How to eliminate Fickle stealer-type malware from the operating system

What kind of malware is Fickle?

Fickle is a stealer-type malware written in the Rust programming language. This malicious program is designed to steal vulnerable information from devices. Fickle has bee around since at least the spring of 2024. This stealer is highly flexible and can infiltrates system in several different multi-stage infection chains.

Fickle malware overview

As mentioned in the introduction, Fickle can infiltrate devices via different processes. The stealer has anti-analysis capabilities, such as anti-debugging, VM (Virtual Machine) and sandbox detection, as well as checking for terms/names associated with malware analysis and analysts.

Fickle gathers extensive information about the infected machine, such as device name, hardware details (e.g., CPU, GPU, etc.), operating system version and architecture, language settings, geolocation data (e.g., IP address, country, city, etc.), username, installed programs, running processes, and so on.

The stealer can exfiltrate information from a variety of applications. It can acquire data from Chromium and Gecko based browsers. From browsers, cyber criminals primarily seek browsing histories, Internet cookies, log-in credentials (usernames/passwords), personally identifiable details, credit card numbers, etc.

Furthermore, Fickle seeks information from messengers, cryptocurrency wallets, password managers, remote access programs, FTP (File Transfer Protocol) clients, and gaming-related software (extensive list below).

The program can download files from devices (targeted format list below). Additionally, Fickle can take screenshots. It can also terminate itself, and before deletion, the malware can display a fake error message.

It is noteworthy that malicious software developers commonly improve upon their programs and methodologies. What is more, evidence suggests that Fickle is in active development and use. Therefore, potential future iterations of this stealer can have additional/different functionalities and features.

To summarize, the presence of software like Fickle on devices can lead to severe privacy issues, financial losses, and identity theft.

Stealer-type malware examples

We have investigated countless malware samples; Kematian, KoiStealer, Waltuhium, Vert, and Braodo are merely some of our newest articles on stealers. Information-targeting malware can seek specific details or a broad range of data. These abilities (i.e., data extraction) are common for various types of malware.

Yet regardless of whether a malicious program steals information or operates in a different manner, its presence on a system threatens device and user safety. Hence, all threats must be eliminated immediately upon detection.

How did Fickle infiltrate my computer?

Fickle has been observed originating from different format files, several Microsoft Word documents, executables, and LNK (Windows Shortcut) files. Four primary delivery methods were noted in use for this stealer – VBA dropper, VBA downloader, link downloader, and executable downloader.

Regardless of the technique, they typically rely on PowerShell scripts to lay the groundwork for the infection. Fickle arrives onto systems in multi-stage chains that can involve batch and data files, executables, embedded URLs, etc. However, how the originator files are distributed is currently unknown.

Generally, cyber criminals proliferate malware by using phishing and social engineering tactics. Infectious files come in various formats, e.g., documents (Microsoft Office, Microsoft OneNote, PDF, etc.), executables (.exe, .run, etc.), archives (ZIP, RAR, etc.), JavaScript, and so on.

The most widespread malware distribution techniques include: drive-by (stealthy/deceptive) downloads, malicious attachments/links in spam mail (e.g., emails, PMs/DMs, SMSes, etc.), online scams, malvertising, dubious download channels (e.g., freeware and third-party sites, P2P sharing networks, etc.), illegal software activation tools ("cracks"), and fake updates.

Some malicious programs can even self-spread 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 downloading only from official and verified sources. All programs must be activated and updated using legitimate functions/tools, as those obtained from third-parties may contain malware.

Another recommendation is to be careful while browsing, as fraudulent and dangerous online content usually appears genuine and harmless. Incoming emails and other messages must be approached with caution. Attachments or links in suspicious/irrelevant mail must not be opened, as they can be malicious.

It is essential for device/user safety to have a dependable 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.

Partial list of software targeted by Fickle stealer;

Targeted browsers:

• Google Chrome
• Microsoft Edge
• Opera
• Opera GX
• 7 Star
• Amigo
• Brave
• CentBrowser
• Epic
• Iridium
• Kometa
• Orbitum
• Sputnik
• Torch
• Vivaldi
• Yandex

Targeted cryptocurrency wallets and crypto-related extensions:
Armory, Atomic, Auro, BinanceChain, BitClip, Byone, ByteCoin, Clover, Coin98, Coinbase, Coinomi, Cyano, Cyano Wallet Pro, Electrum, EQUAL, Eternl, Ethereum, Exodus, Guarda, Hycon Lite Client, ICONex, iWallet, Jaxx, Keplr, KHC, LeafWallet, Liquality, Maiar DeFi, Math, MetaMask, MEW CX, Nabox, Nami, Nash, NeoLine, Nifty, OneKey, Polymesh, Ronin, Saturn, Sollet, SteemKeychain, Terra Station, TezBox, TronLink, UniSat, Wombat, Yoroi, ZCash, ZilPay, etc.

Targeted password managers and authentication software:

• 1Password
• Authenticator
• Avira Password Manager
• Bitwarden
• BrowserPass
• CommonKey
• Dashlane
• EOS Authenticator
• KeePassXC
• Keeper
• LastPass
• MYKI
• NordPass
• Norton Password Manager
• RoboForm
• Splikity
• Trezor Password Manager
• Zoho Vault

Targeted messaging software:

• Discord
• Element
• ICQ
• Pidgin
• Signal
• Skype
• Telegram
• Tox

Targeted miscellaneous software:

• Anydesk
• FileZilla
• Steam
• Ubisoft

Targeted file extensions:
.doc, .docx, .kdbx, .odp, .odt, .pdf, .ppt, .pptx, .txt, wallet.dat, .xls, .xlsx

Update February 28, 2025 – Fickle stealer has been used in campaigns carried out by threat actors tracked as EncryptHub (aka Larva-208). This group has been active since the summer of 2024 and has attacked over six hundred organizations worldwide.

These campaigns employed phishing, social engineering, and tech support scam tactics. Another group – Larva-148 – is responsible for the phishing and associated infrastructure.

After successfully breaching corporate networks, EncryptHub introduces stealers like Fickle, Rhadamanthys, or Stealc. The infection can then culminate in a ransomware infection. The known malware used were linked to groups behind the BlackSuit and RansomHub ransomware-type programs.

More information on these campaigns can be found in an article by Bill Toulas on BleepingComputer.

Update April 1, 2025 – In a recent interview, the developer stated that Fickle Stealer was inspired by Kematian. The developer noted that Fickle Stealer is optimized to bypass corporate security where other stealers fail and can disable defenses for further infections. Alternative delivery methods are also being tested to improve stealth.

Update July 21, 2025 – threat actors tracked as EncryptHub (Larva-208) continue using Fickle stealer in their operations. New sophisticated social engineering campaigns spreading this malware have emerged. The latest targets are Web3 developers, who are contacted with bogus job offers or requests to review their portfolios.

Several campaigns seeking these victims have been observed. The steps differ depending on the platform through which victims are initially contacted.

Targeted individuals can be sent malicious links directly if the platform allows it. The lure is a meeting link to a fake AI (Artificial Intelligence) Workspace application ("Norlax AI"; possibly other names), accessible only with a code sent to the victim. Eventually, users encounter an error on the page stating that their audio drivers are missing/outdated. The infection chain is triggered once victims download and install the malware, which is disguised as the Realtek HD Audio Driver.

Alternatively, if victims are contacted via a platform like Remote3, which warns users against clicking links outside of those associated with legitimate conferencing software like Zoom or Google Meet, the cyber criminals first set an online meeting using said programs. In the chat windows therein, they share malicious links to the fake AI Workspace application.

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)

My computer is infected with Fickle 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 Fickle malware can cause?

The dangers associated with an infection depend on the malware's capabilities and the cyber criminals' modus operandi. Fickle is designed to steal sensitive information from devices. Typically, infections of this kind can lead to severe privacy issues, financial losses, and identity theft.

What is the purpose of Fickle malware?

Most malware infections are motivated by profit. However, cyber criminals can also use malicious software to amuse themselves, carry out personal vendettas, disrupt processes (e.g., websites, services, companies, organizations, etc.), and launch politically/geopolitically motivated attacks.

How did Fickle malware infiltrate my computer?

Malware is primarily distributed via drive-by downloads, spam mail, online scams, malvertising, untrustworthy download channels (e.g., freeware and free file-hosting sites, P2P sharing networks, etc.), fake updaters, and illegal software activation ("cracking") tools. Furthermore, some malicious programs can self-proliferate through local networks and removable storage devices.

Will Combo Cleaner protect me from malware?

Yes, Combo Cleaner can scan devices and eliminate all kinds of threats. It can remove most of the known malware infections. It must be stressed that performing a full system scan is crucial since sophisticated malicious programs usually hide deep within systems.