fwexpl – PC Firmware Exploitation Tool and Library

Dmytro Oleksiuk (aka Cr4sh) has a VERY INTERESTING new firmware tool for Windows

PC firmware exploitation tool and library

Project includes the following components:
 * libfwexpl — Hardware abstraction library for Windows (see include/libfwexpl.h).
 * libdsebypass — Windows x64 DSE bypass exploit based on Secret Net 7.4 0day privileges escalation vulnerability (see include/libdsebypass.h).
 * driver — Kernel mode part of libfwexpl.
 * application — Application that implements System Management Mode code execution exploit for 1day vulnerability in SystemSmmAhciAspiLegacyRt UEFI SMM driver of Lenovo firmware.

  –target <N> — Select known target where <N> is a target number. If –target and –target-addr options are not specified — exploit will use heuristics to find EFI_BOOT_SERVICES structure address that neccessary for SystemSmmAhciAspiLegacyRt driver vulnerability exploitation.
  –target-list — Print all known targets information.
  –target-addr – Use manual address of EFI_BOOT_SERVICES.LocateProtocol field for SystemSmmAhciAspiLegacyRt exploit. This option will be ignored if –target was specified.
  –target-smi – Use manual SMI handler number for SystemSmmAhciAspiLegacyRt exploit. This option will be ignored if –target was specified. If –target-addr was specified without –target-smi — SystemSmmAhciAspiLegacyRt exploit will check all of the possible SMI handlers from 0 to 255.
  –smram-dump — Determinate current SMRAM address and dump it’s contents to file specified by –file option.
  –phys-mem-dump — Full raw physical memory dump into the file specified by –file option.
  –phys-mem-read <addr> — Read physical memory starting from specified address.
  –phys-mem-write <addr> — Write physical memory starting from specified address.
  –length <bytes> — Number of bytes to read or write for –phys-mem-read and –phys-mem-write.  
  –file <path> — Memory dump path to read or write, in case of –phys-mem-read this parameter is optional and when it’s not specified — application will print a hex dump of physical memory to stdout. In case of –smram-dump this parameter is mandatory.
  –exec <addr> — Execute SMM code at specified physical memory address.
  –dse-bypass — Install and exploit Secret Net 7.4 driver to bypass Windows x64 DSE.  
  –test — Run some basic libfwexpl tests.

To learn more about this project please read his blog post, “Exploiting SMM callout vulnerabilities in Lenovo firmware”:


Cr4sh on SMM exploits in Lenovo firmware!

Dmytro Oleksiuk aka Cr4sh has a new blog post on SMM exploits on Lenovo firmware! Very well written and detailed, with source code!

Exploiting SMM callout vulnerabilities in Lenovo firmware
Hi, everyone. In this article I’ll continue to publish my research in PC firmware security field. In previous article, “Breaking UEFI security with software DMA attacks”, I’ve shown how to exploit UEFI boot script table vulnerability and get access to the SMRAM using software DMA attack under Linux. This time we will talk about discovering and exploitation of SMI dispatch vulnerabilities in UEFI System Management Mode drivers. For anyone who’s not familiar with architecture of SMM phase firmware code on UEFI based platforms I’ll strongly recommend to read my other article “Building reliable SMM backdoor for UEFI based platforms”, especially the part about communicating with SMM code using software SMI.

SMM vulnerabilities that I will talk about in this article aren’t new. Around one year ago LegbaCore and Intel Security published two works: “How Many Million BIOSes Would you Like to Infect?” and “A New Class of Vulnerabilities in SMI Handlers” correspondingly, they rediscovered some security issues in SMI handlers code that was actually a known problem among PC firmware developers (for example, same attacks was described in Loïc Duflot work “System Management Mode Design and Security Issues” presented six years ago). Nevertheless, researchers were able to find and report a lot of firmware vulnerabilities of this class in products like Lenovo, Dell, HP laptops and many others (CERT VU#631788). To play with these vulnerabilities I got ThinkPad T450s laptop. According to original security advisory by Lenovo (apparently, it has a lack of technical details) — some unspecified SMM callout vulnerabilities were patched in the latest version of it’s firmware and everything that we need to do is just find out and exploit one of these vulns. […]




Dmytro Oleksiuk has a project called OpenREIL, an open source library and tools for Reverse Engineering Intermediate Language (REIL).

REIL was initially developed by Zynamics as part of their BinNavi framework, proprietary code analysis software written in Java. […] However, after Zynamics was acquired by Google they abandoned BinNavi, so, I decided to develop my own implementation of REIL. I made it relatively small and portable in comparison with original, the translator itself is just a single library written in C++, it can be statically linked with any program for static or dynamic code analysis. The higher level API of OpenREIL is written in Python, so, it can be easily utilized in plugins and scripts for your favourite reverse engineering tool (almost all modern debuggers and disassemblers has Python bindings). OpenREIL is not a 100% compatible with Zynamics REIL, it has the same ideology and basics, but there’s some changes in IR instruction set and representation of the traget hardware platform features. […]


Using UEFI_boot_script_expl on Lenovos

Dmytro “Cr4sh” Oleksiuk has a conversation on Twitter about using using his CHIPSEC-based exploit module against Lenovo models, noting some firmware vulnerabilities in Lenovo x220/x230 laptops.

Here are 5 tweets, let’s see how the non-deterministic WordPress.com rendering software will show them:

It is nice to hear “The most recent ones looks not vulnerable.” Maybe the Lenovo QA team is improving? 🙂 Looking forward to more research on this, more than just a few Tweets, his research is usually very verbose! Also, he has updated the readme on his update script today:


UEFI DMA attack research and code

Dmytro Oleksiuk (@d_olex) just wrote up some very interesting UEFI security blog post, with CHIPSEC-based sample code!

 Breaking UEFI security with software DMA attacks
Hi everyone! In this article I’d like to tell you more about UEFI vulnerabilities exploitation. Last time, in “Exploiting UEFI boot script table vulnerability” blog post I shown how to execute arbitrary shellcode during early PEI phase which allows to bypass security mechanisms that protects System Management Mode memory (SMRAM) from DMA attacks. Now we will perform such DMA attack on SMRAM to disable BIOS_CNTL flash write protection — it will give us the ability to write infected firmware to ROM chip on the motherboard. This attack can be used for installation of my SMM backdoor without having physical access to the target machine (in previous blog post I explained how it works and how to install it using hardware programmer). My software DMA attack approach for Linux operating system hijacks physical address of DMA buffer used by disk driver, concept of such attack originally was presented in BH US 2008 talk by Rafal Wojtczuk “Subverting the Xen hypervisor”.



UEFI SMM vulnerability research: SmmBackdoor

Dmytro ‘Cr4sh’ Oleksiuk has been looking into Intel Systems Management Mode (SMM) on UEFI systems. Yesterday he posted a blog with some information on this research, along with some source code. Check out the blog post, it’s a very long document with lots of figures, very good reading.

More Information: