A phone that suddenly feels “off” is unsettling — and it is one of the most common worries readers write to us about. The good news is that a genuinely compromised phone almost always leaves clues. The team has pulled together the warning signs worth knowing, how to confirm whether something is actually wrong, and exactly what to do if it is.
The warning signs your phone may be hacked
No single symptom proves a phone has been hacked — modern phones get warm and chew through battery for plenty of innocent reasons. But when several of these show up together, it is worth taking seriously.
1. The battery drains far faster than usual
Malicious software runs in the background, and background activity costs power. If your battery life has fallen off a cliff with no change to how you use the phone — and no recent OS update — that is a flag. (If your battery has simply aged, our guide on getting more from your devices and the battery tips below will help more than a virus scan.)
2. The phone runs hot when you are not using it
A handset that is warm in your pocket while idle is doing work you did not ask for. Occasional heat during gaming or charging is normal; constant warmth is not.
3. Spikes in mobile data use
Spyware and adware “phone home” — sending data to a server somewhere. Check your data usage by app in Settings. An unfamiliar app, or a familiar one using wildly more data than it should, deserves a closer look.
4. Pop-ups, new apps and changed settings
Aggressive pop-ups outside the browser, apps you never installed, or settings that change themselves are classic signs of a compromised device. Browser home pages that reset to something unfamiliar belong on this list too.
5. Friends receive messages you never sent
If contacts mention texts, emails or social posts from you that you did not write, malware may be using your accounts to spread itself. This is one of the clearest signals that something is genuinely wrong.
6. Strange charges or account activity
Unexpected charges, premium-SMS subscriptions, or login alerts from places you have never been are red flags. We have seen how quickly stolen credentials get abused — the Formspring breach is a reminder that exposed passwords rarely sit idle for long.
How phones actually get compromised
Understanding the “how” makes prevention far easier. The realistic threats are:
- Malicious apps — usually side-loaded from outside the official stores, occasionally slipping through them.
- Phishing links — a text or email that takes you to a fake login page and harvests your details.
- Dodgy public Wi-Fi — unsecured networks where an attacker can intercept traffic.
- Reused passwords — one breached site exposes a password you also used somewhere important. Breaches like Australia’s Early Warning Network incident show how a single weak point cascades.
- Physical access — someone with your unlocked phone for a few minutes can install monitoring software.
Notice what is missing: dramatic “remote hacking” of a fully updated phone is rare. Almost every real-world compromise needs you to tap, install or reuse something.
What attackers are actually after
It helps to remember that phone compromise is rarely personal — it is a numbers game. Attackers want things they can turn into money or leverage: your banking and payment logins, your email (the master key that resets every other account), contact lists to spread the same scam wider, and any saved passwords or photos worth holding to ransom. Some malware simply hijacks your phone’s processing power or pushes ad fraud in the background. Knowing the goal is useful, because it tells you what to protect hardest — your email and banking access first, everything else second.
How to check whether your phone is really compromised
Before assuming the worst, work through these steps calmly.
Review your installed apps. Scroll the full list — not just the home screen. Anything you do not recognise, research before you do anything else, then remove it.
Check app permissions. In Settings, look at which apps can access your camera, microphone, location and messages. A simple game with microphone access makes no sense — revoke it.
Look at battery and data by app. Both iOS and Android break usage down per app. The culprit often sits right at the top of one of those lists.
Check for unknown profiles or device admins. On iOS, look under VPN & Device Management; on Android, under Security for device-admin apps. Anything unexpected there is a serious concern.
Run a reputable mobile security scan. A well-reviewed security app from the official store can confirm or rule out known malware.
What to do if your phone has been hacked
If the signs point to a real compromise, act in this order.
- Get offline. Turn on aeroplane mode to cut the malware off from the internet while you work.
- Delete suspicious apps. Remove anything you identified as untrusted.
- Change your important passwords — from a different, trusted device. Start with email, then banking, then social accounts. Never reuse a password across sites; weak credential hygiene is exactly how incidents like the Google Drive and Mac trojan campaign spread.
- Turn on two-factor authentication everywhere it is offered. Even a stolen password is far less useful without the second step.
- Update your operating system. Updates close the security holes malware relies on.
- If problems persist, back up your data and factory reset. A clean reinstall is the only way to be certain stubborn malware is gone. Restore apps individually rather than from a full backup that might carry the problem back.
- Tell your bank and watch your accounts if any financial details were on the device.
If money has been taken or you have been scammed, report it to the Australian authorities through the Australian Cyber Security Centre’s ReportCyber service — it helps you and helps track the people responsible.
How to keep it from happening again
Prevention is genuinely straightforward, and it is mostly habit:
- Install apps only from the official App Store or Google Play, and check reviews and permissions first.
- Keep your operating system and apps updated — turn on automatic updates.
- Use a unique, strong password for every account, ideally through a password manager.
- Turn on two-factor authentication on every account that supports it.
- Never tap links in unexpected texts or emails, even ones that look official.
- Avoid sensitive logins on public Wi-Fi, or use a trusted VPN when you must.
- Lock your phone with a strong passcode plus biometrics — physical access matters.
The Australian Government’s device security guidance is a solid, jargon-free reference if you want to go further.
iPhone or Android — does it change the risk?
Both platforms are far more secure than their reputations suggest, but they fail in slightly different ways. iOS is a tighter, more locked-down system, so the realistic threat there is phishing and account takeover rather than rogue apps — which is why even Apple’s ecosystem has its weak points, as we explored in our look at Apple TV security. Android’s openness is a genuine strength for users who want control, but side-loading apps from outside Google Play is where most Android malware gets its foothold. The practical takeaway is the same on either platform: stick to official stores, keep the system updated, and the device itself is rarely the weak link — you and your passwords are.
Frequently asked questions
Can someone hack my phone just by calling or texting me? Simply answering a call cannot install malware. The danger is in what you do next — tapping a link, calling back a number, or following instructions in the message. Treat unexpected contact with healthy suspicion.
Will a factory reset definitely remove malware? In almost every case, yes — a reset wipes the apps and data malware lives in. The catch is restoring from a full backup made while infected, which can reintroduce the problem. Restore apps and files selectively instead.
Do I need a paid antivirus app for my phone? Not necessarily. Built-in protections on iOS and Android are strong, and a reputable free scanner is enough for most people. Good habits matter far more than any single app.
How can I tell if someone installed spyware to track me? Look for the signs above — battery drain, heat, data spikes — plus any unfamiliar device-admin app or configuration profile. If you suspect stalkerware and your safety is at risk, a factory reset and new passwords (set from another device) are the safest path.
The bottom line
Most phones that “feel hacked” are simply old, full, or in need of an update — but the warning signs above are real, and worth knowing. If several line up, work through the checks calmly, clean the device properly, and lock down your accounts. A modern phone, kept updated and paired with good password habits, is a genuinely hard target. Stay a little sceptical of unexpected links and you have already won most of the battle.
