Attacking the Linux Kernel
4200€ | 9th to the 12th of October 2023 | Espace Vinci, Rue des Jeuneurs, Paris, France
This training guides researchers through the field of Linux kernel security. In a series of exercise-driven labs, the training explores the process of finding, assessing, and exploiting kernel bugs in a modern Linux distribution on the x86-64 architecture.
Besides providing a foundation for writing Linux kernel exploits, the training covers the no-less important areas of finding kernel bugs and evaluating their security impact. This includes chapters on using and extending dynamic bug-finding tools, writing custom fuzzers, and analyzing crashes.
The training starts with the beginner topics but proceeds into a few advanced areas as well.
Objectives of the training
Security-relevant Linux kernel internals and attack surface.
Usage, internals, and extension of Kernel Address Sanitizer (KASAN).
Writing and evaluating kernel-specific fuzzing harnesses.
Collecting kernel code coverage with KCOV.
Practical usage and basic internals of syzkaller.
Kernel privilege escalation techniques.
In-kernel Return-Oriented Programming (ROP).
KASLR, SMEP, SMAP, and KPTI bypasses.
Exploiting stack, global, and slab (heap) vulnerabilities.
Exploiting use-after-free (UAF) and out-of-bounds (OOB) vulnerabilities.
The trainer
Who will run this training?
Andrey
Konovalov
xairy.io
@andreyknvl
Andrey Konovalov is a security researcher focusing on the Linux kernel.
Andrey found multiple zero-day bugs in the Linux kernel and published proof-of-concept exploits for these bugs to demonstrate the impact. Andrey is a contributor to several security-related Linux kernel subsystems and tools: KASAN — a fast dynamic bug detector, syzkaller — a production-grade kernel fuzzer, and Arm Memory Tagging Extension (MTE) — an exploit mitigation.
Andrey spoke at security conferences such as OffensiveCon, Android Security Symposium, Linux Security Summit, LinuxCon, and PHDays. Andrey also maintains a collection of Linux kernel security–related materials and a channel on Linux kernel security.
See xairy.io for all Andrey's articles, talks, and projects.
Syllabus
What will we do?
Agenda
Day 1 — Internals and Sanitizers
- Internals and debugging: x86-64 architecture refresher; security-relevant Linux kernel internals and attack surface; types of kernel vulnerabilities; setting up a debugging environment with VMWare; using GDB to debug kernel and its modules.
- Detecting bugs: using KASAN to detect and analyze memory corruptions; KASAN internals and extension; reading kernel bug reports; assessing impact of kernel bugs.
Day 2 — Fuzzing
- General fuzzing: writing and evaluating kernel-specific fuzzing harnesses; Human-in-the-Loop fuzzing; collecting kernel code coverage with KCOV; using KCOV remote coverage.
- Fuzzing with syzkaller: API-aware fuzzing; coverage-guided fuzzing; using syzkaller; writing syscall descriptions.
Day 3 — Exploitation basics
- Escalating privileges: ret2usr, overwriting cred structure, overwriting modprobe_path; arbitrary address execution and arbitrary address read/write primitives.
- Bypassing mitigations: KASLR, SMEP, SMAP, and KPTI bypass techniques; in-kernel Return-Oriented Programming (ROP).
- Exploiting slab corruptions: slab out-of-bounds and use-after-free vulnerabilities; SLUB internals; slab spraying; slab-specific mitigations.
Day 4 — Modern slab exploitation
- Modern slab exploitation techniques: elastic objects; userfaultfd and FUSE; cross-cache attacks; data-only exploitation.
- Beyond: learning advanced exploitation techniques; useful references.
Student requirements
- Working C knowledge.
- Familiarity with x86-64 architecture and x86-64 assembly.
- Familiarity with GDB (GNU Debugger).
- Familiarity with common types of vulnerabilities and exploitation techniques for userspace applications.
No knowledge about Linux kernel internals is required.
Hardware requirements
- At least 100 GB of free disk space.
- At least 12 GB of RAM.
- Ability to plug in an untrusted USB drive (relevant for corporate laptops).
Software requirements
- Host OS: Linux (recommended) or Windows.
- VMWare Workstation Player.
- 7-Zip.
Provided to students
A USB drive with:
- Presentation slides.
- Detailed lab guides with step-by-step instructions.
- Virtual machine images with tools, exercise binaries, and source code.
Other trainings
What else might interest you?
Attacking Instant Messaging Applications
Vectorize (Nitay Artenstein & Iddo Eldor & Jacob Bech)