As they proliferate, police body cameras have courted controversy because of the contentious nature of the footage they capture and questions about how accessible those recordings should be.

But when it comes to the devices themselves, the most crucial function they need to perform—beyond recording footage in the first place—is protecting the integrity of that footage so it can be trusted as a record of events. At the DefCon security conference in Las Vegas on Saturday, though, one researcher will present findings that many body cameras on the market today are vulnerable to remote digital attacks, including some that could result in the manipulation of footage.

Josh Mitchell, a consultant at the security firm Nuix, analyzed five body camera models from five different companies: Vievu, Patrol Eyes, Fire Cam, Digital Ally, and CeeSc. The companies all market their devices to law enforcement groups around the US. Mitchell's presentation does not include market leader Axon—although the company did acquire Vievu in May.

In all but the Digital Ally device, the vulnerabilities would allow an attacker to download footage off a camera, edit things out or potentially make more intricate modifications, and then re-upload it, leaving no indication of the change. Or an attacker could simply delete footage they don't want law enforcement to have.

'I can connect to the cameras, log in, view media, modify media, make changes to the file structures. Those are big issues.' Josh Mitchell, Nuix

Mitchell found that all of the devices he tested had security issues that could allow an attacker to track their location or manipulate the software they run. He also found problems with the ecosystem of mobile apps, desktop software, and cloud platforms that these cameras interact with. Additionally, Mitchell says that some of the more sophisticated models, which contain radios for Bluetooth or cellular data connectivity, also have vulnerabilities that can be exploited to remotely stream live footage off the cameras, or to modify, add, and delete the footage stored on the devices.

"With some of these vulnerabilities—it’s just appalling," Mitchell says. "I approached this research by trying to find industry trends that are prevalent across multiple devices. There are issues for each of the five devices I looked at that are specific to that device, but there are also trends in general across all of them. They are missing many modern mitigations and defenses."

Four of the five body cameras Mitchell tested have a Wi-Fi radio—the CeeSc WV-8 does not—and all of those broadcast identifying information about the device. Sensitive gadgets like smartphones have started randomizing these IDs, known as MAC addresses, to mask them. But the body cameras Mitchell looked at use predictable formats that give away too much information, like make and model plus a code for each device.

That means attacker could use a long range antenna to track cops. And as Mitchell points out, body cameras are often only activated when police carry out certain operations, or anticipate particular interactions. Noticing that 10 body cameras all activated at once, in a localized area, could foreshadow a raid, for instance. Mitchell fears that the exposure could pose a safety risk to law enforcement.

Mitchell says that all of the devices also have shortcomings in validating the code they run and the data they store. He found that none of the models he tested uses cryptographic signing to confirm the integrity of firmware updates, a common Internet of Things lapse. Without it, an attacker might develop malicious software that could be delivered to different devices in different ways based on their other vulnerabilities—through exposed desktop software or remote programming, for example. Once introduced, the devices will run any firmware without question.

More specifically problematic: The bodycams don't have a cryptographic mechanism to confirm the validity of the video files they record either. As a result, when the devices sync with a cloud server or station PC, there's no way to guarantee that the footage coming off the camera is intact. "I haven’t seen a single video file that’s digitally signed," Mitchell says.