What’s the one device which is most valuable to you because of its everyday usefulness, and most vulnerable because of how much sensitive data it provides access to?

The obvious answer is your smartphone, and if that’s the case then you need to be proactive in securing it against cyber threats, and vigilant for any red flags that indicate a breach has occurred. So what can you do to defend it from hackers, and how can you tell if it is already compromised?

Stay away from phony websites

Getting to grips with how to spot phishing websites is a good move for all modern web users. Untrustworthy sites are used by crooks to infect the devices used to access them, so avoid them by visiting trusted sites directly and never giving away personal information on a site you don’t know to be legitimate.

You should also sidestep phishing emails, as these can contain malicious links or attachments which will cause chaos if downloaded.

Use a password-protected lock screen

You should never leave your phone unguarded in public, but if you do it’s best to have a lock screen in place that only you know the password or access code to open.

Using biometric scanning, such as your fingerprint, can also bolster phone security when out and about. If you’re choosing a password, make sure it’s a strong one and not easily guessable.

Warning sign: hearing strange noises while you’re on a phone call

Becoming familiar with how to tell if someone is listening to your phone calls is sensible as this is one of the indicatives of suspicious activity.

If there are weird, unexplained, and unusual sounds in the background of your calls which are not normally there, you can deduce that a third party is potentially interfering, and could be listening in live, or even recording your conversations for their own underhanded purposes.

Warning sign: a spike in data use

A hacked phone is only useful to the attackers if they can steal data from it, and this results in increases in network usage which are impossible to disguise.

Checking up on how much data you are using is easy in the settings menu of most mobiles, and you might even get notified by your network provider if you’re using more data than normal. Of course, you need to have a sense of what your typical data usage patterns are to pinpoint anomalies, so it’s worth looking into even if you don’t think your phone has been breached.

Warning sign: poor interface responsiveness and slow app performance

For the most part, modern mobile phones pack enough processing power to handle everyday interactions and tasks swiftly, without much slowdown or sluggishness.

If your device is comparatively new, and it suddenly starts to perform well below its normal level, then something is definitely amiss.

This could be as simple as an issue of having too many apps open in the background. But if you close all potential culprits and performance still won’t speed up, then malicious software might well be the cause.

Warning sign: battery life is suddenly and inexplicably awful

No battery lasts forever, but you should still be able to get a few years of use out of a typical smartphone cell.

If, on the other hand, you experience rapid draining of the battery without a clear cause, this can signal that something’s afoot behind the scenes, usually in the form of a security breach.

So stay on the lookout and always check up on suspicious issues we’ve mentioned, rather than letting them go unresolved.