Do not trust fake Zoom application installers

What is Zoom virus?

"Zoom virus" is a generic term used to define unwanted or malicious software proliferated under the guise of content relating to the Zoom application/services.

Zoom Video Communications is a legitimate conferencing service, providing a cloud-based communication platform that enables people to have audio and video conferences, online meetings and exchange messages via chat.

Due to Zoom's accessibility (cross-platform, basic plans available free, etc.) and the current social climate (Coronavirus/COVID-19 pandemic), cyber criminals have begun misusing the company/product name to further their malicious purposes.

As Zoom's user base has grown exponentially with the influx of remote workers/students, so has cyber crime targeting this service/app.

Zoom virus overview

During research, it has been observed that cyber criminals spread malicious content using fake Zoom app installers. The executable files of these rogue installers are often named with variations of "zoom-us-zoom_*******.exe" (the asterisks represent differing words and/or characters).

These executables typically launch the InstallCore installer, which is a Potentially Unwanted Application (PUA). InstallCore then installs an unwanted or malicious piece of software. The proliferated programs are varied, depending on the criminals' modus operandi and goals.

They might be adware, browser hijackers or other PUAs, as well as Trojans, ransomware, cryptominers or other malware. It has been noted that the name of the Zoom service/application was misused to proliferate Neshta information-stealing malware.

Additionally, there has been an increase of domains registered incorporating 'Zoom' within them (e.g. resembling the domain of the genuine website as closely as possible). They are usually disguised as the "official" Zoom site or as "trustworthy" third party sites, from which users can supposedly download the Zoom app (thereby, tricking them into downloading malicious content).

In fact, these web pages can also be used for phishing purposes. I.e., to steal users' personal information such as their registered Zoom accounts, names, emails, credit card and banking account details (e.g. as billing information for payable features), and so on.

Therefore, to ensure device integrity and user safety, use only official download sources. If you suspect that unwanted/malicious software has already infiltrated the system, use an antivirus suite to eliminate it immediately.

Online scams in general

Cyber criminals and scammers often incorporate legitimate products, platforms, services organizations, institutions, companies, etc. into their schemes in some fashion. This increases their success rate, as people are less likely to suspect something with which they are familiar.

The Zoom Video Communications software is by far not the only product/service included in scams. For example, Microsoft Teams and Google Classroom services have been similarly misused. These legitimate entities have no connection to these scams that misuse their names.

How did Zoom virus infiltrate my computer?

The "Zoom virus" has been proliferated via fake Zoom installation set-ups.

Rogue installers are often downloaded from untrusted download sources such as unofficial and free file-hosting websites, Peer-to-Peer sharing networks (BitTorrent, eMule, Gnutella, etc.) and other third party downloaders, however, such dubious download channels can offer malicious content under various guises.

Other common malware proliferation methods are through Trojans, spam campaigns, fake updaters and illegal activation ("cracking") tools. Trojans are malicious programs that have varied capabilities, which can include the capability to cause chain infections (i.e., download/installation of additional malware).

The term "spam campaign" defines a large scale operation, during which deceptive/scam emails are sent by the thousand. These messages have infectious files attached to them or alternatively contain download links of malicious content.

Infectious files come in a number of formats such as archive (RAR, ZIP, etc.) and executable (.exe, .run, etc.) files, Microsoft Office and PDF documents, JavaScript, etc.

When these files are executed, run or otherwise opened, the infection process starts. Rogue updaters infect systems by exploiting weaknesses of outdated software and/or simply by installing malware rather than the promised updates. "Cracking" tools can download/install malicious programs, rather than active the licensed product.

How to avoid installation of malware

You are strongly advised to use only official and verified download sources. It is also important to activate and update products with tools/functions provided by genuine developers. Illegal activation tools ("cracks") and third party updaters should be avoided, as they are commonly used to proliferate malware.

Suspicious and/irrelevant emails should not be opened, especially those with any attachments or links found in them, since this can result in high-risk infection. To protect device and user safety, it is paramount to have a reputable anti-virus/anti-spyware suite installed.

Furthermore, this software must be kept up to date, used to run regular system scans and to remove detected threats/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 another malicious installer:

Yet another deceptive Zoom installer which targets German users and bundles a variety of unwanted applications:

Detections of a fake Zoom installer (which distributes njRAT) in VirusTotal:

Detections of a fake Zoom installer (which distributes cryptominers) in VirusTotal:

Screenshot of the legitimate and official Zoom website:

Screenshot of a malicious website used to promote a fake Zoom installer setup:

Update 21 May 2020 - Recently, two malicious Zoom installers have been detected. One is designed to inject a 'backdoor virus', which provides cyber criminals with remote access to the infected device. Once the backdoor is injected, the genuine Zoom installer will be opened so that users do not become suspicious.

The other malicious installer is designed to spread the Devil Shadow botnet. Devil Shadow not only controls the system, but can also spy the user by taking screenshots, using the webcam and so on. You can find more technical details in the Trend Micro's article.

Screenshot of yet another deceptive Zoom download website. The setup installs a modified Zoom application which connects to a remote server and downloads/installs either IcedID or Cobalt Strike trojans:

Detections of fake Zoom installer used to inject Redline Stealer:

How to remove malware manually?

Most trojan infections can be removed by running a full system scan with Combo Cleaner. The full manual procedure below is for cases where automatic removal failed, where you want to verify a scan caught everything, or where the threat has multiple persistence points.

Tools you'll need

Combo Cleaner Antivirus 7-days free trial

Recommended primary scanner. VB100 certified. The 7-day free trial is available.

Microsoft Defender Offline Free · built-in

Built into Windows. Boots to a clean environment to catch rootkits.

Process Explorer Free

From Microsoft Sysinternals. Better than Task Manager - shows full paths and signatures.

Autoruns Free

From Microsoft Sysinternals. Lists every place malware can persist on your system.

Microsoft Safety Scanner (MSERT) Free

Official Microsoft on-demand scanner. Always-current signatures - expires every 10 days.

Phase 1~ 5 min

Contain - limit the damage

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1

Disconnect from the network

30 secNo tool needed

Unplug your Ethernet cable and turn off Wi-Fi. If you're on a laptop, the airplane-mode key works fastest.

Why this matters

Many trojans exfiltrate data - saved browser passwords, banking sessions, screenshots - and accept remote commands. Cutting the network stops both immediately. Keep it disconnected until Phase 4.

2

Boot into Safe Mode with Networking

3 min

Safe Mode loads a minimal set of drivers and stops most malware from auto-running. "With Networking" lets you download tools - re-enable Wi-Fi only after you've booted in.

Windows 11

Open Settings → System → Recovery. Click Restart now next to Advanced startup.

Your computer will restart into the "Choose an option" menu. Click Troubleshoot → Advanced options → Startup Settings → Restart. After the second reboot, press 5 or F5.

Windows 10

Click the Windows logo, hold Shift, click the Power icon and choose Restart. In the Choose an option screen, click Troubleshoot → Advanced options → Startup Settings → Restart. Press F5.

Windows 8

Go to the Start Screen, type Advanced, select Settings → Advanced startup options → Restart now → Troubleshoot → Advanced options → Startup settings → Restart → F5.

Note: Windows 8 reached end-of-life in January 2023 - running on it puts you at much higher risk of reinfection.

Windows 7

Click Start → Shut Down → Restart → OK. As the system boots, press F8 repeatedly until the Windows Advanced Options menu appears, then choose Safe Mode with Networking.

Note: Windows 7 reached end-of-life in January 2020 - running on it puts you at much higher risk of reinfection.

Phase 2~ 15 min

Identify - find what's hiding

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3

Inspect running processes with Process Explorer

Tool: Process Explorer5 min

Download Process Explorer from Microsoft Sysinternals. Run it as Administrator. Click Options → Verify Image Signatures and View → Lower Pane View → DLLs.

Sort by "Verified Signer." Anything unsigned running from %AppData%, %LocalAppData%, %Temp%, or %ProgramData% is suspicious. Right-click → Properties to see the full image path. Right-click → "Search Online" to look up unfamiliar process names.

Why not just Task Manager

Task Manager hides full file paths, doesn't show digital signatures, and groups processes in ways that make malware easy to miss. Process Explorer is the same tool Microsoft engineers use.

4

Map every persistence point with Autoruns

Tool: Autoruns 14.x10 min

Download Autoruns. Right-click Autoruns.exe and choose Run as administrator - without elevation, Autoruns can't inspect protected registry hives.

In the menu, open Options → Hide Microsoft Entries and Options → Hide Empty Locations, then click Refresh.

Modern trojans don't just live in startup. Walk through these tabs and look for unsigned or unfamiliar entries:

• Logon - classic Run/RunOnce keys
• Scheduled Tasks - frequent hiding spot, especially tasks with PowerShell, MSHTA, or rundll32 actions
• Services - unsigned services in non-Microsoft folders
• WMI - Event Subscriptions are a stealthy persistence mechanism (MITRE T1546.003)
• Image Hijacks - Image File Execution Options "Debugger" abuse
• AppInit - DLLs loaded into every GUI process
• Browser plug-ins - unsigned add-ons across all installed browsers

Pro tip

Right-click any suspicious entry → "Jump to Image" to see the actual file. Right-click → "Search Online" opens VirusTotal for the file hash. Don't delete yet - just write down the file paths and entry names. We'll remove them after the scans.

5

Check the hosts file and DNS settings

3 minBuilt into Windows

Trojans often redirect bank, antivirus, and update domains to attacker-controlled servers by editing the hosts file or DNS settings.

Hosts file: Open Notepad as Administrator and open C:\Windows\System32\drivers\etc\hosts. Legitimate entries are commented with #. Any uncommented IP-to-domain mapping is suspicious - especially redirects for microsoft.com, windowsupdate, or your bank.

DNS settings: Open Command Prompt as Administrator and run ipconfig /all. Confirm your DNS servers point to your ISP, your router, or a known public resolver (Cloudflare 1.1.1.1, Google 8.8.8.8). Then open Settings → Network & internet → [your adapter] → DNS server assignment and verify both DNS and DNS over HTTPS (DoH) settings haven't been hijacked.

Why this matters

A clean PC with hijacked DNS is still a compromised PC. You'll think you're at chase.com and you'll be at the attacker's clone.

Phase 3~ 60-90 min

Remove - three scans, one cleanup

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No single antivirus catches everything. The order below is intentional: offline scan first (catches rootkits before Windows fully loads), then on-demand scanners on the running system, then manual cleanup of anything they missed.

6

Run Microsoft Defender Offline

Tool: Built into Windows15 min

Reboot to normal Windows. Open Windows Security → Virus & threat protection → Scan options. Select Microsoft Defender Antivirus (offline scan) and click Scan now. Your computer will restart into a stripped-down environment and scan before the full operating system loads.

Why this comes first

Rootkits and bootkits hide from any scanner running on the same Windows session that's already infected. A pre-boot offline scan sees the disk before the malware can hide itself.

Recommended antivirus

Combo Cleaner

VB100 certified. Includes anti-trojan, registry/persistence scanning, anti-spyware in one pass. The 7-day free trial is available.

Download Combo Cleaner

7

Run Combo Cleaner full system scan

Tool: Combo Cleaner20-40 min

Install Combo Cleaner and run a full system scan (not the quick scan). Let it complete fully, review the detected threats, and apply the recommended actions. Combo Cleaner will quarantine known trojans and registry persistence.

8

Run Microsoft Safety Scanner as a second-opinion scan

Tool: Microsoft Safety Scanner15 min

Download Microsoft Safety Scanner (MSERT.exe), Microsoft's free on-demand tool. The binary expires every 10 days, which means every download has the latest signatures. Run a full scan after Combo Cleaner to catch anything one engine alone might miss.

Why a second scan

Different scanning engines catch different threats. Running an additional Microsoft scan after Combo Cleaner is the single most underused verification step in malware removal.

9

Manually remove anything still listed in Autoruns

Tool: Autoruns10 min

Reopen Autoruns. Anything you flagged in Step 4 that's still present hasn't been caught by the automated scans. For each remaining suspicious entry: right-click → Delete in Autoruns (this removes the persistence registration), then navigate to the file path and delete the actual file. Empty the Recycle Bin.

Important

Some malware files reappear after deletion because something else on the system recreates them. If you delete a file and it returns within minutes, you have a remaining persistence point that Autoruns didn't show - usually a service or scheduled task running under SYSTEM. Re-run the scans from Steps 6-8 or proceed to a clean install (see end of guide).

Phase 4~ 15 min

Recover - restore browsers and security

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10

Reset browsers and clear notification permissions

5 min

Trojans and adware frequently hijack browsers - change the default search engine, install rogue extensions, or grant themselves notification permissions to keep displaying scam pop-ups even after the malware is gone.

• Chrome: visit chrome://settings/reset and click "Restore settings to their original defaults." Then visit chrome://settings/content/notifications and remove any unfamiliar sites.
• Edge: visit edge://settings/reset. Then check edge://settings/content/notifications.
• Firefox: open about:support and click Refresh Firefox (Firefox uses "Refresh," not "Reset"). Then check Settings → Privacy & Security → Permissions → Notifications.

Review installed extensions in each browser and remove anything you don't recognize, especially extensions you didn't install yourself.

11

Re-enable Defender, Tamper Protection, and update everything

10 min

Many trojans disable security software. Open Windows Security → Virus & threat protection → Manage settings and confirm Real-time protection, Cloud-delivered protection, and Tamper Protection are all turned on. Tamper Protection prevents malware from disabling Defender silently.

Then run Windows Update (Settings → Windows Update → Check for updates) and update your browsers and applications. The infection vector that let the trojan in originally usually involves outdated software.

Phase 5~ 15 min + 7 days

Verify & secure

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12

Change passwords from a clean device

20 min⚠ Critical

If the trojan was an info-stealer (Lumma, RedLine, Vidar, and similar are extremely common), assume every password saved in your browser is compromised. Change them from a different, known-clean device - your phone is fine if it's not infected.

Recommended order:

1. Primary email first - it's the recovery hub for everything else
2. Banking and financial accounts
3. Password manager master password (if you use one)
4. Social media, shopping, and remaining accounts

Where available, enable phishing-resistant multi-factor authentication (passkeys / FIDO2 hardware keys / authenticator apps) - SMS-based MFA is bypassable by sophisticated attackers.

13

Verify the clean and monitor for 7 days

5 min + 1 week monitoring

Reconnect to the network and run one final full scan with Combo Cleaner. Open Task Manager (Ctrl + Shift + Esc) and switch to the Startup apps tab - confirm nothing suspicious has reappeared.

Over the next 7 days, watch for symptom recurrence: unexpected high CPU usage, unknown processes returning, browser redirects, or pop-ups. If anything returns, you missed a persistence point and the procedure needs to be repeated - or you may have a deeper compromise that requires a clean install.

When to clean install Windows instead

Manual removal isn't always the right answer. Reinstalling Windows from scratch is the only way to be 100% certain when:

• The malware reappears after every removal attempt
• A bootkit or UEFI rootkit was detected (this class of threat sits below the operating system and survives a normal Windows reinstall)
• A confirmed credential-theft trojan ran with administrator privileges (Lumma, RedLine, Vidar) - the system likely has multiple unknown payloads
• The PC is used for online banking, business email, or anything where partial doubt isn't acceptable

A clean install is a 30-60 minute process: Windows 11 reinstall via Settings → System → Recovery → Reset this PC → Remove everything → Cloud download. Back up documents to external storage first, scan the backup with Combo Cleaner before restoring it, and reinstall applications fresh - never restore them from a backup of the infected system.

Important: Manual removal requires advanced computer skills. If you're not confident identifying system files from malicious files, run an automated scan with Combo Cleaner and Windows Defender and stop there - that path catches the vast majority of consumer trojans without the risk of breaking Windows by deleting the wrong file.

Frequently Asked Questions (FAQ)

What is "Zoom virus"?

"Zoom virus" refers to rogue, deceptive, and malicious content presented as the Zoom application/services. This term encompasses fake Zoom installers containing adware, browser hijackers, PUAs, trojans, ransomware, cryptominers, or other malware. "Zoom virus" also includes fraudulent websites relating to this software/services, which operate as phishing scams or proliferate malware.

What are the biggest issues that "Zoom virus" can cause?

The threats posed by any type of content depend on its purpose. For example, phishing scams aim to acquire sensitive information, which can then be abused or sold to third-parties. And what dangers a malware infection poses - depend on the program's abilities and the cyber criminals' modus operandi. Generally, system infections can result in severe privacy issues, data loss, hardware damage, financial losses, and identity theft.

What is the purpose of "Zoom virus"?

Deceptive and malicious content, such as "Zoom virus", is most commonly used to generate revenue. However, how the cyber criminals profit can vary; they may do so by obtaining funds fraudulently (e.g., promoting fake in-app purchases, services, products, etc.), abusing or selling private data, proliferating malware, and so forth.

I suspect that my private data has been compromised by "Zoom virus", what should I do?

If you believe that your log-in credentials have been extracted through a "Zoom virus", we advise you to immediately change the passwords of all potentially exposed accounts and inform their official support. And if the data at risk is of a different personal nature (e.g., ID card details, credit card numbers, etc.) - contact the appropriate authorities without delay.

Will Combo Cleaner protect me from "Zoom virus"?

Yes, Combo Cleaner is designed to detect and eliminate threats. It is capable of removing adware, browser hijackers, PUAs, and most of the known malware infections. Additionally, when a rogue, deceptive, or malicious site is entered - Combo Cleaner can prevent further access to it. Note that sophisticated malware tends to hide deep within systems - therefore, running a full system scan is paramount for its detection.

It is pertinent to mention that manual program removal (performed without the aid of security software) might be ineffective. In some instances, even after the undesirable software has been manually removed - various leftover files remain within the system. These remnants may continue to run and cause problems. Hence, it is crucial to eliminate unwanted software thoroughly.