How to remove Tropidoor malware from your operating system

What kind of malware is Tropidoor?

Tropidoor is a malicious program classed as a backdoor. Malware of this kind is designed to open a "backdoor" into systems, and some of these programs can download/install additional malicious software or components.

Tropidoor has been observed being used in campaigns that also utilized a downloader malware and a malicious program called BeaverTail. The latter is linked to North Korean threat actors.

Tropidoor malware overview

Tropidoor has been noted featuring in an attack chain initiated through spam emails promoting a malicious project on the BitBucket repository. It contained a downloader named "car.dll", and Tropidoor operated through this malware. The project also contained BeaverTail – another malicious program capable of causing chain infections and stealing sensitive data (e.g., log-in credentials, cryptowallets, etc.).

Tropidoor is loaded in-memory and operates as a backdoor – i.e., prepares the system for further infection and carries it out. This program first initiates contact with its C&C (Command and Control) server, to which it can then send collected data, receive commands, and issue command execution reports.

Tropidoor can execute various commands, including: gathering relevant device data (e.g., name, operating system info, hardware details, etc.), managing files (e.g., searching, getting file info, deleting, downloading/stealing, etc.), running/terminating processes, taking screenshots, and so on. This backdoor can also inject downloaded malicious content into processes (function as an injector) or load it in-memory.

It is pertinent to mention that malware developers often improve upon their software and methodologies. Hence, possible future iterations of Tropidoor could have additional/different capabilities and features.

To summarize, the presence of software like Tropidoor on devices can lead to multiple system infections, serious privacy issues, financial losses, and identity theft.

Backdoor-type malware examples

We have written about thousands of malicious programs; Anubis, Betruger, and Squidoor are merely a couple of our newest articles on backdoors.

Malware is a term encompassing software with a wide variety of malicious capabilities. Programs classed as such can have a narrow or an incredibly broad application. Yet regardless of how malware operates – its presence on a system threatens device integrity and user safety. Therefore, all threats must be removed immediately upon detection.

How did Tropidoor infiltrate my computer?

The campaign spreading Tropidoor alongside BeaverTail originated from spam emails. These messages were disguised as recruitment offers from a social networking platform for developers called DEV Community (dev.to). The fake emails included a link to the BitBucket repository for a project containing malicious code – the downloader (though which Tropidoor operates) and BeaverTail.

Other distribution methods are not unlikely. For example, BeaverTail has been widely spread through spam emails using job offer lures. These campaigns targeted LinkedIn users based in different locales of the World, yet the bulk of the emails were geared toward users located in South Korea.

Phishing and social engineering are standard in malware distribution. Malicious programs are usually disguised as or bundled with ordinary software/media. Infectious files come in various formats, e.g., archives (ZIP, RAR, etc.), executables (.exe, .run, etc.), documents (Microsoft Office, Microsoft OneNote, PDF, etc.), JavaScript, and so on. Merely opening a virulent file can be enough to initiate the infection chain.

Generally, malware is distributed through malicious attachments or links in spam mail (e.g., emails, PMs/DMs, etc.), drive-by (stealthy/deceptive) downloads, online scams, malvertising, untrustworthy download sources (e.g., freeware and third-party sites, P2P sharing networks, etc.), pirated programs/media, illegal software activation tools ("cracks"), and fake updates.

Furthermore, some malicious programs can self-spread through local networks and removable storage devices (e.g., external hard drives, USB flash drives, etc.).

How to avoid installation of malware?

We highly recommend vigilance with incoming communications. Attachments or links found in suspicious/irrelevant messages must not be opened, as they can be virulent. It is important to exercise caution when browsing since the Internet is rife with deceptive and malicious content.

Another recommendation is to download only from official and verified channels. Additionally, programs must be activated and updated using legitimate functions/tools, as illegal activation tools ("cracks") and third-party updates can contain malware.

It is essential for device/user safety to have a reputable anti-virus installed and kept updated. Security software must be used to run regular system scans and to remove threats and issues. 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:

By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by RCS LT, the parent company of PCRisk.com.

Quick menu:

• What is Tropidoor?
• STEP 1. Manual removal of Tropidoor malware.
• STEP 2. Check if your computer is clean.

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:

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:

Download a program called Autoruns. This program shows auto-start applications, Registry, and file system locations:

Restart 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.

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.

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.

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

Extract the downloaded archive and run the Autoruns.exe file.

In 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.

Check 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".

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.

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 Tropidoor malware, should I format my storage device to get rid of it?

Malware removal rarely requires such drastic measures.

What are the biggest issues that Tropidoor malware can cause?

The dangers depend on the malware's functionalities and the cyber criminals' modus operandi. Tropidoor aims to open a "backdoor" into systems and cause further infections. The presence of such software on devices can lead to multiple system infections, serious privacy issues, financial losses, and identity theft.

What is the purpose of Tropidoor malware?

The most common motivation behind malware attacks is profit. However, malicious programs can also be used for the cyber criminals' amusement or to realize their personal grudges, process disruption (e.g., websites, services, etc.), hacktivism, and political/geopolitical motivations.

How did Tropidoor malware infiltrate my computer?

Tropidoor has been proliferated via spam emails promoting a malicious project on the BitBucket repository. Other distribution techniques are possible.

Generally, malware is spread through drive-by downloads, spam emails/messages, online scams, malvertising, pirated content, dubious download channels (e.g., freeware and free file-hosting websites, P2P sharing networks, etc.), illegal software activation tools ("cracks"), and fake updates. Some malicious programs can self-proliferate via local networks and removable storage devices.

Will Combo Cleaner protect me from malware?

Combo Cleaner is designed to scan computers and eliminate all kinds of threats. It can detect and remove practically all known malware infections. Note that performing a complete system scan is essential since high-end malicious programs tend to hide deep within systems.