How to eliminate Winos4.0 malware from your device

What kind of malware is Winos4.0?

Winos4.0 (also known as WinosStager) is a sophisticated malware framework with backdoor, loader, and stealer capabilities. This high-risk malware has been used in multiple campaigns, which have been particularly active in Asia. Winos4.0 has been distributed through fake RustDesk websites.

Winos4.0 malware overview

Winos4.0 infiltrates systems through a multi-stage chain. In recent campaigns, it originated from malicious webpages imitating the official RustDesk remote access software website. The downloaded installation setup contains the legitimate RustDesk executable and the second-stage loader. The former is not trojanized and is fully operational, thus it serves as a perfect decoy and does not raise victims' suspicion.

The loader preps the system for the final payload. In the final stage, Winos4.0 is deployed exclusively in-memory. This is but one of the techniques that this malicious program employs to avoid detection, as traditional security tools do not detect file-less malware. It also checks for the presence of debugging tools as an anti-analysis measure. Winos4.0 collects geolocation data, which could be used to target or avoid specific regions.

As a backdoor, this program seeks to maintain persistent and stealthy access to victims' devices. It continuously monitors user activity. The malware's data-stealing capabilities include taking screenshots, recording keystrokes (keylogging), and stealing various credentials.

Generally, cyber criminals seek to obtain passwords and other data associated with cloud storage, FTP (File Transfer Protocol) clients, VPNs (Virtual Private Networks), email clients, messengers, entertainment-related software/accounts, e-commerce, online banking, cryptocurrency wallets, and so on.

Additionally, Winos4.0 can cause chain infections. While in theory, loader-type malware can cause just about any infection (e.g., trojan, ransomware, cryptominer, etc.), in practice – these programs tend to operate within certain limitations or specifications.

To summarize, the presence of malicious software like Winos4.0 on devices can result in multiple system infections, data loss, severe privacy issues, financial losses, and identity theft.

Backdoor-type malware examples

YiBackdoor, Tropidoor, and Anubis are just a couple of our latest articles on backdoors. Programs of this kind are designed to open a "backdoor" for further infection into targeted systems. Some backdoors can carry out the infection, i.e., download/install additional malware.

Keep in mind that regardless of how malicious software operates – its presence on a system threatens device integrity and user safety. Therefore, all threats must be eliminated immediately upon detection.

How did Winos4.0 infiltrate my computer?

Winos4.0 has been observed being distributed through fake RustDesk download webpages. The known page is a close visual imitation of the remote access software's official website. The malicious webpage was promoted through a form of malvertising, in which it was inserted as the top result in search engine results.

Note that it could also be endorsed using different techniques, such as other types of malicious advertising, sites using rogue advertising networks, spam (e.g., browser notifications, emails, PMs/DMs, social media/ forum posts, etc.), typosquatting (misspelled URLs), and adware.

The fraudulent page provided an installer containing a legitimate RustDesk executable bundled with a loader intended to install Winos4.0.

Other distribution methods are possible. Phishing and social engineering tactics are standard in malware proliferation. Malicious software is usually disguised as or bundled with legitimate/ordinary content.

Malware is primarily distributed via malvertising, online scams, malicious attachments or links in spam emails/messages, drive-by (stealthy/deceptive) downloads, dubious download channels (e.g., freeware and free file-hosting websites, 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.).

Infectious files come in different formats, such as executables (EXE, RUN, etc.), archives (ZIP, RAR, 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.

How to avoid installation of malware?

We highly recommend downloading only from official and verified sources. All programs must be activated and updated using functions/tools provided by legitimate developers, as those acquired from third-parties can contain malware.

Another recommendation is to be vigilant when browsing, as the Internet is full of deceptive and dangerous content. Incoming emails and other messages must be approached with care. Attachments or links found in dubious/irrelevant mail must not be opened, as they can be malicious.

We strongly advise having a reputable antivirus installed and kept updated. Security software must be used to run regular system scans and to remove detected 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.

Screenshot of a fake RustDesk website distributing Winos4.0 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 Winos4.0?
• STEP 1. Manual removal of Winos4.0 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 Winos4.0 malware, should I format my storage device to get rid of it?

Most likely, no, as malware removal rarely requires formatting.

What are the biggest issues that Winos4.0 malware can cause?

The dangers posed by an infection depend on the malware's abilities and the cyber criminals' goals. Winos4.0 is a multifunctional malware capable of causing chain infections, spying on victims, and extracting private data. Hence, its presence can lead to multiple system infections, serious privacy issues, financial losses, and identity theft.

What is the purpose of Winos4.0 malware?

Malware is primarily used for financial gain. However, infections can also be motivated by the attackers' amusement or personal grudges, process disruption (e.g., websites, services, etc.), hacktivism, and political/geopolitical reasons.

How did Winos4.0 malware infiltrate my computer?

Winos4.0 has been spread through fake RustDesk sites. Other proliferation techniques are not unlikely. In general, malware is distributed through drive-by downloads, suspicious download channels (e.g., freeware and third-party websites, P2P sharing networks, etc.), spam mail, malvertising, online scams, illegal software activation tools ("cracks"), pirated content, and fake updates. Some malicious programs can self-spread via local networks and removable storage devices.

Will Combo Cleaner protect me from malware?

Yes, Combo Cleaner is capable of detecting and removing most of the known malware infections. It must be emphasized that running a full system scan is critical since high-end malicious software usually hides deep within systems.