Software Deobfuscation Techniques

Instructors:Tim Blazytko
Dates: May 30- June 2 2022
Location: Hilton Double Tree
Capacity: 20 Seats

Code obfuscation has become a vital tool to protect, for example, intellectual property against competitors. In general, it attempts to impede program understanding by making the to-be-protected program more complex. As a consequence, a human analyst who still aims to reason about the obfuscated code has to overcome this barrier by transforming it into a representation that is easier to understand.

In this training, we get to know state-of-the-art code obfuscation techniques and have a look at how these complicate reverse engineering. Afterwards, we gradually become familiar with different deobfuscation techniques and use them to break obfuscation schemes in hands-on sessions. Thereby, participants will deepen their knowledge of program analysis and learn when and how (not) to use different techniques.

First, we have a look at important code obfuscation techniques and discuss how to attack them. Afterwards, we analyze a virtual machine-based (VM-based) obfuscation scheme, learn VM hardening techniques and see how to deal with them.

In the second part, we cover SMT-based program analysis. In detail, students learn how to solve program analysis problems with SMT solvers, how to prove characteristics of code, how to deobfuscate mixed Boolean-Arithmetic and how to break weak cryptography.

Before we use symbolic execution to automate large parts of code deobfuscation, we first introduce intermediate languages and compiler optimizations to simplify industrial-grade obfuscation schemes. Following, we use symbolic execution to automate SMT-based program analysis and break opaque predicates.

The last part covers program synthesis, an approach that learns the code's semantics based on its input-output behavior. We explore how to collect input-output pairs; then, we use program synthesis to deobfuscate mixed Boolean-Arithmetic and learn the semantics of VM instruction handlers.


Note that the training focuses on hands-on sessions. While some lecture parts provide an understanding of when to use which method, various hands-on sessions teach how to use them to build custom purpose tools for one-off problems. The trainer actively supports the students to successfully solve the given tasks. After a task is completed, we discuss different solutions in class. Furthermore, students receive detailed reference solutions that can be used during and after the course.

While the hands-on sessions use x86 assembly, all tools and techniques can also be applied to other architectures such as MIPS, PPC or ARM.


Class Outline

The training orientates at the following outline:

Class Requirements


Basic reverse engineering skills.

The participants should have basic reverse engineering skills. Furthermore, they should be familiar with x86 assembly and Python.

Minimum Software requirement:

Students should have access to a computer with 4 GB RAM (minimum) and at least 20 GB disk space. Furthermore, they should install a disassembler of their choice (e.g., IDA or Ghidra) as well as virtualization software such as Virtual Box or VMware. Students will be provided with a Linux VM containing all necessary tools and setups.


Tim Blazytko is a well-known binary security researcher and co-founder of emproof. After working on novel methods for code deobfuscation, fuzzing and root cause analysis during his PhD, Tim now builds code obfuscation schemes tailored to embedded devices. Moreover, he gives trainings on reverse engineering & code deobfuscation, analyzes malware and performs security audits.

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