Zephyr Miner Malware

What kind of malware is Zephyr Miner?

Zephyr Miner is a piece of malicious software classified as a cryptocurrency miner. This malware is designed to mine (i.e., generate) the Zephyr (ZEPH) cryptocurrency for the attackers. Zephyr Miner is a sophisticated cryptominer that exhibits anti-detection and persistence-ensuring capabilities.

Zephyr Miner malware detections on VirusTotal

Zephyr Miner malware overview

Zephyr Miner has been observed infiltrating devices using four distinct methods. Each of these different processes is initiated by either a batch file, VBScript (Visual Basic Script) file, PowerShell script, or a Portable Executable file.

Following successful infiltration, this cryptocurrency miner takes action to prevent its detection. This activity includes adding itself to the exclusion list of the Microsoft Defender Antivirus. It also deleted artifacts left over during the infection chain. Additionally, Zephyr Miner uses persistence-ensuring mechanisms, such as setting itself as a scheduled task.

After connecting to its mining pool, Zephyr Miner begins mining the Zephyr (ZEPH) cryptocurrency. This process involves using system resources (like processors [CPUs] and graphics cards [GPUs]) to solve mathematical problems. Zephyr Miner sets the maximum CPU usage to 50%.

The presence of a cryptominer on a device can result in a variety of issues, as the abuse of system resources leads to additional strain on the system, and it may begin "freezing" or crashing. Hence, the computer's performance can be significantly diminished.

What is more, should a miner use a high percentage of system resources, this can produce an excessive amount of heat. Under certain circumstances (such as high room temperatures), the hardware may be damaged. Therefore, cryptocurrency miners can cause data loss, potential privacy issues, and financial losses.

Threat Summary:
Name	Zephyr cryptocurrency miner
Threat Type	Trojan, cryptocurrency miner, cryptominer, miner.
Detection Names	Avast (Win64:Evo-gen [Trj]), Combo Cleaner (Gen:Variant.Ser.Lazy.7003), ESET-NOD32 (A Variant Of Win64/Agent.EVY), Kaspersky (Trojan.Win32.SelfDel.iuvs), Microsoft (Trojan:Win64/Lazy.GTL!MTB), Full List Of Detections (VirusTotal)
Symptoms	While trojans are designed to stealthily infiltrate the victim's computer (thus no particular symptoms are clearly visible), miners abuse system resources, which can diminish device performance.
Distribution methods	Infected email attachments, malicious online advertisements, social engineering, software 'cracks'.
Damage	Victim's computer added to a botnet, diminished system performance, hardware damage, potential privacy issues, financial losses.
Malware Removal (Windows)	To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. Download Combo Cleaner 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.

Cryptocurrency-mining malware examples

We have written about numerous malicious programs; Grand Explorer, SilentCryptoMiner, Altruistics, Kratos Silent Miner, and Sapphire are merely some of our articles on miners.

Malware is a broad term that covers software with a wide variety of capabilities. However, regardless of how a malicious program operates – its presence on a system threatens device integrity and user safety. Therefore, all threats must be eliminated immediately upon detection.

How did Zephyr Miner infiltrate my computer?

The methods used to proliferate Zephyr Miner are currently unknown. Generally, malware is spread by relying on phishing and social engineering techniques. It is usually disguised as or bundled with ordinary programs/media. Virulent files can be executables (.exe, .run, etc.), archives (ZIP, RAR, etc.), documents (PDF, Microsoft Office, Microsoft OneNote, etc.), JavaScript, and so on. Merely opening such a file can be enough to initiate the infection chain.

The most common malware distribution methods include: backdoor/loader-type trojans, drive-by (stealthy/deceptive) downloads, malicious attachments or links in spam emails/messages, untrustworthy download sources (e.g., freeware and third-party websites, P2P sharing networks, etc.), pirated content, online scams, fake updaters, and illegal software activation ("cracking") tools.

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

How to avoid installation of malware?

We strongly recommend being careful while browsing since the Internet is rife with deceptive and malicious content. Incoming emails and other messages must be approached with caution. Attachments or links present in dubious/irrelevant mail must not be opened, as they can be harmful or infectious.

Additionally, all downloads must be performed from official and verified channels. Another recommendation is to activate and update software using functions/tools provided by genuine developers, as those obtained from third-parties can contain malware.

It is paramount for device/user safety to have a reputable anti-virus installed and kept up-to-date. Security programs must be used to run regular system scans and to remove detected threats. 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.

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

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.

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.

Run Windows 11 in Safe Mode with Networking

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

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.

Process Explorer showing a suspicious unsigned process running from %AppData%

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.

Autoruns 14.x with Hide Microsoft Entries enabled showing the Logon and Scheduled Tasks tabs

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

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.

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

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.

Combo Cleaner full scan results showing detected threats

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.

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

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.

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

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:

Primary email first - it's the recovery hub for everything else
Banking and financial accounts
Password manager master password (if you use one)
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.

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.

Verifying malware removal in the Windows 11 Task Manager Startup apps tab

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)

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

Malware removal seldom requires formatting.

What are the biggest issues that Zephyr Miner malware can cause?

The dangers posed by an infection depend on the malicious program's capabilities and the cyber criminals' goals. Zephyr Miner is a miner – a type of malware designed to generate cryptocurrency by abusing system resources. Infections of this kind can lead to diminished system performance, data loss, potential privacy issues, hardware damage, and financial losses.

What is the purpose of Zephyr Miner malware?

Profit is the most common motivation behind malware attacks, and based on Zephyr Miner's abilities – it is not an exception. However, cyber criminals can use malicious software for other reasons, such as to amuse themselves, carry out personal vendettas, disrupt processes (e.g., sites, services, companies, etc.), engage in hacktivism, and launch politically/geopolitically motivated attacks.

How did Zephyr Miner malware infiltrate my computer?

Malware is predominantly spread via trojans, drive-by downloads, spam mail, online scams, suspicious download channels (e.g., unofficial and free file-hosting sites, Peer-to-Peer sharing networks, etc.), pirated content, fake updaters, and illegal software activation ("cracking") tools. Some malicious programs can even self-spread through local networks and removable storage devices.

Will Combo Cleaner protect me from malware?

Combo Cleaner can detect and eliminate practically all known malware infections. Note that high-end malicious software typically hides deep within systems – therefore, performing a complete system scan is crucial.

How to eliminate Zephyr miner malware from the operating system