While it’s probably not the best idea to run a self-diagnosis on yourself with WebMD, there’s absolutely no reason why you shouldn’t be diagnosing issues with your technology—especially your smartphone.

Is it time to declutter your smartphone? Or is it time to invest in a mobile antivirus to fend off malware?

Let’s take a look at the telltale signs of infected smartphones and how to keep yourself protected.

Symptoms of a virus-infected smartphone

Slower phone or faster battery drain

Slower devices can commonly be a sign that you’re either running out of storage space or using an outdated operating system. However, a more dire possibility is the presence of malware. A virus can find its way onto your phone either through a suspicious link that you’ve clicked on or hidden inside an app you’ve downloaded.

Sudden increase in data consumption

If you’ve found that your data usage has taken a sharp increase on your latest phone bill, chances are there’s a malicious code or program sending data from your phone to unknown servers. Or worse, your phone is being used to send texts or make calls to premium phone services—which leads to…

Messages being sent to your contacts

Some mobile viruses will send messages to contacts on your phone with links to infected software. Should any of your contacts click on these links and download any apps, their phones will also be infected.

Strange apps

If you see strange apps on your phone that you don’t remember installing, there’s a pretty high chance they’re viruses.

Persistent and aggressive ads

The sudden onset of pervasive ads is a big indicator that you’ve installed an app of unknown or nefarious origin that is pushing unwanted advertisements to your device.

Hijacked search engines

Are search results on your phone suddenly being rerouted to search engines or websites you’ve never heard of before? Are you finding it difficult to switch back to your default search engine or browser? You’ve definitely got a virus.

Keeping your smartphone protected

Keep your software up to date

Don’t ignore “update your device” prompts on your phone. Keeping your device software updated is one of the easiest ways to ensure you have a head start in thwarting the latest malware infections and fixing software bugs. Don’t want to be continually pestered with prompts? Set your device to perform updates automatically.  

Only install apps from trusted sources

This one is a no-brainer, by only installing apps from trusted sources, you can ensure that they’ve been authenticated. In other words, you’ll know exactly what’s going onto your phone.

Don’t open strange attachments

Never trust attachments of unknown origin. In fact, don’t trust all attachments sent to you by trusted sources—at least until you’ve verified its authenticity as phishing scams are extremely common.

Invest in a decent antivirus

While use of an antivirus won’t be a one-stop shop for mobile protection—in fact, our writer Lexie has written that it’s better to update your system than to use antivirus software)—it is worth considering as one aspect of your digital security. Especially when paired with a VPN!