How to tell if your phone has been hacked (and what to do)

A hacked phone rarely announces itself. There’s no skull-and-crossbones — just a collection of small “off” behaviours that are easy to explain away individually. The trick is knowing which symptoms actually matter and which are just an ageing battery. Here’s how to read them honestly.

Signs worth paying attention to

A few things are genuinely worth investigating when they appear suddenly and together. Battery draining much faster than it did last month, or the phone running warm when you’re not using it, can mean something is working in the background. A jump in data usage you can’t account for is a classic sign of software quietly sending information out. Pop-ups appearing outside any app, apps you don’t remember installing, or your battery and data both spiking at once all deserve a closer look.

The key word is “suddenly”. Phones slow down and batteries age gradually — that’s normal. It’s the abrupt change, with no obvious cause, that’s the signal.

Things that are usually nothing

Don’t spiral. An older phone getting slower, the battery not lasting like it used to, the occasional app crash, or a hot phone while gaming or navigating are all normal wear, not evidence of a breach. One weird ad on a dodgy website isn’t a hack either. Look for a cluster of the serious signs above before you assume the worst.

What to do if you’re worried

Work through it in order. Update your phone’s operating system and all your apps — updates patch the holes most attacks rely on. Delete any app you don’t recognise or don’t remember installing. Run a scan with a reputable security app. Then change the passwords for your important accounts — email first, since it’s the key to everything else — ideally from a different, trusted device. If things are clearly wrong and won’t clear up, a factory reset (after backing up your photos and files) is the reliable reset button.

Reducing the odds next time

Most phone compromises trace back to a handful of habits: installing apps from outside the official stores, tapping links in phishing messages, or logging in over hostile Wi-Fi. Stick to official app stores, be sceptical of links you didn’t expect — our guide to spotting phishing emails helps — and keep a VPN on when you’re on networks you don’t control, so your logins can’t be intercepted in transit. None of it is foolproof, but together it closes the doors attackers use most.