*OS - Security & Insecurity Workshop -- Duration: 3 days
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Synopsis

This course, modeled after Jonathan Levin's "*OS Internals: Volume III", takes a practical approach to explaining the security of Apple's operating systems, by explaining the various mechanisms employed by Apple to secure the system - and yet demonstrating how they fail, time and time again. Through case studies of jailbreaks and Pegasus (the only weapons-grade malware caught in the wild), the techniques for protecting the OS integrity - as well as measures used to bypass them - are detailed. Code samples detailing usage of each mechanism are provided as actual examples for discussion in class. Actual jailbreak code, including the latest iOS 12.1.2 Liber* family of jailbreaks, is presented. Advanced tools - such as Xn00p, our live kernel inspection/debugging tool - allow unprecedented visualization of what happens behind the scenes in every step of the jailbreak process. This course is updated to the latest Darwin 19 beta releases!

Target Audience

Reverse Engineers, Security and/or Malware Researchers - both Mac and iOS - interested in getting to know Apple's Operating Systems and their security measures intimately.

Prerequisites

This course is an advanced course, and requires a priori familiarity with MacOS or iOS, as per Jonathan's Levin or Amit Singh's "Mac OS [and iOS] Internals" books. It does not discuss basic internals, but rather builds on them so as to focus on security. Participants are highly encouraged to read the books (see below, "Required Reading") throughly.

We would also suggest participants consider the basic MacOS/iOS Internals course prior to this one. For that course's alumni, this makes a perfect sequel and a chance to revisit internals - especially kernel aspects - in far greater detail.

• Knowledge of Mac OS X and/or iOS, and user mode programming.
• Knowledge of *OS kernel concepts: XNU = { Mach + BSD + IOKit }
• Knowledge of Mach IPC - ports and message format
• Familiarity with x86_64 and/or ARM32/64 is highly recommended
• Bring your own Mac/jailbroken i-Device (ask us about renting one for class!)
• Students must bring MacBooks with XCode 10.x + latest XNU Sources (4903+) installed (ask us about renting one!)
• For iOS examples, it is recommended that students be in possession of a provisioning profile, or use jtool/ldid to self-sign

Objectives

• Understand the MAC Framework in MacOS and the iOS Variants
• Understand kernel memory protections
• Explain the methodology employed by jailbreaks and malware alike to elevate privileges and obtain unrestricted access
• Understand how jailbreaks repeatedly find flaws and circumventions in Apple's mechanisms
• Understand the Apple Sandbox, and its profile language
• Explain common jailbreaking techniques, before and after kernel patch protection
• Understand attack surfaces in OS X and iOS (and its derivatives), particularly those of the kernel, kexts (I/O Kit) and system daemons.

Exercises

This course contains quite a few hands-on exercises, and walks through code samples (often in the form of guided instructor demos), as shown below.

Suggested Reading

The following books are suggested as additional references for this course:

• Mac OS X and iOS Internals (MOXiI) - Jonathan Levin - Wiley, 2012 (FREE!)
• Amit Singh - "Mac OS X Internals" (Addison-Wesley, 2006)
• *OS Internals:: Volume III - Security & Insecurity (2016, 2018 - v1.6)
• *OS Internals:: Volume I - User Mode (2017,2019 - v1.3)

MODULES

1. Introduction 1 hours An overview of the architecture of *OS variants, from a threat assessment perspective. Focus on different abuse cases, and the mitigation techniques devised by Apple to address and prevent them. Quick recap of the *OS Architecture High level presentation of mitigation techniques Attack surface of MacOS and the iOS variants Divergences between MacOS and iOS variants *. Monitoring 1-2 hours Explaining the reactive mechanisms by means of which system activity can be monitored (though not intercepted) and logged. This includes a detailed discussion of: Auditing (MacOS) KDebug DTrace (MacOS) FSEvents Stackshot Proc info 2. The Boot Sequence 2 hours The boot sequence - aside from starting up the system - is responsible for establishing and securing the chain of trust, which ensures component integrity. MacOS boot is (still) fairly lax, but that of the *OS variants is rigorously designed to be as bulletproof as possible. This module takes a close look at the stages of boot, focusing in particular on iBoot. Focusing on a purely reverse engineering approach, this module takes apart iBoot - from BootROM to kernelcache loading: Boot sequence components: BootROM, iLLB, iBoot and friends SHSH blobs and APTickets Attack surface and potential vulnerability discussion Reversing iBoot (once decrypted) Reversing the Secure Enclave Processor (SEP) image (once decrypted) 3. The Mandatory Access Control Framework 0.5-1 hours The Mandatory Access Control Framework (MACF) is the de-facto standard for all of Apple's security mitigation techniques - from code signing, through sandboxing. A legacy of TrustedBSD, although it is a "private" KPI, it is remarkably simple and, at the same time, powerful. Precursor: KAuth Introducing: MACF The MACF KPIs MAC Policies Creating a simple MACF policy Case study: MacOS Quarantine Case Study: MacOS 10.15 EndpointSecurity 4. AppleMobileFileIntegrity 2 hours Sworn nemesis of jailbreakers, AppleMobileFileIntegrity (amfi) has become the linchpin of Darwin security, controlling the kernel-enforcement of code signing and kernel-level entitlements. AMFI components (kext, daemon) Detailed breakdown of AMFI.kext Full reversing of amfid AMFI.kext as an entitlement enforcement The AMFI User Client iOS 12: CoreTrust 5. Sandboxing 2 hours The Apple Sandbox mechanism has evolved dramatically since its inception in MacOS 10.5 as "SeatBelt". It has also diverged in its implementations outside MacOS. Sandboxing Terminology Implementation in MacOS: The App Sandbox The Sandbox Profile Language (SBPL) Compiling profiles Decompiling profiles Creating custom profiles Debugging the sandbox User mode APIs Implementation in *OS: forcing Containers Sandbox extensions Detailed reversing of the Sandbox kernel extension System Integrity Protection as a manifestation of the Sandbox iOS 10 and the platform profile Darwin 18 and TCC integration 6. kobjects 3 hours Ports are mere 32-bit identifiers in user space, but kernel space reveals a vast menagerie of complicated objects, of which IPC ports are but one type. This module examines thoese objects in detail, including: The BSD objects (processes, threads and files) The ipc_object_t The ipc_port_t The task_t and thread_t Vouchers 7. Get in the (kernel) zone 3 hours Everything that user mode "sees" and touches is a figment of the kernel's memory. Understanding memory structures and management is paramount - for researchers and exploiters alike. This module discusses in depth the various allocation mechanisms of kernel memory The vm_map abstraction The pmap abstraction The Zone allocator Darwin 18: The Zone Cache Garbage collection, Feng Shui, and other techniques Zone ("kernel heap") hardening 8. Let's Get Physical 3 hours Apple is one of the only vendors to adopt proprietary protections for physical memory. Starting with the simple "WatchTower" KPP, Apple moved to introduce KTRR in the A10, followed by APRR (A11), along with novel applications such as PPL. But what do all these acronyms mean? And what is their impact on exploitation? A6-A9, iOS9+: KPP A10+: KTRR A11+: APRR A12+: PPL 9. Aie, Aie, IOKit 2 hours IOKit is the most advanced and powerful feature of XNU, allowing C++ code in kernel with all its might - Object orientation and inheritance - and all its weaknesses. IOKit objects have become crucial for many an exploit, both as a vector for vulnerabilities, and as a mechanism for kernel code execution. IOKit objects: Services and user clients Enumerating and identifying IOKit objects in *OS kernels Object corruption and fake objects Kernel code execution primitives (and how to survive without them) 10. Vulnerabilities and Exploits 6.5 hours (and interleaved throughout other modules) We turn our attention to discuss a few examples from the MacOS world, as well as past jailbreaks - as many as time permits, with actual code samples showing point proofs of concept on vulnerable (past) versions of MacOS and *OS. Exact samples may change by time of training, but at this point are: The 9.3.5 ("Phoenix") jailbreak Ian Beer's 11.1.2 async_wake User mode jailbreaks: Brandon Azad's Blanket The most recent iOS 12.1.1 Mach voucher bug (Brandon Azad's and S0rryMyBad's methods) Discussion of the OSUnserialize* bugs behind Pegasus The QiLin post-exploitation toolkit Operation Triangulation (< 16.6) @felixpb's amazing physical memory exploits Dopamine Jailbreak

Frequently Asked Questions

• How is this course different from the standard OS X/iOS Internals course you offer?
  Radically. This is a sequel to the standards internal courses, and does not actually discuss various aspects - like the MachO format, runtime environment, Mach objects, and IOKit - which are deemed to be prerequisites for this course.


• Do I aboslutely have to know [Intel/ARM32/ARM64/Any] Assembly?
  If you know any flavor of Assembly, learning others is fairly easy. We provide a crash refresher (though you'll likely need to do that as homework). If you don't, you might be challenged when reviewing the examples - some of which require reverse engineering because they are close source - do require assembly. We'll try to explain them in plain English as well.


• Why such strict prerequisites?
  Because. It is already extremely tight to fit all this information - this alone could have taken double that time. But we already have five days in the standard course, so we opted to make this the unofficial "sequel".


• How is this course different from other iOS exploitation courses?
  Several ways:
  
  • First, we try and parallel OS X and iOS, in much the same way MOXiI has. In that, we are not focused on one or the other operating system, but take their (rather large) common denominator as a base, and make segues and side discussion for idiosyncratic features of one or the other.
    
  • Second, we do not demonstrate, sell or otherwise provide any active 0-days. We do, however, explain past vulnerabilities in great detail, as well as the exploitation methodology, which applies to the present day.
  • We present unparalleled views of kernel memory and objects using advanced tools, such as our proprietry Xn00p kernel memory inspector
  • Lastly, other trainings are myopic, focusing only on the exploitation. We believe that true understanding of the internals of a system goes further.


• When and where is the next course for this scheduled?
  The time has passed. Jonathan's last training was in Offensive Con 2024, as a 'special event' of sorts. There are presently no plans for this to be delivered publicly. You can, however, ask to be on our notification list, should that ever change.


• I don't have a (jailbroken) iOS device. What do I do?
  We strongly suggest bringing your own device. If you can't, talk to us - we can rent you one. No problem.


• Is it true what I hear about "surprise, mystery guests" attending your courses?
  If we admitted to anything, it wouldn't be a surprise, nor a mystery, now, would it? :-)


• How much??
  $3,500 per person - cheaper than most blackhat trainings! And - Discounts may apply as of the third student in the same group, or for previous alumni of Technologeeks courses.


• Can I take this remotely over Skype or similar medium?
  Not at this time, but we're (still) working on it.

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