That kind of technology is now available preloaded in today's most popular smartphones, including the iPhone 5s, Galaxy S4, HTC One and Nexus 5.
Software called mSpy is capable of recording your calls, monitoring your Internet use, tracking what you type, monitoring your SMS, WhatsApp and Skype conversations and pinpointing your location. The company claims that the person you're spying on will have no idea that you're seeing their information.
This software has been around since 2011, but now the company is selling phones that come with a one-year subscription to mSpy preinstalled. The surveillance program, which apparently runs in an "invisible mode" that doesn't interfere with a phone's normal operations, is available as a download as well for a range of Android, iOS and BlackBerry devices. You can see the full list here.
The creators behind the software, My Spy, have included an important caveat on their legal page, however. The company acknowledges that installing surveillance software on a device for which "you do not have proper authorization" is considered a federal or state violation of the law "in most cases." Failure to notify users that they're being monitored is also against the law in "most cases," My Spy warns in their legal notice.
"We absolutely do not endorse the use of our software for illegal purposes," the company says on its legal page.
The London-based company just set up shop in New York City's Financial District, according to BetaBeat. My Spy is touting the software for use cases including a parent checking in on their child or monitoring an employee's mobile activity in the workplace. The technology, according to Forbes' Adam Tanner, is incredibly accurate. Not only did mSpy track down the addresses of locations he had visited, but it listed the longitude and latitude coordinates, the time he had visited each location and a map view of each spot.
My Spy's decision to release smartphones with its software preinstalled just adds to mSpy's discretion. Previously, if you wanted to monitor someone's phone activity you would have to obtain that person's phone, hope it's compatible with the software, and install it yourself. Now, you can simply give someone a brand new iPhone or Galaxy S4 as a gift and there's a strong possibility the software will go unnoticed if you don't alert that person.
At the same time, other companies are creating smartphones specifically for improving privacy. The recently announced Blackphone, for example, runs on a more secure version of Android developed by Geeksphone and Silent Circle known as PrivatOS. The phone is capable of encrypting text messages so that only the sender and a receiver using the Blackphone or Silent Circle's software can see its contents.