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For a Windows PC, the most defensible starting point is Microsoft Defender Antivirus, with Microsoft Safety Scanner as an additional on-demand removal check. Malwarebytes is another vendor-supported scan option. None can promise detection of every RAT: attackers may abuse legitimate remote-access software that looks normal to antivirus, antimalware, and EDR tools.
What the evidence actually supports
There is no current, independent head-to-head test that measures these products against the same, defined collection of remote-access trojans (RATs). That means it would be misleading to publish a detection-rate leaderboard or call one product the universal winner. The useful comparison is functional: which tool provides continuous protection, which is an on-demand second opinion, what each vendor claims, and what happens after a detection.
Microsoft identifies Microsoft Defender Antivirus for Windows 10 and Windows 11 and Microsoft Safety Scanner as free Microsoft software for detecting or removing trojans. Microsoft describes Defender as an antimalware product and Safety Scanner as a removal aid. Malwarebytes recommends its anti-malware product for mitigating a potential RAT infection. Those are official product recommendations, not independent comparative measurements.
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| Option | Primary role | What the cited guidance establishes | Important limitation |
|---|---|---|---|
| Microsoft Defender Antivirus | Built-in, ongoing antivirus protection on Windows 10 and 11 | Microsoft lists it as free software for detecting and removing trojans. | No cited source says it is the best RAT detector, and a clean result cannot rule out abuse of legitimate remote-access tools. |
| Microsoft Safety Scanner | On-demand removal and checking tool | Microsoft says it helps remove malicious software and lists it as a free trojan-detection/removal option. | Microsoft explicitly says it does not replace an antimalware product. |
| Malwarebytes | Vendor-supported antimalware scan and remediation option | Malwarebytes says its product can help remove RAT-associated files and registry modifications. | This is vendor guidance, not a controlled test or guarantee of removal. |
How to compare RAT scanners realistically
Use four questions rather than a made-up score. First, is the product an ongoing antivirus layer or an on-demand utility? Ongoing protection can monitor files and activity continuously, while a second-opinion tool only helps when you launch it. Second, what evidence supports the recommendation? Microsoft and Malwarebytes describe their own products, but that is different from an independent laboratory test using a controlled RAT sample set.
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Third, what threats are in scope? A scanner may identify a malicious executable, a dropped component, or registry modifications. It may not identify an attacker who uses a legitimate remote-support application, a stolen account, or an already-approved administrative tool. Fourth, what is the response plan after detection? Quarantine and deletion matter, but so do password resets, session revocation, administrator notification, and investigation of other devices.
All three named options are downloadable software rather than hardware products. The cited guidance confirms free Microsoft options, but it does not establish current subscription prices, discounts, affiliate terms, or a Malwarebytes cost comparison. Confirm present licensing and compatibility on the vendor’s own page before installing.
Why RAT detection is harder than ordinary malware scanning
A remote-access trojan can give an attacker covert surveillance and unauthorized control of a device. Malwarebytes describes capabilities such as monitoring behavior, changing settings, browsing or copying files, and collecting information. A malicious program may therefore expose documents, credentials, communications, cameras, microphones, or other sensitive data while trying to remain unnoticed.
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“Remote access software is often used for legitimate purposes, so it generally blends into the environment and does not trigger antivirus (AV), antimalware, or endpoint detection and response (EDR) defenses.”
This is the central qualification for any “best scanner” list. Scanning is one layer of defense against malicious files. It is not proof that every unauthorized remote session, stolen account, or misuse of an approved remote-access tool has been found.
1. Microsoft Defender Antivirus: the baseline for Windows
Defender is the practical first step for a Windows 10 or Windows 11 user because Microsoft includes it in the operating system and identifies it as a free tool for detecting and removing trojans. It is intended to provide ongoing antimalware protection rather than a one-time check.
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Use Defender before adding another scanner
- Open Windows Security from the Start menu.
- Select Virus & threat protection.
- Check the protection status and install any pending security intelligence or Windows updates offered by the system.
- Run a Quick scan for an initial check. If you suspect a RAT, open Scan options and choose a more thorough scan available on your edition, such as a full scan.
- Review the result under Protection history. Follow the offered action to quarantine or remove a detected item, and restart if Windows requests it.
Menu names can differ slightly by Windows release. The important distinction is that Defender remains the continuing protection layer; an additional scanner should supplement it rather than become the only defense.
When Defender is a sensible choice
- You need a no-cost starting point on a supported Windows 10 or 11 computer.
- You want protection that stays active instead of a scan you must remember to launch.
- You are checking a suspected file-based trojan before escalating to an administrator or security team.
A negative Defender scan narrows the possibilities but does not establish that an attacker has never accessed the machine. If a legitimate remote-access utility is being abused, its normal executable and network behavior may not look malicious to a conventional antivirus engine.
2. Microsoft Safety Scanner: a supplemental removal check
Safety Scanner is useful when you want a separate, on-demand Microsoft check or when Microsoft’s guidance directs you toward a removal tool. Microsoft says, “Microsoft Safety Scanner helps remove malicious software from computers.” The same guidance warns: “NOTE: This tool doesn’t replace your antimalware product.”
How to use Safety Scanner safely
- Obtain the current Safety Scanner release from Microsoft’s official download page. Use the version that matches your Windows system architecture and confirm that the download is current; the tool is updated periodically.
- Save the executable locally and launch it with an account permitted to perform malware removal.
- Accept the license terms, select the scan type offered by the tool, and allow the scan to complete without shutting down the computer.
- Read the final report and apply the removal action for anything identified.
- Restart if requested, then run your regular antimalware product again. Safety Scanner is an additional check, not a replacement for ongoing protection.
Because it is an on-demand utility, Safety Scanner is best viewed as a second step after Defender or as a targeted removal aid. Running it does not create a permanent monitoring service, and the absence of a finding does not address an attacker’s use of an otherwise legitimate remote-access program.
3. Malwarebytes: another vendor-supported scan option
Malwarebytes describes RATs as programs that can enable covert surveillance and unauthorized access. Its guidance recommends installing and running its anti-malware product to help mitigate a potential infection by removing associated files and registry modifications.
A practical Malwarebytes workflow
- Download the current product only from the vendor’s official source and keep the installer unchanged.
- Install it alongside your existing protection only when the product and your Windows configuration support that arrangement; avoid disabling your primary protection casually.
- Update the malware database when prompted, start a threat scan, and let it finish.
- Review each detection before quarantining or removing it, especially on a managed computer where an administrator may need the evidence.
- Restart when requested and preserve the scan report for your administrator or incident-response contact.
The vendor’s recommendation is useful for remediation, but it is not an independent comparison and does not guarantee that every RAT component has been found. A scan can remove files and registry modifications while an attacker still has access through a separate account, stolen credentials, or an approved remote-access application.
Which scanner should you use?
| Your situation | First action | Why | Do not assume |
|---|---|---|---|
| Normal Windows 10 or 11 use | Keep Microsoft Defender Antivirus active and updated. | It is Microsoft’s built-in, free ongoing antimalware layer. | That a clean scan proves there was no unauthorized remote access. |
| Concern about a file-based trojan or incomplete removal | Run Microsoft Safety Scanner as an additional check. | Microsoft positions it as a free removal aid. | That it replaces your antimalware product. |
| Need another vendor’s remediation scan | Run a Malwarebytes threat scan and review its report. | Malwarebytes specifically discusses removing RAT-related files and registry changes. | That vendor guidance equals an independent detection benchmark. |
| Company-managed laptop or server | Contact the organization’s administrator or security team before extensive cleanup. | They may need endpoint telemetry, account controls, and incident records. | That consumer scanning alone is sufficient. |
What to do if a scan finds a RAT
Treat a confirmed RAT as a potential exposure of any information reachable from that device. Malwarebytes advises changing usernames and passwords from a clean computer and notifying an appropriate administrator when applicable.
- Stop using the suspected device for sensitive sign-ins. Use a separate, trusted computer or phone for account recovery.
- Change passwords from the clean device. Start with email, password-manager, financial, workplace, and administrator accounts. Do not reuse the old passwords.
- Notify the right administrator. For a work, school, or shared device, contact the IT or security team before deleting evidence or reinstalling software.
- Record what the scanner reported. Keep the detection name, file path, time, actions taken, and scan report. This information can help determine whether other accounts or devices require attention.
- Follow the organization’s containment and recovery process. A managed environment may need account resets, endpoint investigation, or network controls that a consumer scanner cannot perform.
Removal of a file is not the same as proving that an intruder’s access has ended. If passwords were captured, changing them is necessary even after the malware is quarantined.
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Why a clean scan does not rule out compromise
There are several distinct possibilities after a scanner reports no malware:
- The suspected RAT file was never present, and the warning came from a legitimate remote-support session.
- The malware variant is newer or modified enough that the scanner’s signatures and behavioral rules do not identify it.
- The attacker is using legitimate remote-access software, which CISA says can blend into normal activity and avoid AV, antimalware, and EDR alerts.
- The device is clean now, but an account or session token was stolen earlier and is being used elsewhere.
For that reason, investigate the event that prompted the scan: unexpected remote-control windows, unknown support tools, new administrator accounts, unexplained settings changes, or suspicious account activity. On an organization-owned device, let the security team correlate endpoint and network telemetry instead of relying solely on a local scan.
Measures for organizations beyond a consumer scan
CISA’s remote-access guidance focuses on detecting and controlling legitimate tools that threat actors misuse. Related Microsoft guidance cited for 2026 recommends cloud-delivered protection, endpoint detection and response (EDR) in block mode, and network egress filtering as mitigation approaches. These are organizational controls, not features that a home user can assume a downloadable scanner provides.
- Cloud-delivered protection can provide security intelligence beyond what is stored locally.
- EDR in block mode is intended to detect and stop suspicious endpoint behavior, subject to the organization’s configuration and visibility.
- Egress filtering can restrict unauthorized outbound connections, reducing the usefulness of a compromised host to an attacker.
Administrators should also inventory approved remote-access software, remove tools that are no longer needed, restrict who can use them, and investigate unusual remote sessions. A consumer malware scan cannot substitute for those governance and monitoring measures.
Choosing a scan order and documenting results
A repeatable sequence prevents confusion. Start with the active protection already on the Windows device, confirm that it is updated, and run an initial scan. If the concern remains, use Safety Scanner as the separate Microsoft removal check or run Malwarebytes as the additional vendor-supported scan. Do not interpret two clean reports as mathematical proof of safety; the products can share blind spots, especially when the activity comes from legitimate software.
Write down the date and time of each scan, the product and version, the scan type, detections, file paths, and action taken. Preserve reports before deleting files on a work or school device. This record helps an administrator distinguish a false alarm from a wider incident and shows whether the same item reappears after a restart.
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Keep the tools’ roles clear. Defender is the continuing layer. Safety Scanner is an on-demand utility whose own documentation says it does not replace antimalware. Malwarebytes is a remediation option described by its vendor. None of these descriptions supplies a current, apples-to-apples benchmark, and product support can change with new Windows releases.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Common mistakes when scanning for RATs
Installing several real-time antivirus products
More products do not automatically mean more protection. Keep one primary, supported real-time antimalware product configured correctly, and use an on-demand scanner only when its compatibility and purpose are clear.
Assuming “quarantine” answers the incident
Quarantine addresses the detected object. It does not reset credentials, revoke stolen sessions, or explain how the software arrived. Complete the account and administrator steps above.
Downloading an old scanner
Safety Scanner is periodically refreshed. Use the current release from Microsoft rather than retaining an old executable as if it were a permanent security tool.
Ignoring legitimate remote-access tools
Look for remote-support or remote-management applications that should not be installed or running. Their presence does not prove malicious activity, but CISA’s warning means they deserve investigation when access was unexpected.
Cleaning a managed computer without telling anyone
Deleting a detected file or reinstalling Windows may destroy useful evidence. On a company, school, or shared system, notify the responsible administrator first unless an established emergency procedure says otherwise.
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For Windows, Microsoft Defender Antivirus is the most practical baseline because Microsoft identifies it as free ongoing trojan protection. Microsoft Safety Scanner is a useful supplemental removal check, provided you remember Microsoft’s warning that it does not replace an antimalware product. Malwarebytes is another vendor-supported remediation option, but its guidance is not an independent ranking. Most importantly, no scanner can guarantee detection when an attacker abuses legitimate remote-access software. Use scanning together with clean-device password changes, administrator notification, and—where relevant—organizational EDR and network controls.
Frequently Asked Questions
Can a virus scanner detect a remote-access trojan?
It can detect many file-based trojans, and Microsoft lists Defender and Safety Scanner for detecting or removing trojans. However, a scanner may miss abuse of legitimate remote-access software, stolen credentials, or a modified threat. A clean result is not proof that no unauthorized access occurred.
Is Microsoft Safety Scanner a replacement for Defender?
No. Microsoft says Safety Scanner helps remove malicious software and explicitly says it does not replace an antimalware product. Use it as an on-demand supplemental check, not as permanent protection.
Which is better for a Windows RAT check: Defender or Malwarebytes?
The available guidance does not provide an independent head-to-head test or a defensible winner. Defender is the built-in ongoing baseline; Malwarebytes is a vendor-supported remediation option. Choose based on role and follow-up needs rather than an unsupported detection-rate claim.
What should I do if a scanner finds a RAT?
Stop sensitive activity on the device, change usernames and passwords from a clean computer, preserve the detection details, and notify the appropriate IT or security administrator. Removing the file alone does not reset stolen credentials or end every active session.
Can legitimate remote-access software be dangerous?
Yes. CISA and partner agencies said on June 6, 2023, that legitimate remote-access software often blends into normal environments and may not trigger antivirus, antimalware, or EDR defenses. Unexpected tools or sessions should be investigated even after a clean scan.
Do I need several antivirus programs to find a RAT?
No. Keep one supported real-time antimalware product active and use an on-demand scanner only as a compatible supplement. Multiple real-time products can conflict, and running several scans does not prove that a system is clean.
The Bottom Line
Use Microsoft Defender as the free Windows baseline, Safety Scanner as an additional removal check, and Malwarebytes as another vendor-supported option. None is a guaranteed RAT detector, particularly when attackers misuse legitimate remote-access software. After any finding, secure accounts from a clean device and involve the appropriate administrator.
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