Duo Labs: Deciphering the Messages of Apple’s T2 Coprocessor

In 2018, we released two whitepapers exploring Apple’s T2 coprocessor. The first paper explored the new system architecture of the late 2017 iMac Pro and 2018 MacBook Pro and how the inclusion of the T2 coprocessor enabled the secure boot and encrypted storage capabilities of this new platform. The second paper performed a deep-dive into the Secure Boot process and raised the concern that the T2 coprocessor, running a full version of BridgeOS, may expose a large attack surface. In this article, we explore the exposed services, identify the communications transport and decipher the protocols macOS uses to communicate with the T2 coprocessor. It will shock nobody that the T2 coprocessor communicates with macOS using Apple’s XPC interprocess communication mechanism. However, since the low-level workings of this communication mechanism are documented sparsely or not at all, this article aims to record not only the standard message format, but also how the T2’s use of XPC messaging appears to differ from conventional use of XPC. Building upon this understanding of the low-level communication channel, we demonstrate how one may analyze the network traffic between a macOS client and a T2 server and use this to exercise additional T2 functionality. […]




Duo Labs: organizations can be “software secure but firmware vulnerable”

Duo Labs, who has EFIgy, an EFI firmware update status tool for Mac, is interviewed by InfoSecurity Magazine on the topic of EFI security:

[…]Although efforts to compromise EFI are most often carried out as part of highly targeted attacks, they remain a major threat to organizations, he warned. […] Smith revealed newly updated research from Duo Security which details shortcomings in Apple’s EFI update processes. Drawing on data collected from 73,000 customer machines, the findings show that 4.2% were running the wrong EFI version – much higher than the 1% or so expected. That rose to nearly 43% for the oldest Mac model on the market, dating back to 2015. The results also showed that organizations could be “software secure but firmware vulnerable.” […] He called on tech firms to introduce “the same degree” of transparency into the firmware update process as they do with software updates. Duo Security chose to study Apple because the firm’s singular ecosystem made it easier to analyze, but Smith warned that failings in the Wintel space are arguably even more acute.[…]



Duo on Apple firmware security (and new EFIgy release)

Nice article on latest Apple changes to firmware security, T2 processor, Secure Boot, etc, are discussed here. Maybe one day Apple will create a similar whitepaper.



Duo Labs releases EFIgy 10.13


Duo Labs releases: IDAPython, Coretex M Firmware and Amnesia modules

Examining Personal Protection Devices: Hardware and Firmware Research Methodology in Action
Todd Manning, Duo Labs
[…]This paper describes a methodology for retrieving device firmware, and for loading firmware into IDA Pro, a common disassembler. This paper focuses on the disassembly of this firmware, and the discussion of a novel approach to defeating readback protection discovered in one ARM Cortex M implementation. During the course of this research, I developed code for IDA Pro to assist in loading and grooming Cortex M firmware images. The IDAPython code is comprised of two modules. The first module annotates Cortex M vector tables, which gives IDA Pro hints about where code exists in the firmware image. The Cortex M module can automatically annotate firmware with a vector table located at the start of a firmware image, or can be tailored by the end user to work with relocated tables. The second module, called Amnesia, uses byte-level heuristics to detect ARM instructions in the firmware. Amnesia also contains heuristics that operate at the ARM instruction level to determine function boundaries based on common ARM function prologues and epilogues.[…]

Cortex M Firmware (cortex_m_firmware.py): This Cortex M Firmware module grooms an IDA Pro database containing firmware from an ARM Cortex M microcontroller. This module will annotate the firmware vector table, which contains a number of function pointers. This vector table annotation will cause IDA Pro to perform auto analysis against the functions these pointers point to. The Cortex M Firmware module also calls into the Amnesia module to automate discovery of additional code in the firmware image using the Amnesia heuristics.

Amnesia (amnesia.py): Amnesia is an IDAPython module designed to use byte level heuristics to find ARM thumb instructions in undefined bytes in an IDA Pro database. Currently, the heuristics in this module find code in a few different ways. Some instructions identify and define new code by looking for comon byte sequences that correspond to particular ARM opcodes. Other functions in this module define new functions based on sequences of defined instructions.



X-Ray, Duo Labs Android vulnerability tool

Duo has a new article on Android security out. The article mentions an Android vulnerability detection tool that Duo Labs has:

Another tool that can help users detect for known Android vulnerabilities is X-Ray, a Duo Labs tool that anyone can download and run on their Android-based phone and/or tablet. Now in version 2.0, this app safely scans for vulnerabilities and allows you to assess your current mobile security risk.