How to remove TONResolver RAT from the operating system

What kind of malware is TONResolver RAT?

TONResolver is a Remote Access Trojan (RAT) written in JavaScript and run through the legitimate Node.js runtime. Once active, it opens a persistent encrypted connection to an attacker-controlled server and waits for instructions, giving operators the ability to execute code, retrieve files, and deploy additional payloads on the victim's machine.

According to research published by Trend Micro, the campaign was active from at least February to June 2026 and focused on employees of Japanese accommodation companies that partner with Booking.com. Attackers sent phishing emails posing as urgent guest complaints to trick hotel staff into downloading and running the malware.

What distinguishes TONResolver from most RATs is its use of The Open Network (TON) blockchain as a dead drop resolver. Instead of hardcoding a server address, the malware reads its active command-and-control (C&C) destination from a TON smart contract. If that server is blocked or taken down, the attacker simply updates the contract with a new address, and the infected machine connects there instead.

TONResolver RAT overview

After execution, TONResolver is loaded into a legitimate Node.js process. A custom VM-based obfuscation layer converts the malware's logic into a virtual instruction set processed by a built-in interpreter. This design makes the code extremely difficult to analyze through static inspection alone.

The malware's first runtime task is locating its C&C server. It queries a TON smart contract through the public tonapi.io API, calling the contract's "get_domain" method. The C&C server domain embedded in that contract is returned in the response, and the malware connects to it.

Once connected over an encrypted WebSocket, TONResolver transmits basic details about the victim's machine: username, hostname, OS version, CPU core count, available memory, and hardware MAC address. A keepalive ping runs every 20 seconds to hold the connection open and confirm to the attacker that the endpoint is still reachable.

TONResolver RAT features

All traffic between the infected machine and the C&C server is encrypted using ECDH secp256k1 key exchange, HKDF-SHA256 key derivation, and AES-256-CBC encryption. Because the WebSocket stream is fully opaque to packet inspection, detection through proxy analysis or network security monitoring is extremely difficult.

The RAT supports four main command types: running arbitrary JavaScript strings on the victim's machine, executing PowerShell commands, and retrieving and executing additional files sent by the attacker. This makes TONResolver an adaptable initial-access foothold that can be directed toward almost any follow-on objective.

Trend Micro's MDR team observed a follow-on executable deployed from a temporary folder after TONResolver established access. That executable targeted Chrome and Edge "User Data" directories, which store saved passwords, cookies, browsing history, and autofill data. TONResolver itself does not steal credentials - it provides the remote-access channel that lets the attacker deliver and run tools that do.

Persistence and defense evasion

To survive reboots, TONResolver adds a startup entry to the Windows Registry Run key (HKCU\Software\Microsoft\Windows\CurrentVersion\Run), causing the malware to relaunch automatically each time the user logs in. A Mutex check also prevents multiple copies from running at the same time.

The malware runs entirely inside Node.js, a widely used and trusted runtime. The Node.js binary is fetched from the official nodejs.org website during the infection chain, so no suspicious or unsigned executable needs to be bundled in the initial payload. This helps the malware blend into normal software activity on the endpoint.

The PowerShell loader also applies a server-side filter: it only serves the next-stage payload when the HTTP request's User-Agent string contains "Powershell." Requests from browsers, automated crawlers, or analysis sandboxes that do not match receive a 404 error, keeping the payload away from automated inspection.

Conclusion

TONResolver gives attackers persistent, encrypted remote access to infected systems and the ability to run arbitrary code, retrieve files, and install further payloads. Its use of the TON blockchain to conceal the C&C server address makes it significantly harder to disrupt through conventional takedown methods.

Victims face the risk of credential theft from browsers, account hijacking, identity theft, and potentially much deeper system compromise. TONResolver should be removed from any infected system immediately.

More examples of RATs are QuimaRAT, msaRAT, and Dolphin X.

How did TONResolver RAT infiltrate my computer?

According to Trend Micro, TONResolver was spread through phishing emails targeting Japanese accommodation companies that partner with Booking.com. Messages posed as urgent guest complaints about issues such as bed bug infestations and included fake reservation details along with a link labeled "Download Photos and Videos."

A second distribution method observed in this campaign was a "conversational attack" carried out through Gmail. Attackers first sent an ordinary inquiry email and waited for a reply. After receiving a response, they followed up with a message containing the malicious link - a two-step approach that builds initial trust and is harder to recognize as a threat than a cold unsolicited message with an attachment.

Clicking the link downloaded a zip archive containing an LNK shortcut file disguised as a photo. Running the shortcut triggered a chain of PowerShell commands that fetched and executed a script, which then downloaded Node.js and the TONResolver JavaScript payload. More broadly, malware of this kind also reaches victims through software cracks, unofficial download sites, malicious email attachments, and social engineering through other messaging platforms.

How to avoid installation of malware?

Be cautious with unexpected emails, especially those urging you to click a link or open an attachment. Attackers increasingly disguise messages as legitimate business communications - complaints, invoices, or notifications from known services. Always verify the sender's actual email domain before interacting with any link or file, and download software only from official sources.

Keep your operating system and installed applications updated, as patches close vulnerabilities attackers depend on. Use a reputable security tool with real-time protection and run regular scans. 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

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

Formatting removes the infection but also erases every file on the drive. Running a reputable security tool such as Combo Cleaner is the safer first step in most cases - formatting should be treated as a last resort.

What are the biggest issues that TONResolver RAT malware can cause?

TONResolver gives attackers remote access to the infected system and lets them deploy credential-stealing tools, execute arbitrary commands, and install further malware. This can lead to stolen passwords, account hijacking, identity theft, and financial loss.

What is the purpose of TONResolver RAT malware?

TONResolver is designed to give attackers a persistent, encrypted remote-access foothold on infected machines. Operators can use it to execute commands, retrieve and run files, and stage follow-on attacks such as credential theft or additional malware deployment.

How did TONResolver RAT malware infiltrate my computer?

TONResolver has been observed spreading through phishing emails that impersonate Booking.com guest-complaint notifications, targeting Japanese hotel staff. Clicking the link in the email downloaded a zip archive, and running the shortcut file inside triggered the malware installation chain via PowerShell and Node.js.

Will Combo Cleaner protect me from malware?

Yes. Combo Cleaner can detect and remove most known malware infections. Because sophisticated threats can hide deep in the system, running a full system scan is recommended to ensure nothing is missed.