With just a phone number, hackers can hear and record voice conversations, track a person’s whereabouts, read text messages, spy on a person, and steal information — such as contacts data, giving hackers the phone numbers of others for additional malicious actions.

In the investigation conducted by the CBS News Network, which aired "Hacking Your Phone" on the 60 Minutes television program, hackers quickly and without detection intercepted and recorded a congressman’s phone conversation by just knowing his phone number.