How to remove TCLBanker malware from the operating system

What kind of malware is TCLBanker?

TCLBanker is a banking trojan that targets users in Brazil by silently monitoring their browsers and activating when they visit any of 59 monitored banking, fintech, or cryptocurrency websites. Once triggered, it overlays a convincing fake interface on top of the victim's real banking session to harvest login credentials while allowing operators to remotely observe and manipulate the infected machine.

According to research by Elastic Security Labs, TCLBanker is assessed to be a significant update to earlier Brazilian banking trojan families known as Maverick and SORVEPOTEL. The campaign is tracked internally as REF3076. At the time of analysis, several components were still under development, suggesting the malware was in an early operational stage.

The malware arrives disguised as a legitimate Logitech software installer and, once active, spreads further by hijacking the infected user's own WhatsApp and Outlook accounts to send phishing messages to their contacts.

TCLBanker overview

TCLBanker's core banking component, internally labelled Tcl.Agent, uses UI Automation to continuously watch the address bar of popular web browsers. The moment a victim navigates to one of 59 targeted Brazilian banking, fintech, or cryptocurrency domains, the malware establishes a WebSocket connection to its command-and-control server and notifies the operator that a victim is active on a banking site.

With a session open, the attacker can deploy a WPF-based full-screen overlay that completely covers the victim's browser window. These overlays can show convincing fake banking login pages, fake Windows Update progress screens, and voice-phishing (vishing) prompts - all designed to trick the victim into handing over credentials or authorizing a fraudulent transaction without realizing the interface is fake.

Remote access and control capabilities

Beyond the overlay framework, TCLBanker gives operators a range of remote tools during an active session. They can take screenshots, stream the victim's screen live, record keystrokes via a built-in keylogger, intercept clipboard contents, and execute shell commands directly on the infected machine.

To stop victims from closing the overlay or switching windows, TCLBanker actively blocks several keyboard shortcuts - including Tab, Escape, Alt+F4, PrintScreen, and the Windows key - and kills Task Manager every 500 milliseconds if the victim tries to open it. Overlays are also hidden from screen-capture tools using the WDA_EXCLUDEFROMCAPTURE flag, so they cannot be easily documented or noticed through recording software.

Worm modules: self-spreading via WhatsApp and Outlook

TCLBanker includes two worm components tracked as Tcl.WppBot. The first hijacks the victim's authenticated WhatsApp Web browser session to silently send phishing messages to all of their contacts. The second uses COM automation to send phishing emails directly through the victim's own Outlook account.

Because these messages arrive from a real, trusted account rather than an unknown sender, recipients are far more likely to open the link or attachment and run the installer themselves. Each newly infected machine then becomes another distribution point, allowing the malware to spread outward through social networks without the attacker needing to operate additional infrastructure.

Targeted applications

TCLBanker monitors browser navigation in Chrome, Firefox, Microsoft Edge, Brave, Opera, and Vivaldi. It watches for visits to 59 Brazilian banking, fintech, and cryptocurrency domains - a list that includes major retail banks, digital payment platforms, and cryptocurrency exchanges operating in Brazil.

The worm modules specifically target WhatsApp Web (accessed through any of the monitored browsers) and Microsoft Outlook for self-spreading. The malware's geofencing confirms Brazilian Portuguese locale, regional identifiers, and keyboard layout before activating, so it exits silently on machines outside its intended target profile.

Persistence and defense evasion

To survive reboots, TCLBanker copies its application directory to %LocalAppData%\LogiAI and registers a hidden scheduled task named RuntimeOptimizeService with a logon trigger, so it restarts automatically each time the user signs in.

The initial infection relies on DLL sideloading: a legitimate Logitech executable loads a malicious screen_retriever_plugin.dll placed alongside it, which decrypts and executes the main payload in memory without writing obvious files to disk. The payload decryption itself is environment-gated - it fails silently if the malware detects it is running in a sandbox, automated analysis environment, or virtualization platform.

Before activating, TCLBanker runs at least six anti-debugging checks, looks for virtualization software (VMware, VirtualBox, KVM, Xen, Parallels, QEMU), scans for sandbox-associated usernames, verifies the machine has at least 64 GB of disk space, 2 GB of RAM, and two CPU cores, and patches ETW (Event Tracing for Windows) logging to reduce detection by security monitoring tools. A watchdog subsystem also continuously checks for debuggers and instrumentation tools while the malware is running.

Conclusion

TCLBanker is a sophisticated banking trojan that combines credential harvesting, live remote session control, and self-propagation to specifically target Brazilian internet banking users. Its deep anti-analysis protections, DLL-sideloading delivery, and ability to spread through victims' own trusted accounts make it harder than average to catch and contain.

Victims can face unauthorized financial transactions, stolen banking login credentials, identity theft, and broader account compromise from the shell access operators gain during an active session. The malware should be removed from the system immediately.

More examples of banking trojans are CHAVECLOAK, Ares, and Javali.

How did TCLBanker infiltrate my computer?

According to Elastic Security Labs, TCLBanker is distributed as a trojanized version of the Logitech Logi AI Prompt Builder installer, packaged inside a ZIP archive. When the victim runs the MSI, a legitimate Logitech executable is tricked into loading a malicious DLL (screen_retriever_plugin.dll) placed next to it - a technique called DLL sideloading. That DLL then decrypts and executes the banking trojan payload in memory.

Once one machine is infected, TCLBanker spreads itself automatically. It takes over the victim's authenticated WhatsApp Web browser session to send phishing messages to all of their contacts, and uses the victim's own Outlook account via COM automation to send phishing emails to recipients in their address book. Because the messages come from a real, recognized account, recipients are more likely to trust them and run the installer link inside.

More broadly, threats of this kind also reach victims through unsolicited phishing emails from unknown senders, malicious advertisements, fake software download sites, and software cracks and key generators shared through torrent and file-sharing networks.

How to avoid installation of malware?

Be cautious about unexpected messages - even from people you know. If a WhatsApp contact or a colleague's email contains an unusual link or attachment you were not expecting, verify with them through a separate channel before clicking or downloading anything. Download software only from official developer websites or verified app stores, and be wary of installers delivered as ZIP files from unfamiliar sources. Keep your operating system and all applications updated so that known vulnerabilities cannot be exploited before you patch them.

Avoid pirated software, key generators, and unofficial activation tools, as these are among the most common delivery vehicles for banking trojans and similar malware. Use a reputable security program and run scans regularly to catch threats that slip past initial defenses. 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

---

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

---

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

---

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

---

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

---

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

Formatting will remove TCLBanker, but it also erases every file on the drive. Running a trusted security tool such as Combo Cleaner is a safer first step and should be sufficient in most cases to remove the infection without any data loss.

What are the biggest issues that TCLBanker malware can cause?

TCLBanker can intercept live banking sessions, display fake login overlays to steal credentials, and allow operators to remotely observe and control the infected machine. This can lead to unauthorized bank transfers, loss of access to financial accounts, identity theft, and the spread of the malware to the victim's own contacts through WhatsApp and email.

What is the purpose of TCLBanker malware?

TCLBanker is designed to steal banking credentials and facilitate fraudulent transactions against Brazilian banking users. It monitors browsers for visits to targeted financial sites, activates a fake overlay session to deceive victims into surrendering their login details, and gives the operator real-time access to the compromised machine during that session.

How did TCLBanker malware infiltrate my computer?

TCLBanker has been documented spreading through a trojanized Logitech Logi AI Prompt Builder installer delivered in a ZIP archive, as well as through phishing messages sent automatically from infected users' own WhatsApp and Outlook accounts. More broadly, threats of this kind also reach victims via phishing emails from unknown senders, fake software download pages, malicious advertisements, and pirated content.

Will Combo Cleaner protect me from malware?

Yes. Combo Cleaner can detect and remove most known malware, including banking trojans like TCLBanker. Because sophisticated threats can embed themselves deeply in the system, running a full scan is the best way to confirm the infection has been fully cleared.