Category: HackRF

Using HackRFs to Locate a UAV Transmitter via Signal Strength Analysis

During the 2019 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting conference, authors Xuemei Huang, Kun Yan, Hsiao-Chun Wu and Yiyan Wu presented a research paper titled "Unmanned Aerial Vehicle Hub Detection Using Software-Defined Radio". In their work they describe how they were able to use three HackRFs to determine the location of a UAV drone transmitter. The method they use is fairly simple as it makes use of path loss propagation models to determine an estimated distance from each HackRF, so prior knowledge of the transmitter properties is still required.

The applications of unmanned aerial vehicles (UAVs) have increased dramatically in the past decade. Meanwhile, close-range UAV detection has been intriguing by many researchers for its great importance in privacy, security, and safety control. Positioning of the UAV controller (hub) is quite challenging but still difficult. In order to combat this emerging problem for public interest, we propose to utilize a software-defined radio (SDR) platform, namely HackRF One, to enable the UAV hub detection and localization. The SDR receiver can acquire the UAV source signals. The theoretical path-loss propagation model is adopted to predict the signal strength attenuation. Thus, the UAV hub location can be estimated using the modified multilateration approach by only three or more SDR receivers.

Unmanned Aerial Vehicle Hub Detection Using Software-Defined Radio

Using a HackRF for GPS Spoofing on Windows

Over on the TechMinds YouTube channel a new video titled "GPS Spoofing With The HackRF On Windows" has been uploaded. In the video TechMinds uses the GPS-SDR-SIM software with his HackRF to create a fake GPS signal in order to trick his Android phone into believing that it is in Kansas city.

In the past we've seen GPS Spoofing used in various experiments by security researchers. For example, it has been used to make a Tesla 3 running on autopilot run off the road and to cheat at Pokemon Go. GPS spoofing has also been used widely by Russia in order to protect VIPs and facilities from drones.

GPS Spoofing With The HackRF On Windows

RTL-SDR and HackRF Used in Mr. Robot – A TV Drama About Hacking

A few readers have written in to let us know the role SDRs played in the last season of "Mr. Robot". The show which is available on Amazon Prime is about "Mr. Robot", a young cyber-security engineer by day and a vigilante hacker by night. The show has actual cyber security experts on the team, so whilst still embellished for drama, the hacks performed in the show are fairly accurate, at least when compared to other TV shows.

Spoilers of the technical SDR hacks performed in the show are described below, but no story is revealed.

In the recently aired season 4 episode 9, a character uses a smartphone running an SSH connection to connect to a HackRF running on a Raspberry Pi. The HackRF is then used to jam a garage door keyfob operating at 315 MHz, thus preventing people from leaving a parking lot. 

Shortly after she can be seen using the HackRF again with Simple IMSI Catcher. Presumably they were running a fake cellphone basestation as they use the IMSI information to try and determine someones phone number which leads to being able to hack their text messages. The SDR used in the fake basestation appears to have been a bladeRF.

HackRF Used on Mr Robot
HackRF Used on Mr Robot

In season 4 episode 4 GQRX and Audacity can be seen on screen being used to monitor a wiretap via rtl_tcp and an E4000 RTL-SDR dongle.

E4000 RTL-SDR Being used for Wiretap Monitoring
E4000 RTL-SDR Being used for Wiretap Monitoring

Did we miss any other instances of SDRs being used in the show? Or have you seen SDRs in use on other TV shows? Let us know in the comments.

Using a HackRF to Investigate Why WiFi on the Raspberry Pi 4 Doesn’t work when Running HDMI at 1440p

The Raspberry Pi 4 launched with it's fair share of problems, but a new problem seems to have been recently discovered and documented. It turns out that the Pi 4's WiFi stops working when running at a screen resolution of specifically 1440p.

Suspecting interference generated by the HDMI clock, Mike Walters (@assortedhackery) used a HackRF and a near field probe antenna to investigate. By placing the near field probe on the Raspberry Pi 4's PCB and running a screen at 1440p resolution he discovered a large power spike showing up at 2.415 GHz. This interferes directly with 2.4 GHz WiFi Channel 1.

An article by ExtremeTech article notes:

There’s a giant spike that could easily interfere with Channel 1 of a Wi-Fi adapter. So why is this happening? Because a 2560×[email protected] has a pixel clock of 241.5MHz and has a TMDS (transition-minimized differential signaling) clock of 2.415GHz, according to Hector Martin (@Marcan42). And what frequency does the RBP4 use for Wi-Fi? 2.4GHz. Which means… outputting on HDMI over 1440p can cause interference in a Wi-Fi channel.

The ExtremeTech article also notes that this problem is not unique to the Raspberry Pi 4 only. It turns out that USB 3.0 hardware is to blame, and this problem has occurred before with USB3.0 hard driver and on some MacBooks.

While the interference appears to be localized to the near field around the Pi4 PCB, we suspect that you could use TempestSDR to remotely eavesdrop on the Pi 4's video output if the interfering signal was boosted.

Investigating Problems with the Tesla HomeLink RF Signal with a HackRF and GNU Radio

Tesla vehicles have a feature where they can copy and mimic a garage door remote via a built in transmitter on the car itself. This frees you from having to carry around a garage door key fob, and you can simply open your garage door by pressing a button on the car's LCD screen.

However, some people have reportedly been having a little trouble with this feature as in some cases the garage door would begin opening, and then suddenly stop opening as if the keyfob button had been pressed twice.

Over on YouTube CWNE88 decided to investigate this problem using his HackRF and GNU Radio. From a simple waterfall he was able to determine that the Tesla actually transmits the mimic'd garage door signal for a full two seconds.

As a keypress from the original keyfob would typically result in a much shorter transmission, CWNE88 believes that the long two second transmission could in some cases be seen as two transmissions by the garage door, resulting in an open, and then close command being detected. 

Tesla HomeLink RF Signal

Tutorial on Performing a Replay Attack with a HackRF and Universal Radio Hacker

Over on YouTube channel Tech Minds has uploaded a short tutorial video that shows how to perform a replay attack with a HackRF and the Universal Radio Hacker software. A replay attack is when you record a control signal from a keyfob or other transmitter, and replay that signal using your recording and a TX capable radio. This allows you to take control of a wireless device without the original keyfob/transmitter. This is easy to do with simple wireless devices like doorbells, but not so easy with any system with rolling codes or more advanced security like most car key fobs.

In the video Tech Minds uses the Universal Radio Hacker software to record a signal from a wireless doorbell, save the recording, replay it with the HackRF, and also analyze it.

Universal Radio Hacker - Replay Attack With HackRF

SDR in the Local Newspaper: Investigating an RF Dead Spot for Car Key Fobs

Reddit user [SDR_LumberJack] writes how he was recently featured in his local newspaper [Part2] in Ontario, Canada thanks to his efforts in helping to hunt down the cause of an RF deadspot with an SDR. He began his journey by reading a story in his local newspaper called the [Windsor Star]. The story was about locals having found a ‘dead-spot’ for car key-fobs. In the dead-spot key-less cars wouldn’t start, key-fobs wouldn’t unlock cars, and alarms would go off.

Being intrigued by the story [SDR_LumberJack] investigated by driving around with an RTL-SDR, HackRF and a laptop running SDR#. Eventually he found that there was what appeared to be a WBFM Broadcast radio station interfering at 315 MHz. This frequency happens to fall into the ISM radio band that used by car remotes and key-fobs. The exact source of the interference hasn’t been nailed down just yet though.

While it’s possible a broadcast station is at fault it is also possible that his SDR was just overloading, causing broadcast FM imaging. Perhaps a WBFM filter could be used to prevent signal imaging that could interfere with the investigation.

Hopefully [SDR_LumberJack] will continue his investigation and we’ll get an update on this story.

If you’re interested, back in 2016 we posted a very similar story about the exact same thing happening at a car park in Brisbane, Australia. The conclusion to that story was that the dead-spot only occurred in particular locations in the car park, and this was due to the shape of surrounding building causing the RF signals to reflect off the walls and distort the signal.

SDR_LumberJack in the local newspaper
SDR_LumberJack in the local newspaper

An Introduction to Pagers with the HackRF PortaPack and an RTL-SDR

Over on YouTube user HackedExistence has uploaded a video explaining how POCSAG pager signals work, and he also shows some experiments that he's been performing with his HackRF PortaPack and an old pager.

The Portapack is an add on for the HackRF SDR that allows the HackRF to be used without the need for a PC. If you're interested in the past we reviewed the PortaPack with the Havok Firmware, which enables many TX features such as POCSAG transmissions.

POCSAG is a common RF protocol used by pagers. Pagers have been under the scrutiny of information security experts for some time now as it is common for hospital pagers to spew out unencrypted patient data [1][2][3] into the air for anyone with a radio and computer to decode.

In the video HackedExistence first shows that he can easily transmit to his pager with the HackRF PortaPack and view the signals on the spectrum with an RTL-SDR. Later in the video he explains the different types of pager signals that you might encounter on the spectrum, and goes on to dissect and explain how the POCSAG protocol works.

Intro to Pagers - POCSAG with HackRF