How to Tell If Someone Is Spying on Your Phone
Detecting spyware on your phone is difficult because it will usually be hidden or operating in stealth mode.
However, if someone is spying on your phone, there are common signs you can look out for. You may notice a rapid increase in your phone’s data usage, suspicious files or applications, or strange text messages that you don’t remember sending.
Your device may also show signs of malfunctioning behavior. These might include a significant decrease in battery life, overheating, unexpected reboots, or your screen lighting up when the device is in standby mode.
Here are 10 of the most common signs that someone is spying on your phone:
1. Unfamiliar Applications
Although the most sophisticated spyware is hidden, people occasionally misuse apps like parental control apps in order to spy on others.
If someone is spying on your phone using one of these apps, then the spyware will be hiding in plain sight.
Search your phone for any unfamiliar applications that you don’t remember downloading. Common ones to look out for include Net Nanny, Kaspersky Safe Kids, Norton Family, and Qustodio.
Skip to our section below on How To Remove Spyware for more.
2. Your Device is ‘Rooted’ or ‘Jailbroken’
‘Rooting’ an Android device or ‘jailbreaking’ an iOS device allows users to bypass the official app stores and install unapproved apps.
If your device has been rooted or jailbroken and you didn’t do it, that’s a strong indication that something suspicious is going on.
To check whether an Android device has been rooted, download an app called Root Checker.
To check if an iOS device has been jailbroken, look for an app called ‘Cydia’. Cydia is the app used to install software onto jailbroken phones. If you find it on your device, then it’s almost certain your phone has been jailbroken.
EXPERT ADVICE: When you buy a second-hand phone, restore it to factory settings to make sure it isn’t jailbroken or rooted. Find out how to do this here: Android or iPhone.
3. The Battery Is Draining Fast
If spyware is working continuously, it can drain your battery faster than usual. All batteries degrade over time though, so look for a significant and sudden change, rather than a gradual deterioration.
If you do notice a sudden change, check if any recently installed or updated apps are responsible, before concluding you have a problem. We’re often surprised at how power-hungry some social media apps can be.
4. Your Phone Is Getting Very Hot
If your device is running hot, it may be a sign that someone is spying on you by running spyware in the background.
This is especially relevant if your phone is heating up even when you’re not using it, or when you’re barely using it.
NOTE: Similarly, if there is a sudden drop in your phone’s processing speed, it could be because of spying. As more of its resources are directed toward the spyware app, your phone may start to run noticeably slower.
5. Unusually High Data Usage
An unusual surge in the amount of data your phone is consuming can sometimes be a sign spyware is running in the background.
The spy app needs to use data to send information back to the perpetrator, so a spike in data usage may indicate foul play.
To check your mobile data on iPhone, go to Settings then Mobile Data. You can see your overall data use, or scroll down to see how much mobile data individual apps are consuming.
To check your mobile data usage on Android, go to Settings > Network & Internet > Data Usage. Under Mobile, you’ll see the total amount of cellular data being used by your phone. Tap Mobile Data Usage to see how your data use has changed over time. From here, you can identify any recent spikes.
NOTE: These measures only track the use of cellular data (i.e. the data you use when not connected to WiFi). If your phone is always connected to a WiFi network, this won’t be much help in identifying spyware.
That said, some Android phones offer the option to “Show Wi-Fi Data Usage” too. Use this to monitor how much data your phone is using while connected to WiFi.
Again, high data usage is not always the result of spyware. You’ll need to rule out legitimate apps first by checking the data consumption and behavior of individual apps.
For example, we were alarmed to see our data use spiking, until we discovered our new podcast app was downloading lots of previous episodes.
6. Strange Activity In Standby Mode
Your phone can still receive messages and calls when it’s on standby (or in sleep mode), but it shouldn’t be lighting up or making noises for any other reason. If it is, then it may be a symptom of spyware.
Similarly, your phone’s screen should be off and not just darkened when in standby mode.
7. Issues With Shutting Down the Phone
Spyware apps might sometimes interfere with a phone’s shutdown process so that the device fails to turn off properly or takes an unusually long time to do so.
In 2014, Edward Snowden revealed NSA technology that prevents phones from switching off fully, to then use them for eavesdropping purposes. This is the result of a very sophisticated and highly-targeted attack, but it demonstrates that this form of spying is possible.
NOTE: Frequent and seemingly random reboots can also be an indicator that there is spyware on your phone.
8. Odd SMS Messages
Text messages can be used by spyware and malware to send and receive data. If you see outgoing messages that you didn’t send, it’s likely an indication that something’s not right.
Look out for unusual incoming messages, too. Primitive spyware apps will sometimes use SMS messaging to communicate with their base. The message will typically be coded in some way if it is associated with a spyware app.
There’s also services like Cerberus which send hidden commands within SMS messages that can make your phone take a picture and email it to the perpetrator, wipe your SD card, take a screenshot, and many other invasive things.
9. Autocorrect Is Misbehaving
Keyloggers are a form of spyware that keep a record of all your keypresses. Someone spying on your phone could use a keylogger to capture your messages and login details.
One possible sign that someone may be using a keylogger to spy on your phone is a misbehaving autocorrect system. The keylogger interferes with how the autocorrect function works, so if you notice it acting strangely or working significantly slower than usual, it may indicate that someone is spying on your phone.
10. Screenshot Quality
If you notice the quality of screenshots is worse than expected, that could be the result of spyware, according to Malwarebytes.
CAUTION: These symptoms are not exclusive to spyware. They can also be caused by other forms of malware. Adware, for example, can slow down your phone and use up data.
Similarly, there are websites that secretly mine your ‘spare’ CPU resources which can consume more than 5% of your battery power in ten minutes.
In these cases, your device is being exploited but you’re not necessarily being spied on.