Uploaded December 2019 | Updated September 2026, 2 days ago
For software to communicate with hardware, it needs to talk to a kernel-mode driver that serves as a middle-man between the two, helping to make sure everything operates as it should. In Windows that is done using the Kernel-Mode Driver Framework (KMDF).
These drivers are used to control everything in your computer, from small things like CPU fan speed, color of your motherboard LED lights, up to flashing a new BIOS.
However, as the code in these drivers runs with the same privileges as the rest of the kernel, malicious drivers can be used to compromise the security of the platform. To that end, Microsoft relies on WHQL, code signing, and EV Signing to prevent drivers which have not been approved by Microsoft from being loaded into the kernel.
Unfortunately, security vulnerabilities in signed drivers can be used to as a proxy to read and write hardware resources such as kernel memory, internal CPU configuration registers, PCI devices, and more. These helpful driver capabilities can even be misused to bypass and disable Windows protection mechanisms.
Let us teach you how these drivers work, show you the unbelievable risk they pose, and enjoy our walk of shame as we parade all the silly and irresponsible things we discovered in our research.
For software to communicate with hardware, it needs to talk to a kernel-mode driver that serves as a middle-man between the two, helping to make sure everything operates as it should. In Windows that is done using the Kernel-Mode Driver Framework (KMDF).
These drivers are used to control everything in your computer, from small things like CPU fan speed, color of your motherboard LED lights, up to flashing a new BIOS.
However, as the code in these drivers runs with the same privileges as the rest of the kernel, malicious drivers can be used to compromise the security of the platform. To that end, Microsoft relies on WHQL, code signing, and EV Signing to prevent drivers which have not been approved by Microsoft from being loaded into the kernel.
Unfortunately, security vulnerabilities in signed drivers can be used to as a proxy to read and write hardware resources such as kernel memory, internal CPU configuration registers, PCI devices, and more. These helpful driver capabilities can even be misused to bypass and disable Windows protection mechanisms.
Let us teach you how these drivers work, show you the unbelievable risk they pose, and enjoy our walk of shame as we parade all the silly and irresponsible things we discovered in our research.



![DEF CON 27 - Intro to Embedded Hacking-How you can find a decade old bug in widely deployed devices
From small business to large enterprise, VOIP phones can be found on nearly every desk. But how secure are they? What if your phone was spying on every conversation you have?
This talk is an introduction to hardware hacking and as a case study Ill use the [REDACTED] Deskphone, a device frequently deployed in corporate environments. Ill use it to introduce the tools and methodology needed to answer these questions.
During this talk, attendees will get a close up look at the operations of a hardware hacker, including ARM disassembly, firmware extraction using binwalk, micro-soldering to patch an EEPROM and get a root shell over UART, and ultimately uncover an already known decade-old bug that somehow remained unnoticed in the devices firmware.
Beyond the case study I will also address alternative tactics; some did not work, others may have but were not the lowest-hanging fruit. When it comes to hardware hacking, the process is as important as the result; knowing that there are multiple ways to reach the end goal helps researchers remain confident when hurdles arise. After the talk, attendees will have an increased distrust towards always-on devices; however, they will have the background knowledge to investigate the products and systems they encounter daily.
Intro to Embedded Hacking-How you too can find a decade old bug in widely deployed devices. [REDACTED] Deskphones, a case study. DEF CON 27 - Intro to Embedded Hacking-How you can find a decade old bug in widely deployed devices](https://i.ytimg.com/vi/OW95vw2_BxQ/mqdefault.jpg)






