1. Reverse Engineering for CTFs
Unit 2

2. Last lecture Went over basics of RE Touched on x86
Static analysis with Radare2

3. This lecture Homework Recap Emulation and virtualization with QEMU
Dynamic analysis with gdb and pwndbg
Demo
Homework

4. QEMU
QEMU is a generic and open source machine emulator and virtualizer.
Has full system emulation and virtualization technology, but for this class/homework we are interested in user-mode emulation.
User-mode emulation: Run programs for another Linux/BSD target, on any supported architecture
General Plan:
Identify the correct architecture for the file.
Google/man page/read the docs to find the correct qemu command to run your file.
Install: (This will take a while!)
git clone git://git.qemu.org/qemu.git
cd qemu
git submodule init
git submodule update --recursive
./configure (May also need to run sudo apt install libpixman-1-dev)
make

5. QEMU Example

6. pwndbg pwndbg is a GDB plug-in to improve debugging with GDB. Install:
git clone
cd pwndbg
./setup.sh

7. pwndbg Commands: gdb fileToAnalysis - Start pwndbg
start - Sets a breakpoint at main and executes.
c - continue execution
b *Address - set a breakpoint at Address
s n - Step n instructions
n - next instruction. (Avoid stepping into interesting functions)
set $reg = value - Set the register $reg equal to value.
r2 - Opens Radare2