It's a scenario straight out of a computer nightmare: Someone, somewhere, is secretly watching everything you do on your computer. They can see your files, read your messages, and even control your webcam or microphone. Not fun. 

This is what a remote access trojan (RAT) is designed to do. 

Fortunately, you can prevent, detect, and remove these awful programs in most cases. There are red flags to look for and basic online safety behaviors you can take to protect yourself.   

What is a remote access trojan (RAT)? 

A remote access trojan (RAT) is a type of malware that allows a hacker to control your device from anywhere in the world secretly. Malware, by the way, is a term for the invasive software program used by hackers – we used to call this sort of thing computer viruses.  

Once installed, a RAT acts like a digital spy. It can give the attacker full access to your computer, often without you realizing it’s there. They can: 

• Steal passwords and sensitive files 

• Monitor your screen and take screenshots 

• Keylogging – the program can track every key you press 

• Turn on your webcam or microphone 

• Install more malware 

• Use your computer for further attacks 

Even nastier, RATs are designed to stay hidden. You may not notice anything is wrong until your data is stolen.  

Sometimes, an angry ex-spouse or ex-partner can attempt to use a RAT to access your devices. This invasion of privacy is a form of abuse and, along with preventing and eliminating RATs, you should report the activity to the police.  

How do RATs infect devices? 

RATs don’t just magically appear. They need to sneak into your device, and criminals have a bag of tricks to make that happen. Here are some common methods:

• Phishing emails, texts, DMs, and calls: You receive an email, text, or social media direct message (DM) with an attachment or link that secretly installs the RAT when opened. Criminals have also been known to call victims to try to trick them into downloading a RAT.

• Malicious downloads: A free app, cracked software, pirated media, or game might come bundled with a hidden RAT.

• Fake updates: You’re tricked into downloading a “software update” that’s malware – some websites are built to scare you into downloading these fake updates or antivirus software.

• Compromised websites: Simply visiting a malicious website can trigger an automatic download – ideally, quality web browsers will alert you to attacks like this. However, you must still be cautious when surfing the web.  

Signs your computer might have a RAT 

Spotting a RAT isn’t always possible or easy, but there are a few clues to watch for: 

• Sluggish performance: Your computer slows down or freezes without explanation. 

• Unusual network activity: Your internet connection seems unusually busy, even when you’re not using it. You can usually check this by clicking the Network section in your computer's Setting menu.  

• Mysterious programs: Unknown apps or programs appear on your computer. 

• Unexpected pop-ups: Strange messages or pop-ups start showing up. 

• Camera or microphone lights turn on: Your webcam light flickers without you using it (though some RATs can disable the indicator light). 

If something feels “off,” it’s worth investigating. Many of the signs of a RAT are similar to detecting other types of computer viruses.  

How to prevent RAT infections 

Just like with real pests, preventing an infestation is much easier than dealing with the aftermath of a RAT. Here’s the good news: With a few smart habits, you can dramatically reduce your risk.

• Be wary of emails, texts, DMs, and calls: Don’t open unexpected attachments or click links from unknown senders. Look out for any message that seems scary, sudden, and urges you to act quickly. Also, if you don't recognize a phone number, you can always let it go to voicemail!

• Download from official sources: Avoid shady sites, pirated software, or unverified apps.

• Use antivirus software: A reputable antivirus program can block many RATs before they install. Your device might already have a quality antivirus program installed – check your security settings and do some research.

• Keep software updated: Security patches fix holes that hackers love to exploit. Always download and install software updates, especially operating system updates, ASAP. 

• Use a firewall: A firewall can help detect suspicious traffic to and from your device. You can often configure a firewall within the settings of your internet router. 

You can never be "hackproof," but these tips make it so you are a much harder target for the bad guys to take over.

How to remove a remote access trojan 

If you suspect a RAT, don’t panic...but do act quickly. If you're intimidated by computers, take your device to a trusted, well-reviewed computer repair service.  

1. Disconnect from the internet: This cuts off the hacker’s access immediately. 

2. Run a full antivirus scan: Use your security software to scan and remove the threat. Your device or computer likely comes with a built-in antivirus program, such as Microsoft Defender, which can be found in the Security section of your Settings.  

3. Check installed programs: Uninstall anything unfamiliar or suspicious. You can find a list in the Settings menu.  

4. Change your passwords: Assume all your passwords have been compromised. Start with the most important ones (banking, email) and move through the list. Reset passwords at each website. Make each password at least 16 characters long, complex, and unique to the account – use a password manager to store them all safely.  

5. Consider a factory reset: In severe cases, wiping your device and reinstalling the operating system is best bet to ensure that you get rid of the vast majority of RATs.      

After cleaning your device, stay vigilant. If you aren’t sure whether you’ve entirely removed the RAT, it’s well worth the money to consult a computer professional. 

Can someone control your phone remotely? 

Unfortunately, it’s not just computers that are at risk – remote access trojans also target smartphones. These attacks often spread through malicious apps, especially those downloaded outside of official app stores, or through phishing links sent by text, email, or social media. Once installed, a RAT on your phone can quietly spy on your messages, track your location, access your camera and microphone, and even record your screen.  

Common warning signs of a RAT include:  

• Fast-draining battery 

• Unexplained overheating 

• Strange pop-ups  

• High data usage 

• Unfamiliar apps suddenly appearing

If you suspect a problem: 

1. Put your phone in airplane mode to cut off outside access.  

2. Delete any suspicious apps.

3. Make sure your phone’s operating software (iOS or Android) is up to date.

4. If the issues persist, a factory reset may be necessary to remove the malware fully.

5. If you are having trouble, take the device to a professional, like at an Apple Store or an outpost of your wireless carrier.

To avoid RAT infestations on your phone, stick to trusted app stores, be cautious with links and downloads, and consider using a reputable mobile security app, particularly if you use an Android device. Some mobile antivirus software comes with web browsing and text phishing protection as well.  

You can take control of your security 

Remote access trojans serve as a reminder of the hidden threats that lurk online. But by understanding how they work and taking some simple precautions, you can keep your digital life secure. When in doubt, trust your instincts. If something feels wrong on your device, it’s always better to investigate sooner rather than later. And to get more online safety tips and tricks sent to your inbox, sign up for our free email newsletter!