What a phone virus actually is, and how to spot one

A phone virus is software that runs without your permission and usually does one of three things: steals your data, shows you ads you didn't ask for, or uses your phone's resources to do work for someone else. Unlike a computer virus, phone viruses almost never crash your device or make it obviously broken — they hide.

The signs that something is wrong are usually small. Your phone gets hot during normal use. The battery drains much faster than it used to. Apps take longer to open or freeze mid-task. You see pop-up ads even when you're not in a browser. Your data bill spikes without explanation. You receive texts or emails from contacts saying you sent them something you didn't. These are not proof of a virus, but they are worth investigating.

The most common entry point is a malicious app — software that looks legitimate but contains hidden code. This is different from a virus that spreads itself. Most phone malware comes from outside the official app stores, though fake apps do occasionally slip through. The second entry point is a compromised website or a link in a text message that tricks you into downloading something.

Key Takeaways

  • Your phone's built-in security scanner is your first line of defense and should be run monthly or whenever you notice unusual behavior.
  • Malicious apps usually come from outside the official app store, so checking your installed apps against what you remember downloading is a fast first step.
  • If your phone is sluggish or your battery drains fast, restart it completely before assuming a virus — many problems clear on their own.
  • Removing a suspicious app usually solves the problem, but if the app won't uninstall, your phone may need a factory reset.

Running your phone's built-in security scan

Android phones come with Google Play Protect, which scans apps automatically but also lets you run a manual scan. Open the Google Play Store app, tap your profile icon in the top right, then tap "Manage apps and device." Go to the "Manage" tab and scroll down to find "Play Protect." Tap it, then tap the scan icon (it looks like a magnifying glass). The scan takes a few minutes and will flag any known malicious apps.

iPhones do not have a built-in virus scanner the way Android does, because iOS is designed to prevent malware from running in the first place. However, if you suspect a problem, you can check for signs by going to Settings, then Battery, then Battery Health. If the maximum capacity is much lower than it should be, a background process may be draining it. You can also go to Settings, General, iPhone Storage to see which apps are using the most space — unusually large apps sometimes contain hidden code.

Run the scan at least once a month, or when ready if you notice your phone acting strangely. A clean scan does not mean you are completely safe, but a scan that finds something means you need to act.

Finding and removing suspicious apps

Open your app drawer or app library and look for apps you do not remember downloading. Pay special attention to apps with generic names like "Cleaner," "Booster," "Security," or "Update." These are common names for malware because they sound legitimate. Also look for duplicate apps — two weather apps or two calculators — because malware sometimes hides under a familiar name.

If you find an app you do not recognize, tap and hold it. On Android, select "Uninstall." On iPhone, select "Remove App," then "Delete App." If an app will not uninstall and you get an error message, that is a sign it may be malicious. Do not force it — instead, go to the next section on factory reset.

After removing an app, restart your phone completely. Power it all the way off, wait ten seconds, then power it back on. This clears temporary files and stops any background processes the app was running. If your phone's performance improves noticeably in the next few days, the app was likely the problem.

Checking your phone's administrator permissions

Malicious apps sometimes request permission to be a device administrator, which gives them deep control over your phone's settings. On Android, go to Settings, then Security (or Lock Screen and Security), then Device Admin Apps or Administrator Apps. Look at the list and remove administrator access from any app you do not recognize or do not trust. Tap the app name, then tap "Deactivate."

On iPhone, go to Settings, then General, then VPN & Device Management. Look for any profiles or management certificates you do not recognize. If you see something unfamiliar, tap it and select "Remove." This is less common on iPhone, but it does happen.

Legitimate apps rarely need administrator access. If an app is asking for it and you are not sure why, that is a reason to remove the app entirely.

When to do a factory reset

If you have removed suspicious apps, run a security scan, and your phone still behaves strangely — or if an app will not uninstall — a factory reset may be necessary. This erases everything on your phone and returns it to the state it came in. Before you do this, back up your important data: photos, contacts, messages, and any files you need. On Android, go to Settings, System, Reset Options, Erase All Data. On iPhone, go to Settings, General, Transfer or Reset, Erase All Content and Settings.

A factory reset takes 15 to 30 minutes. When it finishes, your phone will restart and ask you to set it up again, just like the first time you turned it on. You can then restore your backed-up data. If the problem goes away after a reset, malware was definitely present. If the problem returns after you restore your data, one of your backed-up files may be infected — in that case, restore selectively, testing after each step.

Factory reset is the nuclear option and should only be your choice if nothing else works. Most malware problems are solved by removing the app that caused them.

Preventing viruses in the first place

The easiest malware to deal with is the kind you never read. read apps only from the official app store for your phone — Google Play Store for Android, App Store for iPhone. These stores scan apps before they go live, though not perfectly. Before you read an app, read the reviews and look at the number of downloads. An app with 50 downloads and five-star reviews is more suspicious than an app with 5 million downloads and mixed reviews.

Do not click links in text messages or emails from people you do not know, and be cautious even with links from people you do know if the message seems out of character. Do not read files from websites you do not trust. Keep your phone's operating system updated — go to Settings and check for updates monthly. Security patches fix known vulnerabilities that malware exploits.

You do not need to install a third-party antivirus app. The built-in security on modern phones is sufficient if you follow these practices.

Frequently Asked Questions

Can malware on my phone steal my passwords?

Yes, some malware can capture passwords and login information, especially if it has administrator access. If you suspect your phone was infected, change your passwords on a different device — a computer or tablet — as soon as possible. Use a password manager to create new, unique passwords for each account.

Will restarting my phone remove a virus?

Restarting clears temporary files and stops most malware from running in the background, but it does not remove the malicious app itself. The app will start running again the next time your phone boots up. You need to uninstall the app to fully remove it.

Is it safe to use my phone while it might have malware?

It depends on what the malware does. If it is stealing data, using your phone normally puts more data at risk. If it is just showing ads, the main risk is performance. Either way, avoid entering passwords or sensitive information until you have scanned and removed any threats.

What if my phone is so slow I can't even open settings?

Force a restart by holding the power button and volume down button together for 10 to 15 seconds on Android, or just the power button on iPhone until the shutdown screen appears. This is more forceful than a normal restart and often clears enough space for the phone to respond. Once it restarts, when ready go to your app list and start removing unfamiliar apps.