The BIOS Blog

Welcome to the dark corner of BIOS reverse engineering, code injection and various modification techniques only deemed by those immensely curious about BIOS

Thursday, August 18, 2016

Firmware/BIOS-related Patent Filings

I don't know if security researchers are used to looking at patent filings--because I'm not officially one of them. However, I found that reading and trying to understand firmware/BIOS-related patent filings is enlightening. It is also interesting because the filings are related to each other via cross-referencing, which make the activity all the more interesting, given enough time to dig into it. Among other thing, it provides a view ahead in this cat and mouse game of protecting and breaking firmware. These are some of my picks (not necessarily new ones):
The one that interest me the most is the last one because it's a sort of insight into Baseboard Management Controller (BMC) stuff. I hope you enjoy the patent filings as much as I do ;-)

Saturday, July 23, 2016

UEFI Boot from Web

I think I've been living under a rock in these last few months and not exactly following UEFI development. Nonetheless, I managed to spot this stuff over at What's interesting is the SDK supports "Firmware Boot from Web" so to speak. This is the relevant excerpt:
The Intel® Server Board S1200RP UEFI Development Kit supports Pre-Execution Environment (PXE) boot for IPV4 and IPV6 networking using on-board and add-in networking devices. Because of added initialization time, network boot for the four onboard networking devices is disabled by default in firmware setup. Users can enable PXE boot for on-board networking by enabling the ’EFI Network’ setting in the firmware setup menu.
EDKII Menu -> Advanced -> Network Configuration
As of SDV.RP.B6, the Intel® Server Board S1200RP UEFI Development Kit supports UEFI HTTP and HTTPS boot. These features are described in whitepapers located on the Tianocore github wiki:
Well, it could be double-edged sword from security standpoint. It depends on who you ask and what it's being used for.

Anyway, this is my take on this:

  • My "educated" guess is: This stuff emerge from Intel collaboration with the so-called Hyperscalers--Hyperscalers is what some people call them ( The Hyperscalers (Google, Facebook, Amazon, Azure, Alibaba, Baidu, Tencent) are running lots of web servers. Therefore, it makes sense for them to make it possible for their machines to boot just off of the webservers instead of preparing another "PXE Boot server" due to the prevalent web server in their bit barns. I think that Intel wants to trickle-down the same stuff into the masses, but as the first step, the Enterprise sector is what Intel targets.
  • Present day flash (is it still Flash??) memory used for firmware storage is spacious enough to cram a (compressed?) HTTP/HTTPS client into it. It would hardly possible to do that just several years ago due to the space constraint in the firmware chip on the motherboard. I didn't say this is impossible years ago because I have worked with extremely limited firmware space in non-PC platform that somehow managed to cram HTTP server into space less than 1MB, along with hardware configuration software stuff. 
  • This made it possible to boot from the cloud if anyone wants to implement such a stuff. But, it would entails a huge security "nightmare" if you ask me.

Thursday, May 26, 2016

BIOS Disassembly Ninjutsu PDF Moved to GitHub

The primary download site for BIOS Disassembly Ninjutsu PDF (free) is now moved to  (direct download at The previous download at 4shared is a malware-invested place, thus the change.

The addendum to the book is also included in the GitHub repository.

Monday, April 18, 2016

Moving Winflashrom code to Github

I ported Coreboot (formerly LinuxBIOS) flashrom utility to Windows a long time ago as my activity in Google Summer of Code and named it winflashrom. Because will be shutdown this year, I moved the code to github:

This is old news because the code haven't been updated for years. However, it might still relevant for those who want to port flashrom or other similar utility to present day Windows. I haven't developed Windows driver anymore since Windows Server 2003. I'm not even sure if WDM-style driver is still in use in Windows. But, I might be returning to develop Windows driver this year. So, yeah, you (and I) never know.