Whether you missclicked or downloaded the wrong file, malware can infect your Android device or iPhone and you might not have even noticed. There are some signs that are completely obvious, but others are a little more discreet and take some snooping around to suss out.
Here are some warning signs that you might have an unwanted guest on your smartphone.
Pop-up ads
Advertisements spamming your phone, especially outside of an app, is a dead giveaway. Don’t ignore the problem, even if you’re a fan of Neon Genesis Evangelion who really appreciates seeing “CONGRATULATIONS” spread across their screen.
New apps
If your phone is packing a ridiculous number of applications like mine, then you might not notice when a new app creeps into your system. For both the sake of spotting malware and cleaning up your library of unused apps, it's worth taking the time to audit your current apps.
Shorter battery life
Malware does a lot in the background to wreak havoc on your device, and that takes power. So one of the telltale signs of malware infecting your device is if you experience shorter battery life. Battery life can vary, especially as a phone ages, so I recommend looking up the average battery life for your device to see if there's an obvious discrepancy.
Performance issues
Got a brand new phone and all of a sudden everything slows down to a crawl? Are apps randomly crashing on you? This is another sign that malware may have crept onto your device. This may be more difficult to spot on phones already experiencing slower performance, so keep an eye out for other signs if that’s the case.
Overheating
Unless you still have a Samsung Galaxy Note 7 hanging around, which you shouldn't, your device should not be scorching your hand. If your smartphone is spamming you with overheating warnings or is straight up crashing, especially in temperate environments, there might be a virus giving your phone a fever (my dad joke for the day).
Abnormal data usage
Unless you have a limited data plan and are remaining vigilant about your usage, it’s unlikely you’ll notice malware taking up all your data. Unlimited data users who have never checked their data metrics need to be more alert. It doesn’t hurt to check your data usage every once in a while, if not to see what apps you’re maybe spending a little too much time on.
Your contacts get spam
The most embarrassing and frustrating sign of malware is all your friends and family getting hit with spam messages that can potentially affect their devices. You’ll likely hear about this sooner than later, but as someone who doesn’t actually use SMS to contact people, it doesn’t hurt to check your default messaging app. Hopefully your contacts know what you sound like versus a spam bot imitating you, but the sooner you alert people the better.
What you can do
If you’re still not 100% certain whether or not your device is carrying around malware, there’s a few things you can do.
For iPhone users, navigate to Settings > General > VPN & Device Management to check if any unknown profiles are installed. If you don’t find anything here, go to Settings > Privacy & Security and check on your app permissions. This might be a bit tedious, but you should do a step by step inventory of app permissions and revoke access to apps that you aren't using, and delete ones that you don’t recognize.
For Android users, go to Google Play > tap your profile picture > Play Protect. This will scan your device for any harmful apps. It typically runs automatically, but it doesn’t hurt to do a manual check.
If you don’t find anything going down these routes, Android users can download one of the best Android antivirus software solutions, which can not only help locate malware but also delete it. Unfortunately, iPhone users don’t have access to traditional antivirus software because of how Apple sandboxes each app, but you can download security apps that can detect data breaches.
If you can’t manage to track down the issue, then resetting your device to factory settings may be the next step. In this case, you should set up your smartphone as a new device, as any backups can bring with it the malware that infected the system to begin with. Then reintroduce apps and services one by one to see if the issue continues, and if it happens again, you’ll know where the call inside the house is coming from and you can get rid of it — it could be something as simple as a browser extension.
I highly recommend changing passwords on critical services, like banking apps, using a different device. Monitor your smartphone for a while to see if the issue has been addressed before relogging into any sensitive apps.