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How we test mobile security apps

By Oli McKean

Our in-depth tests of the latest mobile security apps reveal which you can rely on to protect your phone or tablet from malware, and in the event that your device is stolen. 

Put us to the test

Our Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.

Just want to know which mobile security apps are the best? Head straight to our Best Buy mobile security apps.

Have a think about all the data you've got stored on your smartphone or tablet: phone numbers, addresses and website logins, plus private emails, messages and photos - and perhaps even online banking details. 

Then think about how you'd feel if a criminal was able to access all that data, which could be used to spam or send viruses to your friends and family, hack your social media accounts, read your emails and messages, or even spend your money using your account or card details. 

Whether you pay for a security app or get free antivirus protection for your smartphone or tablet, you’ll want peace of mind that the one you’ve chosen will keep it free from viruses and shielded from scams.

Mobile security firms claim that their apps offer brilliant protection from these digital nasties - but our independent testing regularly finds that many such claims fall short.

We've reviewed more than 20 of the most popular mobile security apps that you can find in the main app stores. You'll be able to trust our Best Buys to give you the best protection from viruses and scams - while the worst on test achieved a dismal score of just 43%, meaning minimal protection.

What makes a Best Buy mobile security app?

Every security app we review tackles an assault course of tests and trials to make sure that it’s worth downloading, all geared towards answering questions such as:

  • Will it protect you from malware, viruses and website scams?
  • Will the app help you avoid scams in the first place?
  • Will it help you find or wipe a lost or stolen device?
  • Is the app easy to use?
  • Crucially, should you download it?

Head to our mobile security app reviews or read on to find out more about how our mobile security app testing works.

Will it protect my device from malware?

We unleash a barrage of old and new viruses on our test device and scrutinise how well the security app deals with the attack. This is to ensure we only recommend the apps that offer good basic protection against day-to-day threats, and call out those that lack conviction and leave us without confidence.

Of course, you want to be notified if the security app finds anything untoward, but it will lose marks if the warnings contain hard-to-understand jargon or unnecessary scaremongering.

We also check whether the mobile security app scans for malware as it tries to access a device. Those that do this proactively get a thumbs-up from us, while we're less impressed when apps only spot a problem after you've manually initiated a scan.

Will the security app help me avoid scams?

We've all read the stories about people inadvertently clicking a link that purports to be from their bank, then having their bank accounts drained as they give away their password details to a scammer. These 'phishing' threats are all too real, which is why we make the security apps prove they can recognise a scam when they see one.

Some apps with anti-phishing claims completely miss the boat

Security apps with an anti-phishing feature are subjected to more than 25 scam webpages, emails and text messages to see if they’re flagged - with a few genuine ones thrown in to make sure that these pass through without difficulty. We then click on any dodgy-looking links to see whether the security app stops us from proceeding to these dangerous websites that are designed to infect machines or steal your data.

We've found mobile security apps that are defiantly intolerant of scams. But we've also found some apps with anti-phishing claims that completely miss the mark.

Can I recover a lost device?

It’s a typical worst-case scenario: your phone or tablet has been lost or stolen, but you have no idea where to start looking for it, or even how to reclaim your device. This is where theft-recovery tools can come in handy.

We test each security app’s remote location feature - which identifies and tracks the phone or tablet remotely via a computer - by placing our test device 500 metres away from the point of testing to measure its accuracy.

We also see if the remote wipe tool is effective. This lets you send a command to a missing phone or tablet and delete your private data. We look at how easy the feature is to set up, what data is wiped from the device and whether the data can be re-installed on another phone or tablet afterwards.

Is the security app easy to use?

Even if a downloaded security app is ruthless in its annihilation of virus and phishing email threats, it will only be a Best Buy if it’s not a hassle to use, too.

We buy and install each mobile security app on a ‘fresh’ phone and tablet, and rate this process. We look out for complications and attempts to upsell you more products. We then carefully rate the initial app set-up process and the first scan, looking to see whether it's easy for a beginner to get going.

72%The score a security app needs to earn to be considered a Which? Best Buy

Should I download it?

All the results are carefully analysed so that the highs and lows of every security app are revealed. If there's a fault, we'll purchase a new version of the app or contact the developer to see whether it’s a one-off issue, or symptomatic of a larger problem.

Each mobile security app's score ignores price and is based on:

  • 60% effectiveness - includes malware protection and anti-phishing
  • 20% theft recovery
  • 15% ease of use
  • 5% features

If a security app earns a total test score of 72% or above, we’ll award it our Best Buy recommendation.


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