SDR: The Must Have Pentesting Tool

Imagine this: you’ve just parked in the parking garage after driving your way through the chaotic downtown streets of Chicago. It’s slightly overcast outside and the wind carries a bone chilling breeze. As you get out of your car, you press the power button located somewhere close in proximity to where the keyhole of your last vehicle was. When you press the button, your keyfob and car talk to each other. The engine goes silent and your vehicle is now off with a push of a button. You leave the car and lock it from the keyfob. From there, you walk into your office building for a normal day at work of processing paperwork, typing in an excel spreadsheet, and all of the usual business that takes place during the weekly nine to five hustle.

Now, it’s five in the evening. The sun is shortly going to disappear beyond the horizon. You leave the office thinking about the dinner you’re going to eat, any house chores that remain to be done, and the loathing feeling of waking up to tomorrow morning’s alarm clock. As you walk into the parking garage, you make your way up to the third level. Down the middle aisle you walk from one into the other, your mind full of everything that has to be done before you go to bed and start a new day. When you reach the end, you realize you might have walked past your car as you were deep in thought. You retrace your steps down the aisle and come to the spot your pretty sure you remember parking. However, it is empty. You check the whole third level. Your car is no where to be found.

In our world, everything is going wireless. We are in the age of the Internet of Things (IoT.) This has been happening for awhile and is catching on more and more in the public landscape. I haven’t exactly seen IoT refrigerators hit the sales floor of my local HomeDepot, but I know they are out there. What I see are “smart” home security systems that allow users to connect to their security system from a phone app. Wireless key fobs are locking, unlocking, and starting our vehicles. The lamp on the end table is controlled from a phone.

These new devices are entering our daily lives fast. All of this has the capability of enhancing our lives, but it comes at a cost, which we are all aware of. There are severe security risks involved in all of this. Anyone watching closely sees this happening. Databases are unsecured. Communications protocols aren’t great. Some of these technologies aren’t even encrypting their traffic. As we integrate these devices into our lives, we need to make sure they are secure and know their weaknesses.

There are many tools out there to test for possible security holes, but I wish to focus on one specifically. Probably one most haven’t considered. It’s the SDR (Software Defined Radio) Dongle.

What’s a SDR Dongle? Simply put, it is a wide-band receiver. The amazing thing about these dongles is how cheap they are and what they can do. The dongle itself is the wide band receiver that receives a large range of frequencies. Connected to a computer, phone, or tablet, the signals are processed. The best practice is using a technique referred to as Direct Digital Sampling. The hardware on your computer, along with the software, will interpret the signals. The great thing is, it can be used for any kind of signals. The analog AM broadcast station to receiving complex digital signals such as TV channels. This includes signals being sent by the smart devices.

Many of us in the tech world may have heard of ones like HackRF, which are great. However, there are much cheaper options. RTL-SDR dongles can be bought off of Amazon for about $25 as a whole kit including cables, antenna, and free software.

RTL2832U is the one I mentioned above that can be bought off amazon for as little as $25. This specific dongle can receive frequencies of 24MHz to 1.766GHz. Then by applying direct sampling, frequencies from 500KHz to 24MHz are open for listening.

How is this useful? Well, last years cars were being hacked and stolen in Chicago. These were all cars that used wireless key fobs to start their vehicles. The hackers had found out how bad the security between the communications of the keyfobs and cars was.

Having a sufficient SDR dongle, one can sit behind a computer and watch all of our IoT and wireless devices communicate. A good portion of the time, these communications are not very secure. SDRs put the power in all of our hands the power to analyze these packets of data and test for ourselves how secure our devices are.

Bottom line, an SDR is a must have tool for both the hacker looking to penetrate systems and for the security conscious person who performs their own home security audits to the professional security expert.


Categories: Security

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