How to Know If Your Phone Is Hacked: Signs and What to Do
Learn the warning signs of a hacked phone, how to check your device and accounts, and what to do if you find suspicious activity.
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What to Do If Your Phone Is Hacked
How to Protect Your Phone
Your phone may hold your banking apps, email, photos, saved passwords and two-factor authentication codes. So when it suddenly behaves differently, the first question is not whether it has been hacked, but what changed and whether there is evidence of unauthorised access.
Battery drain, overheating, unusual data usage or a new app can have completely normal causes. The more useful clues are things such as an unknown app, an unfamiliar device signed into your account, messages you did not send or a password change you did not make.
This guide shows you how to check your phone, apps and accounts step by step, with separate checks for iPhone and Android.
At a Glance: What to Check
Phone Behavior Warning Signs & What to Check
A quick troubleshooting guide to diagnose unusual device activity and performance issues.
| What you notice | Check this first |
|---|---|
| Battery drains quickly | Battery usage by app |
| Phone gets hot while idle | Background apps and recent activity |
| Unknown app appears | App details and permissions |
| Data usage jumps | Data usage by app |
| Unknown account activity | Signed-in devices and security alerts |
| Camera or mic activates unexpectedly | App permissions |
| Messages or calls you didn't make | Account and communication history |
| Strange pop-ups or redirects | Recently installed apps and browser settings |
Quick takeaway: One unusual symptom does not necessarily mean your phone has been hacked. Look for several unexplained changes and check your device, apps and accounts before assuming your phone has been compromised.
Not Every Strange Phone Problem Means a Hack
A slow phone, warm battery or sudden drop in battery life is not enough to confirm that someone has accessed your device. Charging, poor network coverage, background syncing, an ageing battery and demanding apps can all produce similar symptoms.
What matters is whether you can connect the problem to something you did not authorise.
Phone Symptoms: Everyday Causes vs. More Concerning Signs
A side-by-side comparison to help differentiate normal device behavior from potential security red flags.
| Symptom | Possible everyday cause | More concerning when |
|---|---|---|
| Battery drain | Ageing battery, gaming, streaming | Unknown app is also using high battery |
| Phone heating | Charging, gaming, poor signal | It repeatedly heats up while idle |
| High data usage | Backup, streaming, updates | An unfamiliar app is responsible |
| Pop-ups | Browser notifications | They appear across different apps |
| OTP you didn't request | Someone attempting a login | Account details also change |
| Slow performance | Heavy apps, low storage | It starts after an unknown app is installed |
How Do You Know If Your Phone Has Been Hacked?
There is no single sign that proves a phone has been hacked. Instead, look for several changes that you cannot explain and then investigate them through your device’s security and account settings.
Here are some of the most common warning signs.
Your Battery Is Draining Faster Than Usual
If your battery suddenly lasts much less than it normally does, check which apps are responsible before assuming there is a security problem. Streaming, navigation, gaming, poor signal and an ageing battery can all increase power use.
Open Battery settings and look for an unfamiliar app near the top of the list. The concern is higher if the battery change appeared at the same time as a new app, unusual data usage or other account activity.
Your Phone Is Getting Hot Without Heavy Use
A phone that stays warm while sitting unused deserves a closer look, especially if you cannot connect it to charging, navigation, gaming or another demanding task.
Check which applications are running in the background and whether a recent installation or update coincided with the problem.
A slow or hot phone does not automatically mean it has been hacked. Performance can also change because of thermal throttling, background processes or demanding workloads. Our guide to smartphone throttling and why phones slow down during heavy use explains why performance can drop when a device gets too hot.
You Notice Apps You Do Not Recognise
An unfamiliar application is one of the more useful things to investigate.
Open your complete app list and look for anything you do not remember installing. Pay particular attention to applications with access to sensitive permissions such as the camera, microphone, contacts, SMS, accessibility features or location.
Do not immediately assume every unfamiliar app is malicious. Some system components may have names you do not recognise. Search for the app’s official name before removing anything essential to the operating system.
Your Mobile Data Usage Suddenly Increases
Unexpected data consumption can sometimes reveal an application working in the background.
Check your phone’s mobile-data settings and identify which applications have used the most data. If one unfamiliar application has unusually high usage, investigate it.
There may be an ordinary explanation, such as automatic backups, video streaming or an app downloading a large update. The important point is to identify the cause rather than treating high data usage alone as proof of hacking.
Strange Pop-Ups or Notifications Appear
Repeated pop-ups, browser redirects or security warnings that appear outside normal apps can be a sign that something needs attention.
Avoid clicking suspicious messages that tell you to install software, enter passwords or make payments. Instead, close the page and investigate the app or browser responsible.
On Android, Google says Play Protect checks apps for potentially harmful behaviour and can warn about, disable or remove harmful applications.
You Receive Two-Factor Authentication Codes You Did Not Request
An unexpected verification code can be an important warning.
It may mean someone is attempting to sign in to an account using your credentials. It does not necessarily mean your phone itself has been hacked.
If you receive an unexpected code, do not share it with anyone. Instead, open the relevant service directly, check recent account activity and change your password if necessary.
Apple lists unrequested two-factor authentication codes, unfamiliar account activity and unknown devices among signs that an Apple Account may have been compromised.
You See Calls or Messages You Did Not Send
Check your messages, call history and other communication apps if you notice activity you do not recognise.
Unfamiliar messages may indicate that someone accessed your account or device. They could also result from another person having access to an account signed in on another device.
Look at your account sessions and the phone itself before deciding what happened.
Voice-based scams are also becoming harder to recognise, including AI-powered voice scams that imitate people you know.
Your Camera or Microphone Behaves Unexpectedly
Modern phones provide indicators when applications access sensitive hardware such as the camera or microphone.
If you repeatedly see an indicator when you are not intentionally using a feature that needs it, check which application recently had access.
Go to your privacy settings and review camera and microphone permissions. Remove access from apps that do not need it.
This is more useful than assuming that an unusual camera indicator automatically means somebody is watching you.
You Suddenly Lose Access to an Account
A password that stops working, an unexpected password-reset notification or an unfamiliar device appearing in your account can be more significant than general phone performance problems.
If this happens, secure the affected account immediately.
For Apple Accounts, Apple recommends changing the password, checking account information and removing unfamiliar devices if you believe someone has gained access.
How to Check If Your Phone Is Hacked
If something on your phone seems wrong, work through these checks in order. Start with the device itself, then move to your accounts.
1. Review Your Installed Apps
Open the complete list of applications installed on your phone.
Look for:
- Apps you do not remember installing
- Recently installed apps you did not authorise
- Apps with suspicious names
- Apps requesting permissions they do not appear to need
Before deleting a system component, verify what it does.
2. Review App Permissions
Check which applications can access your:
- Camera
- Microphone
- Location
- Contacts
- Photos
- Files
- SMS
- Phone
- Accessibility features
Remove unnecessary permissions where appropriate.
An app having a permission does not mean it is malicious, but an application requesting sensitive access without a clear reason deserves investigation.
3. Check Battery and Data Usage
Look at battery and mobile-data usage by application.
Compare the results with your normal habits.
If a little-used app is consuming unusually large amounts of battery or data, investigate it before continuing to use it.
4. Review Your Account Activity
Check the security pages of your major accounts, including your email, Apple Account or Google Account.
Look for:
- Unknown devices
- Unfamiliar login locations
- Password changes you did not make
- New recovery information
- Unusual purchases
- Unexpected security notifications
This can help distinguish a hacked phone from a compromised online account.
5. Check for Software Updates
Install available operating-system and security updates.
Updates can contain important security fixes, so running an outdated version can leave known vulnerabilities unpatched.
6. Run Built-In Security Checks
Android users should check Google Play Protect. Google says Play Protect periodically scans installed apps and can warn users about potentially harmful applications.
If you use an iPhone, Apple’s built-in security and privacy controls can help you review account access, connected devices and information shared with apps.
How to Check If Your iPhone Has Been Hacked
If you use an iPhone, start with your Apple Account and privacy settings. Apple’s Safety Check is available on iPhones running iOS 16 or later. It lets you review who has access to your information, check devices connected to your Apple Account, reset certain privacy permissions and change security credentials. You can find it under Settings > Privacy & Security > Safety Check.
You should also check:
- Devices connected to your Apple Account
- Recently installed applications
- App privacy permissions
- Battery usage
- Cellular-data usage
- Unexpected two-factor authentication codes
- Unfamiliar purchases
- Account recovery information
If you find an unfamiliar device connected to your Apple Account, remove it and change your password.
Apple also recommends checking your trusted devices and account information if you believe your Apple Account has been compromised.
Remember that unusual battery drain or a warm device does not by itself prove that an iPhone has been hacked.
How to Check If Your Android Phone Has Been Hacked
Android settings vary between manufacturers, so the exact menu names can differ between Samsung, Google Pixel, OnePlus and other devices.
Start with your installed apps and permissions.
Then open the Google Play Store and check Google Play Protect. It checks apps and devices for potentially harmful behaviour, including apps installed from sources outside Google Play. It can warn you about harmful apps and, in some cases, disable or remove them.
Also check:
- Google Account devices
- App permissions
- Accessibility access
- Battery usage
- Mobile-data usage
- Device administrator access
- Recently installed apps
- Android and security updates
If you installed an app from outside Google Play and then noticed suspicious behaviour, pay particular attention to that application.
Google recommends keeping Play Protect enabled and installing apps from trusted sources because applications obtained from unknown sources can create security and privacy risks.
Can Someone Hack Your Phone Camera?
Yes, malicious software or unauthorised access can create privacy risks, but a camera indicator or a warm phone does not automatically mean someone is remotely watching you.
If you are concerned, check which applications have camera permission.
On iPhone, review the relevant privacy controls and use Safety Check when appropriate. On Android, review the camera permission list in your privacy settings. Pay particular attention to applications that:
- You do not recognise
- Do not need camera access for their main function
- Were installed shortly before the problem appeared
- Have other suspicious permissions
If you identify an application that should not have camera access, remove the permission and investigate the application further.
Can Someone Hack Your Phone Number?
Your phone number can be compromised without the entire phone being hacked.
One example is a SIM-swap attack. In this situation, a scammer attempts to persuade a mobile carrier to transfer your number to another SIM. The attacker can then potentially receive calls and SMS messages intended for you.
A sudden loss of mobile service, followed by an unexpected carrier notification or account activity, can be a warning sign.
The US Federal Trade Commission explains that an unexpected loss of calls, texts and mobile data, especially alongside a notification that your SIM has been activated on another device, can indicate a SIM-swap scam.
If you suspect this has happened, contact your mobile carrier immediately and ask them to secure your number. Then review important accounts that rely on SMS-based verification.
Is Your Phone Hacked or Is Your Account at Risk?
Security Warning Signs & What Could Be Affected
A quick reference guide linking suspicious device events to vulnerable assets and accounts.
| What happened | What could be affected |
|---|---|
| Unknown app installed | Phone |
| App has unnecessary sensitive permissions | Phone/app access |
| Unknown device signed into Google/Apple | Account |
| Password changed without you | Account |
| Unexpected OTP | Account login attempt |
| SIM suddenly stops working | Mobile number |
| Unrecognised bank transaction | Financial account |
What Should You Do If Your Phone Has Been Hacked?
If your checks reveal several suspicious signs, focus on securing your accounts and device rather than continuing to investigate indefinitely.
- 1. Change Important Passwords
Start with your primary email account, Apple Account or Google Account, banking accounts and other services containing sensitive information.
Use a different, strong password for each important account.
If you suspect that your phone itself is compromised, consider changing passwords from a different trusted device.
- 2. Enable Two-Factor Authentication
Turn on two-factor authentication wherever it is available. For sensitive accounts, consider authentication methods that do not rely entirely on SMS when a stronger option is available. CISA notes that phishing and SIM swapping can be used to target authentication credentials, which is why stronger phishing-resistant authentication can provide additional protection. For a broader look at phishing, SIM swaps, fake calls and other online scams, see our guide to common cyber fraud and scam tactics.
- 3. Remove Suspicious Applications
Uninstall applications you have verified as unnecessary or suspicious.
If an app refuses to uninstall or keeps returning after removal, investigate the permissions and device-management settings involved rather than repeatedly reinstalling it.
- 4. Update Your Phone
Install the latest available operating-system and security updates.
This is especially important if the device has been running an outdated version for an extended period.
- 5. Check Your Financial Accounts
If you believe someone may have accessed your phone, email or authentication codes, review your bank, card, payment and shopping accounts for unfamiliar activity. For anything you do not recognise, contact the relevant provider directly through its official website or app.
- 6. Contact Your Mobile Carrier
If your phone suddenly loses cellular service or you suspect a SIM swap, contact your carrier as soon as possible. Ask them to check whether any recent SIM replacement, number transfer or account change was requested. - 7. Consider a Factory Reset
A factory reset should not be the first response to every unusual phone problem.
However, if you have strong reasons to believe malicious software remains on the device and other steps have not solved the problem, a factory reset may be appropriate. Back up important information first and make sure you know the account credentials required to set the phone up again.
How to Protect Your Phone From Being Hacked
Once you know how to know if your phone is hacked, prevention becomes the next priority.
Keep your operating system and applications updated. Install software from official or trusted sources, and review permissions regularly.
Use a strong screen lock and unique passwords for important accounts. Enable two-factor authentication, and avoid entering passwords or verification codes after following unexpected links.
Be particularly careful with messages claiming that your bank, email provider, delivery company or mobile carrier needs immediate action. Open the official app or website yourself instead of following an unfamiliar link.
You should also maintain regular backups of important photos, documents and other data. A backup cannot prevent a security incident, but it can make recovery much easier.
For iPhone users, Apple recommends keeping software updated, using a unique passcode, securing the Apple Account and enabling two-factor authentication.
Frequently Asked Questions
Quick Answers to Common Questions
No single symptom confirms that a phone has been hacked. Look for several unexplained changes, especially unknown apps, unfamiliar account devices, unauthorised messages or unexpected password changes. Battery drain or overheating alone is not enough to confirm a compromise.
Review installed apps, permissions, battery and data usage, account sessions and security settings. Android users can also run Google Play Protect, while iPhone users can use Apple’s available security and privacy controls.
It is possible for malicious software or unauthorised account access to go unnoticed for some time. Regularly checking installed apps, permissions, account devices and security alerts can help you spot problems earlier.
Malicious software can abuse camera permissions, but a camera indicator alone doesn’t prove that someone is accessing the camera. Check which apps have camera permission and remove access where it isn’t needed.
A phone number can be taken over through methods such as SIM swapping even when the physical phone itself has not been compromised. Sudden loss of cellular service combined with unexpected carrier activity can be a warning sign.
Check your Apple Account for unfamiliar devices, review app permissions and use Safety Check on supported iPhones. Unexpected two-factor authentication codes, account changes and unknown devices can be signs that your Apple Account has been compromised.
Review installed applications, permissions, battery and data usage, Google Account activity and security settings. Run Google Play Protect to check for potentially harmful applications and install available security updates.
Conclusion
A strange phone symptom is a reason to check, not automatic proof of a hack. Start with the things you can verify: installed apps, permissions, account devices, security alerts and recent activity.
If you find unauthorised access, secure the affected account first, remove anything you don’t trust, and update the device. If your mobile service suddenly stops, contact your carrier as well. The goal is to identify what has actually been compromised and then take the smallest effective step to secure it.