What to look for on your phone right now

A virus on your phone usually shows itself through behavior changes you'll notice before any scan tells you something is wrong. Your phone may drain battery much faster than usual, run hot even when you're not using it, or slow down noticeably. You might see apps you didn't install, unexpected pop-ups that won't close, or data usage spikes when you're not actively using the phone. Text messages or emails from your contacts may mention messages you never sent. These signs don't always mean a virus — a full storage or a bad app update can cause the same symptoms — but they're worth investigating.

The most common entry point on phones is a malicious app. Check your installed apps by going to Settings, then Apps (or process Manager on older Android phones). Look for anything you don't recognize or don't remember downloading. Uninstall anything suspicious. On iPhone, go to Settings > General > iPhone Storage to see what's taking up space and what you actually use. If an app has a generic name like "Update" or "System" but isn't from Apple, that's a red flag.

Key Takeaways

  • Battery drain, unexpected heat, slowness, and unfamiliar apps are often the first signs of a problem, and checking these manually takes five minutes.
  • Built-in security scans on Android (Google Play Protect) and iPhone (on-device scanning) are free and run automatically, but they catch only known threats.
  • Uninstalling suspicious apps and keeping your phone's operating system updated prevent most infections better than any scan does.
  • Third-party antivirus apps on iPhone offer little real protection because Apple's system architecture blocks them from scanning deeply, but some Android users find them useful for peace of mind.
  • If your phone shows signs of compromise, a factory reset is the most reliable way to remove anything hidden, though it erases all data.

How to run Android's built-in virus scan

Android phones come with Google Play Protect, a built-in security scanner that runs automatically in the background. It checks apps you read from the Google Play Store and scans your phone periodically without you having to do anything. To see the results of the last scan or run one manually, open the Google Play Store app, tap your profile icon in the top right, then go to Manage apps and device > Manage > Security. You'll see a timestamp of the last scan and a green checkmark if no threats were found.

If Play Protect finds something, it will show you the app name and offer to uninstall it. Tap Remove and the app is gone. If you sideload apps (read them from outside the Play Store), Play Protect may not catch them, which is why sideloading from untrusted sources is the highest-risk behavior on Android. If you do sideload, scan the file with a tool like VirusTotal (virustotal.com) before installing it — upload the file and it will check it against dozens of antivirus engines.

How to check security on iPhone

iPhone's security model is different from Android. Apple's operating system doesn't allow apps — even antivirus apps — to scan your entire phone the way Android apps can. Instead, Apple does the scanning itself, on your device and in the background. You don't run a manual scan the way you would on Android. If Apple detects malware, it will notify you and guide you to remove it.

What you can do on iPhone is check for suspicious apps and review what permissions you've granted. Go to Settings > Privacy and look at each category — Camera, Microphone, Location, Photos, Contacts. Tap each one and remove access from any app that shouldn't need it. Then go to Settings > General > iPhone Storage and look at what's installed. Delete anything unfamiliar. If you're concerned about a specific app, delete it and reinstall it fresh from the App Store.

When to consider a third-party antivirus app

Third-party antivirus apps exist for both Android and iPhone, but they work very differently. On Android, apps like Bitdefender, Norton, and Kaspersky can scan your files and apps because Android's system allows it. On iPhone, apps labeled "antivirus" or "security" cannot actually scan your phone — Apple's restrictions prevent it. They can check for weak passwords or monitor if your data appears in known breaches, but they're not scanning for malware the way Android apps do. If you use iPhone, a third-party security app won't add real protection against viruses.

On Android, a third-party app may catch threats that Play Protect misses, but it also uses battery and storage space. Most security experts say Play Protect is sufficient for most people, especially if you only read from the Play Store and don't click suspicious links. A third-party app makes sense if you sideload frequently, use public Wi-Fi often, or want the reassurance of a second opinion — but it's not a replacement for keeping your operating system updated and being careful about what you install.

Why updates matter more than scans

The single most effective protection against viruses and malware is keeping your phone's operating system up to date. Every update patches security holes that hackers use to get in. A phone running an old version of Android or iOS is far more vulnerable than a phone with the latest version, even with antivirus software running. Check for updates by going to Settings > System > System Update on Android, or Settings > General > Software Update on iPhone. Turn on automatic updates if you can — both systems offer this option.

App updates matter too. Malware often spreads through outdated apps with known vulnerabilities. Go to the Google Play Store or App Store, tap your profile, and check for pending updates. Enable automatic app updates in the settings so you're not manually checking every week.

What to do if you think your phone is infected

If your phone shows multiple signs of infection — unfamiliar apps you can't find, constant crashes, severe battery drain, or messages from contacts saying you sent them things you didn't — start by uninstalling any suspicious apps and running a full scan with Play Protect (Android) or checking your app list carefully (iPhone). Restart your phone in Safe Mode, which disables third-party apps and may help you identify which app is causing the problem. On Android, hold the power button, then press and hold "Power off" until a Safe Mode option appears. On iPhone, restart the phone normally — there's no traditional Safe Mode, but a restart often clears temporary problems.

If the problem persists after uninstalling suspicious apps and restarting, a factory reset is the most reliable way to remove anything hidden. This erases all data on your phone, so back up what you need first — photos, contacts, messages — to cloud storage or a computer. After the reset, reinstall only the apps you actually use, and avoid whatever behavior led to the problem in the first place (clicking links in texts from unknown numbers, downloading apps from outside the official store, visiting risky websites).

How to avoid infection in the first place

Most phone infections come from three sources: malicious apps, phishing links in texts or emails, and compromised Wi-Fi networks. Avoid them by downloading apps only from the Google Play Store or Apple App Store, not from random websites or links in messages. Don't click links in text messages or emails from people you don't know, even if they claim to be from your bank or a delivery service — legitimate companies won't ask you to click a link to verify your account. If you're unsure, go directly to the company's website by typing the address yourself rather than clicking a link.

On public Wi-Fi, avoid logging into sensitive accounts like banking or email. If you must, use a VPN (Virtual Private Network) to encrypt your traffic — apps like ProtonVPN or Mullvad offer free options. Be skeptical of apps that ask for permissions they don't need — a flashlight app doesn't need access to your contacts or location. Review permissions when you install something new, and revoke them later if the app isn't using them.

Frequently Asked Questions

Can I get a virus just from visiting a website?

On modern phones, it's very difficult. iPhone's Safari browser and Android's Chrome are designed to isolate websites so they can't directly access your phone's files or install software. You're much more likely to get infected by clicking a link that takes you to a fake login page (phishing) or by downloading an app. Visiting a risky website alone is low-risk if you don't click anything.

Is it safe to use free antivirus apps?

Free antivirus apps on Android work, but they make money by selling your data or showing ads. If you use one, read the privacy policy first. On iPhone, free "antivirus" apps can't actually scan for viruses due to Apple's restrictions, so they're mostly marketing. If you want one for password checking or breach monitoring, that's a different tool than antivirus.

What does it mean if Google Play Protect says "device not certified"?

This usually means your phone is running a modified version of Android or has been rooted (jailbroken). It doesn't necessarily mean you have a virus, but it does mean Google can't verify the phone's security. If you didn't intentionally modify your phone, this is worth investigating — it could indicate someone else has access to it.

Will a factory reset remove all malware?

A factory reset removes almost all malware because it erases the entire operating system and reinstalls it fresh. The only exception is malware in the phone's firmware (the lowest level of software), which is extremely rare on consumer phones. For practical purposes, a factory reset is the nuclear option that solves the problem.

Do I need antivirus if I only use the official app stores?

Probably not. The official app stores have security screening, and Google Play Protect runs automatically on Android. The biggest risk factor is your own behavior — clicking suspicious links, downloading apps from outside the store, or using weak passwords. If you stick to the official stores and don't click random links, you're already doing most of what antivirus software does.