Are Cell Phone Calls Secure?

By Amanda Holden

Cell phones have a few security issues that should be carefully evaluated.
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The cell phone, a common sight across the United States, can be found almost anywhere. With dozens of service providers and newer, more feature-rich models crowding onto the market each year, it's easy to forget that cell phones still have a few security issues when it comes to making calls and don't always provide the best security.


Although illegal, thieves and criminals may use surreptitious tactics to listen in on the calls you receive on your cell phone. Surprisingly easy, individuals can use radio frequency scanners and a digital data interpreter to eavesdrop on unsecured calls. The eavesdropper can hear an entire conversation, and if sensitive information is given, such as bank account or social security numbers and passwords, that information can be written down and used for criminal purposes later.


One method by which a thief can steal cell phone service without actually stealing a cell phone is known as "cloning." A thief intercepts the electronic serial number (ESN) and mobile identification number (MIN) of a cell phone during its normal operation. The thief programs this information into another cell phone, making it identical to the original. The thief can then make illegal or expensive long-distance calls, which are charged to the unsuspecting victim's phone bill.


Another insecure feature of cell phones can be exploited when a thief places a special call to the victim's phone and sets it to maintenance mode. This one-way connection prompts the victim's phone to act as a microphone, allowing an eavesdropper to listen to everything said within the earshot of the phone. The victim has no way of knowing this has occurred until she tries to place a phone call and must turn the phone off and back on to use it. As can occur with call monitoring, a thief can obtain sensitive information and exploit it using this one-way call maintenance feature.

Securing a Cell Phone

Users can take several precautionary measures to secure cell phones. The phone should be turned off when not in use to prevent it from being used as a microphone. Taking a cell phone into any area where someone might speak about classified or sensitive information should also be avoided.

Never leave your cell phone unattended, and whenever possible, avoid using it within several miles of an airport, mall or any other crowded location, as cell phone thieves often scan these areas for unprotected signals. Some cellular providers offer personal identification numbers (PIN) for phones, requiring that a user enter his pin number each time he makes a call. Although this may be time-consuming, it remains the best way to protect against cell phone cloning.