Signs your phone might be infected

Your phone shows signs of infection through behavior changes you can notice without special tools. The most common indicators are a sudden slowdown when opening apps or switching between them, unexpected battery drain even when you are not using the device, or data usage spikes that do not match your normal patterns. Check your phone bill or your carrier's app to see if data consumption jumped without explanation.

Other warning signs include apps crashing repeatedly, your phone getting hot during normal use, pop-up ads appearing on your home screen or in places they should not, and text messages or calls from people saying they received strange messages from your number that you did not send. If your phone restarts on its own or gets stuck on the startup screen, that can also point to malware, though it may also be a hardware or software glitch unrelated to infection.

One specific indicator is if your phone bill suddenly includes charges for services you did not sign up for, or if your contacts report receiving spam or phishing messages from your number. Malware sometimes uses your phone to send messages to your contact list without your knowledge.

Key Takeaways

  • Battery drain, unexpected data usage, app crashes, and random restarts are the most common signs of phone malware, though they can also result from software bugs or hardware problems.
  • Your phone's built-in security scanner — Google Play Protect on Android or the security features in iOS — can scan for known malware without you installing anything extra.
  • Uninstalling recently added apps, clearing your cache and app data, and restarting in safe mode are the first steps to take before assuming you need professional help.
  • If your phone is heavily infected, a factory reset is the most reliable way to remove malware, but it erases all data, so back up important files first.
  • Preventing infection is simpler than removing it: only read apps from official stores, keep your operating system updated, and avoid clicking links in unexpected text messages or emails.

How to run a built-in security scan on Android

Android phones come with Google Play Protect, a built-in scanner that checks for known malware. Open the Google Play Store app, tap your profile icon in the top right corner, then tap "Manage apps and device." Go to the "Manage" tab and look for "Security." Tap "Run security scan" and wait for it to finish — this usually takes a few minutes.

Google Play Protect scans apps you have already installed and flags anything it recognizes as malware or spyware. If it finds something, it will show you the app name and offer to uninstall it. Tap "Remove" and the app will be deleted from your phone. This scan does not catch every possible threat, especially newer malware that has not been catalogued yet, but it catches the most common ones.

If you want a second opinion, you can also read a reputable third-party scanner like Malwarebytes or Avast from the Play Store, run a scan, and then uninstall it afterward. Do not keep multiple security apps running at the same time — they can conflict with each other and slow your phone down.

How to run a security scan on iPhone

iPhones do not have a dedicated malware scanner app because iOS is designed to prevent malware from running in the first place. Apple's App Store has stricter review rules than Google Play, and iOS apps run in isolated containers that prevent them from accessing other apps' data or system functions. However, you can still check for signs of compromise.

Go to Settings, then Battery, and look at which apps are using the most power. If an app you rarely use is draining significant battery, that can be a sign of malicious activity. You can also check Settings > Privacy to see which apps have requested access to your location, contacts, photos, or microphone — if an app you do not recognize has these permissions, that is suspicious.

If you suspect infection, the most reliable step is to restart your phone in recovery mode and restore from a backup made before you noticed the problem. This is more involved than an Android reset, so contact Apple Support or visit an Apple Store if you are not comfortable doing this yourself.

Uninstalling suspicious apps and clearing cache

Before doing a full reset, try removing apps you do not recognize or recently installed. Go to Settings > Apps (Android) or Settings > General > iPhone Storage (iPhone), look through the list, and uninstall anything unfamiliar or anything you installed around the time the problems started. Malware often disguises itself with a generic name or hides among legitimate-looking apps.

On Android, also clear the cache and data for apps that are misbehaving. Go to Settings > Apps, tap the app, then tap "Storage" and select "Clear Cache" and "Clear Data." This removes temporary files and resets the app to its default state, which can remove some types of malware that store themselves in app data. On iPhone, you can offload an app (Settings > General > iPhone Storage, tap the app, then "Offload App") which removes it but keeps your data, then reinstall it fresh from the App Store.

After uninstalling or clearing data, restart your phone and monitor whether the problems continue. If battery drain and crashes stop, you have likely found the culprit. If the problems persist, move to the next step.

Restarting in safe mode to isolate the problem

Safe mode loads only the essential system apps and disables all third-party apps temporarily. If your phone runs smoothly in safe mode but has problems in normal mode, that confirms a third-party app is causing the issue. On Android, press and hold the power button, then press and hold "Power off" until a menu appears asking about safe mode. Tap "Safe Mode" and your phone will restart.

Once in safe mode, use your phone normally for a few minutes. If the slowness, crashes, or battery drain disappear, you know the problem is an installed app, not the operating system itself. Go back to Settings > Apps and uninstall apps one at a time, restarting in normal mode after each removal, until the problem stops. This narrows down which app is responsible.

iPhones do not have a traditional safe mode, but you can force-restart your phone by pressing and quickly releasing the volume up button, pressing and quickly releasing the volume down button, then pressing and holding the side button until the Apple logo appears. This clears temporary memory and can sometimes resolve malware-related crashes, though it is less diagnostic than Android's safe mode.

Performing a factory reset as a last resort

If scanning, uninstalling apps, and safe mode do not resolve the problem, a factory reset is the most reliable way to remove malware. This erases everything on your phone and returns it to the state it was in when you first bought it, so back up your important photos, contacts, and documents first. On Android, go to Settings > System > Reset Options > Erase All Data, or Settings > General > Reset > Erase All Content and Settings on iPhone.

After the reset completes, your phone will restart and ask you to set it up again. Sign in with your Google account (Android) or Apple ID (iPhone), and restore from your backup. Only restore from a backup made before you noticed the infection — if you restore from a backup made after the malware arrived, you may restore the malware along with your data.

If you do not have a clean backup, set up your phone as new and reinstall only the apps you actually use. This is more time-consuming but guarantees you are not restoring malware. After setup, run a security scan again to confirm your phone is clean.

Preventing infection in the first place

The easiest protection is to read apps only from the official App Store (iPhone) or Google Play Store (Android). Third-party app stores have weaker security reviews and are common sources of malware. Even in official stores, stick to apps from well-known developers with many reviews and high ratings.

Keep your phone's operating system updated. Go to Settings > System > System Update (Android) or Settings > General > Software Update (iPhone) and install updates as soon as they are available. These updates patch security holes that malware exploits. Also turn on automatic updates if your phone offers that option.

Do not click links in text messages or emails from unknown senders, even if they claim to be from your bank or a delivery service. Malware often spreads through phishing links that look legitimate. If you receive a suspicious message from someone you know, contact them through another method to confirm they actually sent it. Be cautious with public Wi-Fi networks — use a VPN if you are accessing sensitive accounts on public Wi-Fi.

Frequently Asked Questions

Can malware on my phone steal my passwords and banking information?

Yes, some malware can capture passwords and financial data, especially if it has permission to access your keyboard input or screen. This is why running a security scan and removing suspicious apps quickly matters. If you suspect your banking information was compromised, contact your bank when ready and change your passwords from a clean device.

Will my phone work normally after I remove the malware?

Usually yes, but it depends on how long the malware was active and how much damage it caused. If you caught it early and removed it through scanning or uninstalling the bad app, your phone should return to normal speed. If the malware corrupted system files, a factory reset may be necessary to fully restore performance.

Is it safe to use my phone while it might be infected?

Avoid entering passwords, banking information, or credit card numbers until you have scanned and confirmed your phone is clean. Browsing the web and using messaging apps is generally lower risk, but malware can still capture sensitive data. The sooner you run a scan, the better.

What if Google Play Protect or my security scan finds nothing but my phone still has problems?

Not all malware is detected by built-in scanners, especially very new threats. Try uninstalling recently added apps, clearing cache, and restarting in safe mode. If problems persist after those steps, a factory reset is your most reliable option. If the problems continue even after a factory reset, the issue may be a hardware problem or a legitimate software bug rather than malware.

Do I need to pay for antivirus software on my phone?

No. Google Play Protect and iOS's built-in protections are free and sufficient for most users. Paid antivirus apps offer extra features like VPN or call filtering, but they are not necessary for basic malware protection. If you do install a paid app, uninstall it after scanning — do not keep it running permanently, as it drains battery.