Remove the FireBird Remote Access Trojan (RAT) from the operating system

What kind of malware is the FireBird RAT?

FireBird is a Remote Access Tool (or alternatively, when used in a malicious capacity, it is termed a Remote Access Trojan) or 'RAT'.

On initial inspection, this may seem to be a legitimate piece of software, however, its list of capabilities/features (e.g. anti-detection, functionality without input or permission of the connected machine's user, etc.) clearly indicate that FireBird was developed with malicious use in mind.

Furthermore, this program is offered for purchase in a cryptocurrency, the transactions of which are difficult/impossible to trace due to the lack of personal information required. Therefore, cyber criminals wishing to purchase this dangerous software can remain anonymous.

FireBird allows remote access and control over an infected device. It can be used in various dangerous ways that endanger system integrity and user safety.

FireBird RAT overview

The FireBird RAT is highly functional malware with various capabilities. Some examples of its functions and potential misuse follow. FireBird can allow cyber criminals user-level control over a targeted machine.

This malicious software can manage Windows Registry (containing information, parameters, options and other values of software and hardware installed on the system). Therefore, it can give commands to install/uninstall applications and control connected hardware.

The latter can be used to turn the monitor on/off, enable/disable the mouse, open/close the CD player, record audio via the microphone, record via the webcam, play audio, etc. Any recorded material can be used for blackmail purposes. FireBird can interact with Task Manger and end any running processes, including that of Task Manager itself.

Coupled with its capability to infiltrate data and execute (i.e., run) programs, it can cause chain infections (i.e. download/install additional malware). FireBird can exfiltrate data stored in the system and browsers such as Google Chrome and Mozilla Firefox. It can also recover log-ins and passwords from these browsers and QQ messenger, FileZilla file transfer application, etc.

This RAT has keylogging capabilities (it can record key strokes). This capability is used to steal the credentials (i.e., log-ins and passwords) of various accounts such as emails, social networking, social media, e-commerce, financial/banking and so on.

Communication accounts can be misused by criminals to demand money from the genuine owner's contacts/friends and to further malicious software. E-commerce (online store) accounts often save credit card details. Thus, cyber criminals can use them to make online purchases.

FireBird can also mine certain cryptocurrencies. These are some examples of how this malware can operate and the misuse it can facilitate. To summarize, FireBird can cause additional system infections, lead to significant financial loss, serious privacy issues and identity theft.

If you suspect that FireBird (or another malicious program) has already infected the system, remove it using anti-virus software immediately.

More examples of RATs

NetWire, Koadic, BlackNix and PiXie are some examples of other remote access Trojans. While their functionalities may differ, they have just one purpose: to generate revenue for the cyber criminals using them. Regardless of how they work, they can cause serious problems. Therefore, it is paramount to remove all malware without delay to ensure device and user safety.

How did FireBird infiltrate my computer?

Since FireBird is available for purchase online, its proliferation methods can vary depending on the cyber criminals using it. Malware is usually spread via spam campaigns, backdoor Trojans, illegal activation tools ("cracks"), bogus updates and untrusted download channels.

Spam campaigns are used to send deceptive emails containing infectious files attached to (or linked inside) them. Infectious files come in variety of formats (e.g. PDF and Microsoft Office documents, archive and executable files, JavaScript, etc.). When these are executed, run or otherwise opened, the infection process is triggered.

Some Trojan-type malware is capable of downloading/installing additional malicious programs. Rather than activating licensed products, illegal activation ("cracking") tools can download/install malicious software. Fake updaters infect systems by abusing flaws of outdated products and/or simply installing malware rather than the promised updates.

Disguised malicious content if often downloaded unintentionally from untrusted sources (e.g. unofficial and free file-hosting websites, Peer-to-Peer sharing networks and other third party downloaders).

How to avoid installation of malware

You are advised against opening dubious or irrelevant emails, especially any attachments or links present in them, due to the risk of malware infections. Use only official and verified download channels. Activate and update products with functions/tools provided by legitimate developers.

Illegal activation tools ("cracks") and third party updaters are often used to proliferate malicious programs. It is crucial to have a reputable anti-virus/anti-spyware suite installed. Furthermore, keep this software up to date and run regular system scans for the removal detected/potential 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.

Screenshot of FireBird RAT process in Windows Task Manager ("MSBuild.exe" - the process name might vary):

Appearance of the website used to promote FireBird RAT (GIF):

Screenshot of a fake World Health Organization (WHO) website (unfoundation[.]website) used to spread FireBird RAT:

Screenshot of a malicious Microsoft Excel document ("DHL_Shipment_AWB5172133171.xls") used to spread FireBird RAT:

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

Formatting your storage device is one of the ways to ensure the malware is completely removed. However, before taking such drastic action, you should try removing it with trusted antivirus or anti-malware software.

What are the biggest issues that malware can cause?

The effects of malware depend on its type and capabilities. Common consequences include identity theft, financial loss, additional infections, data loss, and reduced device performance.

What is the purpose of FireBird RAT?

The FireBird RAT gives cybercriminals extensive control over infected systems. It allows them to manipulate the operating system, steal sensitive data, install additional malware, record keystrokes, and mine cryptocurrencies.

How did FireBird RAT infiltrate my computer?

Threat actors commonly deploy malware through outdated software, pirated programs, technical support scams, and phishing emails with malicious attachments or links. They also use P2P networks, compromised websites, fake software updates, infected USB drives, malicious ads, and similar channels.

Will Combo Cleaner protect me from malware?

Yes, Combo Cleaner can detect and remove nearly all known malware. However, advanced malware often hides deep within the system, so performing a full system scan is highly recommended.