Because of the tight security Apple puts into its iOS operating system, it's next to impossible to install spyware on an iPhone unless it's been jailbroken. Once an iPhone has been jailbroken, however, all bets are off. If someone gets his hands on your iPhone and jailbreaks it, installed spyware makes it difficult -- but certainly not impossible -- to detect that your device has been tampered with. If you leave your iPhone unattended or if you use iCloud, anyone who figures out your Apple ID and password could use spyware to access your data without actually installing software on your iPhone.
Jailbreaking and Spyware
A jailbroken iPhone poses a serious risk for spyware because it makes it easy to hide the apps. If you have jailbroken your phone -- or worse, let someone jailbreak it for you -- it may be impossible to determine if you are being spied on. According to forensics expert Michael Robinson in a 2012 Forbes interview, there may be no way for an average person to detect spyware. Software like Spyera hides itself and its log files, making it difficult even for security experts to trace. The only way to ensure that a jailbroken iPhone is spyware-free is to restore it to Apple's factory settings.
Determining if an iPhone Is Jailbroken
Unfortunately, determining if an iPhone has been jailbroken can be difficult when spyware is involved. Many spyware programs are not only designed to be hidden from view, but also hide other utilities, including Cydia, that you normally find on a jailbroken iPhone. To find out if this is the case on your iPhone, drag your finger downward from the center of the iPhone's home screen and type "cydia" in the Search field. If Cydia is found in the search, your iPhone has been jailbroken. If someone has taken the time to hide the Cydia app from your home screen, there's a good chance that spyware is on your iPhone.
Some iPhone spyware programs don't require an iPhone to be jailbroken, because they're not installed on the device. Instead, the spyware monitors your iCloud account and, whenever your iPhone syncs with iCloud, the spyware downloads your files from the Internet. Open "Settings" from the home screen and select "iCloud." If you never set up iCloud on your iPhone and find it's activated, there's a good chance that someone else did, perhaps with the intent of spying on you. You can delete the iCloud account by tapping the button at the bottom of the screen. If you do use iCloud, change your Apple ID password often.
If anyone knows your Apple ID password, they can access your iPhone's data simply by connecting it to a computer with a USB cable. Because this takes time, you don't have to worry much, provided you don't leave your iPhone unattended. Again, change your Apple ID password often. Long passwords using a combination of upper- and lower-case letters, symbols and numbers are the most difficult to hack. Never use easy-to-guess words or write your password down.
The Myth of Fingerprints
Many websites recommend that you watch for strange activity on your iPhone to determine if you're being spied on. These supposed spyware fingerprints include strange SMS text messages, shortened battery life and an active data icon on the home screen when you're not actively using the iPhone. While these symptoms may indicate that a poorly designed spyware program has been installed on your iPhone, they may also be due to other things -- like spam text messages, active background apps or automatic downloads. Additionally, the absence of these tell-tale symptoms by no means guarantees that your jailbroken iPhone isn't being monitored by spyware.