How To Detect Malware on Your Computer or Phone

How Do You Know If Your Device Has Malware? 

Malware can give cybercriminals access to your computer, sensitive personal data, and online accounts (including your email and online banking). That’s what happened to one Pennsylvania resident. After being tricked into downloading a malicious program, the victim lost over $600,000 of his life savings [*].

In 2022 alone, there were more than 10.4 million reported malware attacks [*].

While antivirus software has traditionally served as the best way to detect malware before it can do too much damage, it’s not enough to protect you against modern threats. 

In this guide, we’ll explain how to recognize the warning signs of a malware attack, how to remove viruses from your computer, and what you can do to keep yourself and your family safe from online scammers.

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12 Warning Signs That Your Device Has Malware

Computer viruses are malicious software programs designed to exploit computer system and device vulnerabilities. Hackers create countless types and variants of malware to steal sensitive personal data or coerce people into giving them money, access to valuable accounts, or remote control of devices. 

For example, a keylogger can record your keystrokes whenever you access your emails, banking, and social media. In August 2023, news broke that the FBI had taken down QakBot. The Russian-linked trojan horse had infected more than 700,000 endpoints, creating a bot army to target government organizations [*]. 

If your smartphone or laptop has a virus, it may be evident immediately — such as with ransomware attacks that lock you out of your device or browser. However, some types of malware remain hidden as they silently infiltrate your devices to let hackers spy on you and steal your sensitive information. 

Here are 12 warning signs of malware threats: 

1. Alerts from your antivirus software

A reliable antivirus software is the first line of defense against malware. Pay attention to warnings from your security software, as this could help you avoid a serious data breach. However, be cautious of fake alerts — which can deceive you into clicking on harmful links.

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2. Your device is slow or crashes all the time

Malicious software can put strain on your system’s central processing unit (CPU), depleting your battery and causing disruptions as you use your computer. If your laptop or smartphone suddenly slows down or starts crashing frequently, it could mean you've been hacked and have a malware infection.

3. You’re constantly being redirected to strange websites

Browser-hijacking malware sends people to risky websites as they browse. If you end up on a malicious website, you could expose personally identifiable information (PII) to identity thieves. Watch out for any strange redirects when you’re online, and take care not to share your information on unfamiliar websites. 

4. Constant pop-ups (or ransomware notices)

If you see a lot of pop-ups demanding payment, threat actors have installed ransomware on your computer. While these notices may seem like genuine warnings from your operating system or antivirus software, you should avoid making any transactions — as you will give your credit card information to scammers.

5. You can’t access your computer or online accounts

A common type of malware takes over your accounts or devices by encrypting your files or altering your login credentials. If you ignore best practices for password management, someone could gain unauthorized access to your accounts — and lock you out.

6. Your mouse moves on its own

If your mouse cursor suddenly has a mind of its own, this is a clear warning sign that you’ve been hacked. If an unauthorized person gets remote control of your device, they could access sensitive files, email inboxes, and social media accounts. 

7. Unfamiliar files or folder changes

Unexpected modifications to your files are red flags that you shouldn’t ignore. If someone makes changes to your device, it could compromise your data, privacy, and even your identity. It’s important to try and detect malware and isolate threats before intruders can cause serious damage.

8. Higher than usual data usage on your mobile devices

Most people won’t spot a spike in data usage until they get a hefty phone bill. With a vigilant approach to monitoring how much you use your mobile data, you can spot early warning signs of a malware infection or a hacked phone.

To check your data usage:

• On iOS devices: Go to Settings > Mobile Data.
• On Android devices: Navigate to your phone's Settings > Network & internet > SIMs > App data usage.

9. Strange emails in your “sent” folder

It can be a shock to find emails in your “sent” folder that you never created — especially if they were sent to your family members, work colleagues, or your bank! If this happens to you, scan to detect malware immediately. It’s possible an imposter hacked your email account and used it to send phishing emails, which poses a risk to you and anyone who received an email from your account. 

10. Unexpected apps running in the background 

If your device becomes sluggish, it may not be age —  but, rather, an external threat. The first thing you should do is check the apps that are running. If you detect unauthorized apps, hackers might have installed adware or spyware on your device. 

11. Your antivirus, firewall, or digital security tools have been disabled

Some sophisticated malware can evade modern security tools and even disable them ‚ including virtual private networks (VPN) that you use to protect your Wi-Fi network. Without robust digital defenses, you’re at risk of financial fraud or identity theft every time you go online. You can stay safe by making a habit of regularly verifying that your digital security tools are active and updated. 

12. Your device is making strange sounds

Because malware makes your device work harder, this can reveal some physical telltale signs. If your phone feels hot or your laptop gets loud, it’s worth finding out why. A quick investigation could help you detect malware or another issue that is impacting your device’s performance.

💡 Related: How Hackers Get Into Your Computer (And How To Stop Them) →

How To Remove Malware From Your Computer or Phone

1. Download and install antivirus software
2. Don’t enter any passwords, and stay offline
3. Boot up your computer in Safe Mode 
4. Run a full security scan to quarantine viruses
5. Delete temporary files, and clear your browser cache
6. Wipe your device, and restore to a (virus-free) backup
7. Update your operating system and software
8. Change your passwords, and enable 2FA

If you spot warning signs of malware, it’s critical to take action immediately. You must isolate and eliminate malicious programs before threat actors seize control of your device or steal sensitive information.

If you think your device has a virus, here are eight malware protection tips to help remedy the situation:

1. Download and install antivirus software 

Anti-malware software scans your devices, emails, apps, and text messages for malicious code or links. If you have control of your device (and haven't already installed an antivirus), choose a reputable company that provides comprehensive coverage to scan for trojans, spyware, and ransomware threats.

2. Don’t enter any passwords, and stay offline

As soon as you realize your device could be compromised, disconnect from the internet. 

By staying offline, you reduce the risk of the virus spreading or sending back sensitive information to the hacker. If cybercriminals have remote access to your computer, cutting the connection can stop them from exploring your device or contacting others from your online accounts. 

💡 Related: Do Scammers Have Remote Access To Your Computer? Do This →

3. Boot up your computer in Safe Mode

When you boot up a computer in Safe Mode, the system only loads the bare minimum required to run your device — which can stop the virus from spreading while you sort out what to do next. 

Here’s how to boot up your computer in Safe Mode: 

• For Windows PC: From the Windows sign-in screen, hold down the Shift key and select Power and then Restart. When your computer reboots, select Troubleshoot, Advanced Options, Startup Settings, and Restart. A different menu will display this time. Select F4 to start your PC in Safe Mode.
• For Mac OS X: Turn on or restart your computer, and immediately hold down the Shift key until the login window appears. You should see a Safe Boot option in the menu bar. If not, log in to your computer like you usually do. A second login screen that includes the Safe Boot option should then appear.

If the problem you spotted doesn't happen when using Safe Mode, the default device settings and drivers aren't the problem. 

4. Run a full security scan to quarantine viruses

With your computer in Safe Mode, run a full scan (also sometimes called a “deep scan”) to detect and quarantine any malware. 

Take time to review the scan results, and follow prompts to quarantine or remove detected threats before they cause harm to your device. Also, ensure that your programs are up to date in order to defend against flaws and vulnerabilities. 

If you don’t have a third-party digital security provider, you can use the built-in antivirus scanner to detect malware and eliminate cyber threats:

• On Windows computers: Windows Defender (or Windows Security in newer versions) is the native antivirus program that provides real-time protection against malware.
• On macOS devices: XProtect helps identify known malware and stop users from accidentally opening malicious files.
• On Android devices: You can use Google Play Protect to scan for anomalies and ensure the safety of new apps before you download anything from the Google Play Store.

Using a built-in scanner is a convenient and cost-effective option that works seamlessly with your operating system. However, remember these native tools are limited in how much they can protect you if you fall victim to fraud. 

💡 Related: How To Tell If Your Computer Has a Virus →

5. Delete temporary files, and clear your browser cache

Bogus programs can sometimes evade malware detection tools. Deleting your temporary files and cache eliminates a potential hiding place for hackers to plant malicious programs. 

Here’s what to do:

On Windows: 

• Access the Disk Cleanup utility by typing “Disk Cleanup” into the Windows search bar. Once it opens, you'll be prompted to select your system drive, which is usually labeled as C:. 
• Choose the categories to clean. The Temporary files option is crucial if you want to remove unfamiliar or suspicious files that could contain malware.
• After selecting categories, select OK and proceed by clicking on Delete Files to confirm your choices.

On macOS: 

• Start by opening Finder and navigating to the menu bar. 
• Select Go > Go to Folder to open a dialog box.
• Enter "~/Library/Caches." 
• After confirming, you will be directed to the Caches folder. You can select and remove the contents within this folder, clearing your cache of any undesired files.

On Web Browsers: 

• Open your browser's Settings or Preferences menu (such as Chrome or Firefox). 
• Look for the option to Clear browsing data. 
• Once selected, you can specify the types of data to remove, including cached images and files. 

6. Wipe your device, and restore to a (virus-free) backup

If malware infects your device, a factory reset may be the only way to eliminate the virus. This extreme option is effective, but you can lose a lot of your files and important information in the process.

The process for a factory reset differs, depending on the device:

For Macs, iPads, or iPhones: 

• Follow the steps on Apple’s website.

For Android phones and tablets:

• Go to Settings > General Management > Reset.
• Tap on Factory data reset.

For Windows:

• Select Start > Settings.
• Go to Update & Security, then select Recovery (on Windows 11 computers, it’s System, then Recovery).
• Under Reset This PC, select Get Started (or Reset PC in Windows 11).
• Select Remove Everything. If you choose Keep My Files, there’s a chance junk files and malware might remain.

It’s worth backing up everything before you wipe your device. You can use cloud backup and external drives to save important files, including photos, videos, and paid downloaded materials. 

After wiping your device, follow the instructions to restore it from an earlier backup that is free of malware. All the apps and files you installed after you got the device will be removed. Also, any pre-installed apps will be reinstated. 

Note: A factory reset can't remove all viruses. While your phone may be back to its original state, some sophisticated viruses hide deep in your device's hardware or operating system and can avoid being wiped during a clean install.

💡 Related: How To Know If Your Phone Is Hacked (and What To Do) →

7. Update your operating system and software

Software providers release updates to patch known zero-day vulnerabilities and ensure that your device remains compatible with new features. By staying in sync with the latest version of your operating system and software programs, you can detect malware and protect against emerging cyberattacks.

Pro tip: Enable automatic updates for your operating system and software whenever possible. This step ensures that you receive the latest patches and features without having to do anything.

💡 Related: How To Remove Viruses From Your Computer (Mac and PC) →

8. Change your passwords, and enable 2FA

The unfortunate truth is that 80% of hacking-related data breaches are linked to compromised passwords [*]. While viruses might seem like a bigger issue, weak or reused credentials are more likely to put you at greater risk. 

Here are three best practices to improve the defenses of your online accounts:

• Create strong passwords. You can reduce the chance of account takeover fraud by creating complex, unique passwords that combine uppercase and lowercase letters, numbers, and symbols. 
• Use a password manager. It’s hard to remember complex passwords for all of your accounts, such as email, social media, and banking. But instead of subjecting yourself to the risks of reusing passwords, you can create and store unique login credentials in Aura’s secure password manager — which remembers everything for you.
• Enable two-factor authentication (2FA). With a second authentication factor in the login process, it’s more difficult for someone to gain unauthorized access to your accounts. Hackers might get your password; but it’s hard for them to bypass 2FA if you use a fingerprint scan or hardware security key. 

Are Free Antivirus Tools and Tech Support Services Safe To Use? 

If your computer has been hacked or infected, you might go looking for help. And while free tools or tech support seems appealing, these are often scams in disguise. 

Fraudsters create bogus tools and place ads for tech support to lure unsuspecting victims. Tech support scammers also make calls to vulnerable targets — like older adults, who tend to be less tech-savvy.

If you end up on the phone with these imposters, they could trick you into granting them remote access to your computer. 

Here are seven ways to avoid scam tools and fraudulent support teams:

• Whenever possible, use reputable providers. Sticking to trusted vendors rather than unknown third-party tech support companies is best. Companies like Microsoft and Apple offer complimentary tech support services when you purchase their devices. 
• Research lesser-known companies: It’s important to do your due diligence and research any tool or company. Read online ratings and customer reviews to verify that you are considering a legitimate company. 
• Always contact companies and support representatives by using their official platforms. Phishing only works if you click on the links or attachments in bogus emails. If you have a tech issue, make contact with customer support through the details listed on the company’s official site. 
• Never give anyone remote control. You should know and trust the individual to whom you provide access — preferably in person. If someone calls or emails you claiming to be from tech support, do not give them access, and never download remote access software like AnyDesk or TeamViewer — regardless of how convincing the tech support representative appears to be. 
• Use a privacy-focused browser. Services like DuckDuckGo are built to protect you and your data. Aura also includes an ad-blocker to protect your privacy and combat pop-up ads.
• Learn about phishing scams. Not everyone knows the warning signs of a tech support phishing email. Red flags include unsolicited advice from unknown senders, a sense of urgency in tone or language, and suspicious links. When you know what to look for, you can spot the scams.
• Consider signing up for an identity theft protection service. You can secure your data and devices with a dedicated platform that offers 24/7 monitoring of your online accounts, credit files, and bank accounts. The best providers send fast alerts if they detect malware or suspicious activity. 

💡 Related: Is Avast Antivirus Safe To Use? What To Know Before You Buy →

The Bottom Line: Avoid Malware at All Costs

With the cost of cybercrime set to surpass $8 trillion in 2023, you need to do more than ever before to combat hackers [*]. 

Start by installing a trustworthy digital security setup and practicing cyber hygiene. For added security and peace of mind, Aura offers an all-in-one solution to shield your online, financial, and personal accounts from malware threats.

Aura’s #1-rated identity theft protection helps safeguard your devices and accounts with a password manager and military-grade VPN. Plus, Aura’s antivirus software runs scans constantly to detect malware or hacking threats — and sends the fastest alerts in the industry.

If disaster strikes, all Aura plan members are covered by a $1,000,000 insurance policy along with access to 24/7 White Glove Fraud Resolution Specialists to help navigate the fraud recovery process.

Secure yourself against scammers and hackers. Try Aura free for 14 days.