Without a high degree of tech-savviness, it isn't possible, as of 2015, to spy on someone through his cell phone and pick up any meaningful information, and doing so is illegal. However, researchers have created spyware programs that log keystrokes and use voice recognition to mine passwords and other data.
One app, developed by a team of researchers in 2012, supposedly allowed the phone to collect audio and occasionally snap photos without the user's consent, and to create a digital map of the surrounding room. However, PCWorld contends that it would be impractical to use such an app because of the amount of data to sift through. Also, a diligent person would keep the phone clean of any malware.