These warning signs could mean spyware is on your phone - and 9 ways to keep it secure

## Summary
Spyware is one of the biggest threats to your mobile security and can severely impact your phone's performance if you are unlucky enough to become infected. It is a type of malware that typically lands on your iPhone or Android phone through malicious mobile apps or through phishing links , emails, and messages. Also: Your Android phone's most powerful security feature is off by default and hidden - turn it on now This setting is found in most modern Android builds in Settings > Security > Allow unknown sources. (This varies depending on the device and vendor.) You can also check Apps > Menu > Special Access > Install unknown apps to see if anything is unfamiliar. An important point to mention is that sometimes spyware or other forms of malicious software might end up on your device via an initially benign app.

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These warning signs could mean spyware is on your phone - and 9 ways to keep it secure
Is your phone acting strange? It may be infected with spyware. Here are the warning signs and how you can stop it.
Written by
Charlie Osborne,
Contributing Writer
Contributing Writer
March 26, 2026 at 10:58 a.m. PT
Reviewed by
Elyse Betters Picaro
Moor Studio/Getty Images
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ZDNET's key takeaways
Spyware can track you, record calls, and steal phone data.
Watch for odd behavior, data spikes, unknown apps, and battery drain.
Use antivirus software, update regularly, and avoid untrusted app sources.
Spyware is one of the biggest threats to your
mobile security
and can severely impact your phone's performance if you are unlucky enough to become infected. It is a type of malware that typically lands on your
iPhone
or
Android phone
through
malicious mobile apps
or through
phishing links
, emails, and messages.
While appearing to be a legitimate software package or useful utility, spyware will operate quietly in the background to monitor your movements, spy on your activities, and may also record your conversations, whether they are phone calls or social media threads. You may find your actions screenshotted, your call records logged, and even your physical location tracked via GPS.
Also:
7 ways to lock down your phone's security - before it's too late
This information is then sent to a remote server and into the hands of someone else without your permission.
Similarly, a remote monitoring app promoted for parental use or work purposes could be abused and become a privacy invader rather than a legitimate service.
Let's explore the different types of spyware you might encounter, the warning signs of infection, and how to quickly remove it from your smartphone.
Spyware explained
It's helpful to know the basic differences among types of spyware before you tackle infections on your handset.
Nuisanceware is bundled with mobile apps. It interrupts your web browsing with pop-ups, changes your homepage or search engine settings, may try to force you to watch videos, and may collect your browsing data to sell to ad agencies and networks. Although considered
malvertising
, it is generally not dangerous, as it focuses on generating illicit revenue by forcing ad views or clicks.
Also:
As ransomware recedes, a new more dangerous digital parasite rises
There's also generic mobile spyware. It steals operating system data, clipboard data, and anything of value, such as cryptocurrency wallet data or account credentials. Spyware isn't always targeted and may be used in spray-and-pray
phishing
attacks.
Spyware may land on your device through phishing, malicious email attachments, social media links, fraudulent SMS messages, or physical device tampering.
Advanced spyware, sometimes also classified as stalkerware, is a step up from basic spyware. This malware is unethical and dangerous. It is sometimes found on desktop systems but is now more commonly installed on handsets. Stalkerware is typically used to spy on an individual and monitor what they do, say, and where they go, and is often linked to cases of
domestic abuse
.
Spyware and stalkerware may be used to:
Monitor emails, SMS, MMS messages, and other forms of communication sent and received, including Facebook and WhatsApp.
Intercept live cellular calls or Voice over IP (VoIP) applications.
Hijack camera functions to take photos and videos.
Screenshot mobile device screens and send them to a controller.
Track victims via GPS.
Conduct keylogging, account compromise, and data theft.
Finally, there's government-grade commercial spyware, with
Pegasus
among the best-known variants. Unless you're part of a group of specific interest to ethically challenged governments, it's unlikely that it will impact you due to the expense of targeting victims.
Spyware warning signs
There aren't always indicators of an infection attempt in real time, but the following scenarios could be warning signs that you are being targeted:
Receiving odd or
unusual SMS messages
, social media messages, or emails.
Strange permission, download, or software installation requests appear on your handset.
If your phone goes missing or is out of your possession for a period of time and then reappears with settings or changes you do not recognize, this may indicate that your device has been tampered with.
When it comes to stalkerware, initial infection messages may be more personal and tailored to the victim. Physical access to a handset may be necessary.
Also:
I clicked on four sneaky online scams on purpose - to show you how they work
There are also signs you can watch for that may indicate your phone has been compromised. The most common are:
Power: You may experience unexpected handset battery drain, overheating, or sluggish performance.
Behavior: Strange behavior, such as GPS or camera functions turning themselves on and off without your in

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## Expert Analysis

### Merits
- This is the easiest solution available, but it may not be effective in every case.
- If you suspect account compromise, change the passwords for every important account you have.
- An important point to mention is that sometimes spyware or other forms of malicious software might end up on your device via an initially benign app.
- They contain security fixes and patches and are one of the most important lines of defense against malware.

### Areas for Consideration
- How to remove spyware from your smartphone Spyware is often hard to detect and can be difficult to remove.
- Do not tamper with your device if doing so would risk your physical safety.
- However, we have provided some tips below to mitigate the risk of future infections: Protect your device physically: Your first line of defense is to maintain adequate physical controls.

### Implications
- Tech Home Tech Security Cyber Threats These warning signs could mean spyware is on your phone - and 9 ways to keep it secure Is your phone acting strange?
- It may be infected with spyware.
- Spyware is one of the biggest threats to your mobile security and can severely impact your phone's performance if you are unlucky enough to become infected.
- While appearing to be a legitimate software package or useful utility, spyware will operate quietly in the background to monitor your movements, spy on your activities, and may also record your conversations, whether they are phone calls or social media threads.

### Expert Commentary
This article covers spyware, apps, device topics. Notable strengths include discussion of spyware. Areas of concern are also raised. Readability: Flesch-Kincaid grade 0.0. Word count: 2404.