
Payload HazyLoad and possibly other malware
Symptoms Loaders are designed to stealthily infiltrate the victim's computer and remain silent, and thus no particular symptoms are clearly visible on an infected machine.
Distribution methods Software vulnerabilities, infected email attachments, malicious online advertisements, social engineering, software 'cracks'.
Damage Stolen passwords and banking information, identity theft, the victim's computer added to a botnet, monetary loss, etc.
Malware Removal (Windows)

To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner.
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In conclusion, BottomLoader emerges as a potent and adaptable malware tool employed by cybercriminals to orchestrate a diverse array of malicious activities. Its ability to establish persistence, download subsequent payloads, and serve as a versatile conduit for various types of malware underscores the importance of mitigating the risks associated with this malware.

How did BottomLoader infiltrate my computer?

The perpetrators behind BottomLoader have been seen exploiting the Log4Shell vulnerability to distribute the malware. After successfully exploiting this vulnerability, attackers acquire initial access to the system and then conduct malicious activities (inject additional payloads).

Cybercriminals also use phishing emails containing malicious links or attachments, malicious advertisements, peer-to-peer or file-sharing networks, compromised websites, pirated software, cracking tools, and similar channels to deliver malware. Usually, their goal is to lure users into downloading and executing malware

How to avoid installation of malware?

Regularly update operating systems, applications, and antivirus software to patch vulnerabilities and enhance security. Use reputable antivirus or anti-malware software and run system scans regularly. Exercise caution when dealing with emails, especially those from unknown senders containing links or files.

Avoid clicking suspicious links, pop-ups, and ads, and only download files from trusted sources (official pages and app stores).

If you believe that your computer is already infected, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

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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How to remove malware manually?

Manual malware removal is a complicated task - usually it is best to allow antivirus or anti-malware programs to do this automatically. To remove this malware we recommend using Combo Cleaner Antivirus for Windows.

If you wish to remove malware manually, the first step is to identify the name of the malware that you are trying to remove. Here is an example of a suspicious program running on a user's computer:

Malware process running in the Task Manager

If you checked the list of programs running on your computer, for example, using task manager, and identified a program that looks suspicious, you should continue with these steps:

manual malware removal step 1Download a program called Autoruns. This program shows auto-start applications, Registry, and file system locations:

Autoruns application appearance

manual malware removal step 2Restart your computer into Safe Mode:

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Run Windows 7 or Windows XP in Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup.

Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings".

Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Run Windows 8 in Safe Mode with Networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options".

In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

Run Windows 10 in Safe Mode with Networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

manual malware removal step 3Extract the downloaded archive and run the Autoruns.exe file.

Extract Autoruns.zip archive and run Autoruns.exe application

manual malware removal step 4In the Autoruns application, click "Options" at the top and uncheck "Hide Empty Locations" and "Hide Windows Entries" options. After this procedure, click the "Refresh" icon.

Refresh Autoruns application results

manual malware removal step 5Check the list provided by the Autoruns application and locate the malware file that you want to eliminate.

You should write down its full path and name. Note that some malware hides process names under legitimate Windows process names. At this stage, it is very important to avoid removing system files. After you locate the suspicious program you wish to remove, right click your mouse over its name and choose "Delete".

Delete malware in Autoruns

After removing the malware through the Autoruns application (this ensures that the malware will not run automatically on the next system startup), you should search for the malware name on your computer. Be sure to enable hidden files and folders before proceeding. If you find the filename of the malware, be sure to remove it.

Search for malware and delete it

Reboot your computer in normal mode. Following these steps should remove any malware from your computer. Note that manual threat removal requires advanced computer skills. If you do not have these skills, leave malware removal to antivirus and anti-malware programs.

These steps might not work with advanced malware infections. As always it is best to prevent infection than try to remove malware later. To keep your computer safe, install the latest operating system updates and use antivirus software. To be sure your computer is free of malware infections, we recommend scanning it with Combo Cleaner Antivirus for Windows.

Frequently Asked Questions (FAQ)

My computer is infected with BottomLoader malware, should I format my storage device to get rid of it?

Formatting your storage device may be a drastic step and should be considered carefully. Before proceeding with formatting, use a reputable antivirus or anti-malware program like Combo Cleaner to thoroughly scan your system. Allow the software to detect and remove the BottomLoader malware.

What are the biggest issues that malware can cause?

Malware poses severe threats, causing issues such as data loss, system disruption, financial losses, identity theft, network compromise, reputational damage, legal consequences, operational downtime, and intellectual property theft.

What is the purpose of BottomLoader?

The primary purpose of BottomLoader is to serve as a malware delivery mechanism, facilitating the download and execution of various malicious payloads onto compromised systems.

How did BottomLoader infiltrate my computer?

The creators of BottomLoader exploit the Log4Shell vulnerability to distribute malware, gaining initial access to systems for malicious activities. Also, they may employ phishing emails with malicious links or attachments, malicious ads, peer-to-peer networks, compromised websites, pirated software, and cracking tools to distribute malware.

Will Combo Cleaner protect me from malware?

Certainly, Combo Cleaner can identify and remove nearly all known malware infections. Sophisticated malware can be capable of concealing itself deeply within the system. Therefore, conducting a comprehensive system scan is necessary to eliminate such malware.

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About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for pcrisk.com since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

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Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

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