Unusual Performance Issues
Malware often works in the background, consuming your phone's resources and causing noticeable slowdowns or unexpected behaviour.
- Check for unexpected app crashes or apps taking a long time to load. Pay attention to apps that usually run smoothly.
- See if your phone is running unusually hot, even when you're not using demanding applications or charging it.
- Monitor your phone's battery drain. Go to
Settings>Battery>Battery usage(on some Samsung devices, this might beSettings>Battery and device care>Battery) and look for unfamiliar apps consuming a lot of power. - Observe if your phone is slowing down significantly, freezing, or restarting on its own without you initiating it.
Good to know
Unexpected app behaviour or a constantly hot phone can be indicators of hidden processes.
Suspicious Data Usage
Malware frequently communicates with remote servers, which can lead to a noticeable increase in your mobile data consumption.
- Review your mobile data usage by going to
Settings>Network & internet>Mobile network(on Samsung, this could beSettings>Connections>Data usage). Look for significant spikes you can't explain. - Check the data usage breakdown by app. Within the mobile network settings, you can usually tap on 'App data usage' to see which applications are consuming the most data. Look for apps you don't recognise or those using data excessively for their function.
- If you're on Wi-Fi, you might not see these spikes on your mobile bill, but abnormal background activity could still be present. Observe your Wi-Fi router's activity lights for unusual prolonged flashes.
Important
High data usage by an unfamiliar app is a strong indicator of potential malware activity.
Unwanted Pop-ups and Ads
Aggressive advertising and persistent pop-up windows are common symptoms of adware, a type of malware designed to generate revenue through advertisements.
- Notice if you are seeing frequent, intrusive pop-up ads, especially when you're not using a web browser or particular app.
- Observe if your web browser is redirecting you to unfamiliar websites without your input.
- Check your device for new browser toolbars or home page changes that you didn't approve.
- Look for unrecognised apps on your home screen or in your app drawer that you don't recall downloading. Sometimes these apps are disguised as legitimate utilities.
Tip
Adware can be very disruptive. Keep an eye out for any ads appearing outside of normal app usage.
Unusual Phone Bill Charges and Permissions
Some malicious software can make unauthorised calls, send premium SMS messages, or access sensitive personal information, leading to unexpected charges or privacy breaches.
- Carefully review your phone bill for any unexpected charges, such as premium rate SMS messages or calls you didn't make.
- Check app permissions for suspicious apps. Go to
Settings>Apps>See all apps, then select an app and review its 'Permissions'. Look for apps requesting permissions that don't align with their function (e.g., a simple game wanting access to your contacts or SMS). - Look for new accounts or logins in apps that you haven't authorised, which might indicate credential theft.
- If friends or family report receiving strange messages or emails from you that you didn't send, your device may be compromised.
Important
Always scrutinise app permissions; they can reveal what an app is truly capable of doing on your phone.
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JD
Written by
Jordan DicksonFounder, CyberSecurityGuides
Founder of CyberSecurityGuides, writing practical, jargon-free guides that help everyday people recover from and protect against online attacks.
Reviewed by CSG Security Engineers