System Level Programming Software College of SCU

System Level ProgrammingSoftware College of SCU Lab：Binary Bomb 1

Binary Bomb Lab • 1. Lab Discription • 2. Tools to "Defuse" Bombs • 3. Defuse Bomb 1

Lab discription The "binary bomb" is an executable c program provided as a binary object file. Run the program, it prompts the user to type in 6 different strings. If any of these is incorrect, the bomb "explodes" by printing an error message “BOOM!!!”. 1. Lab Discription(1/2)

1. Lab Discription(2/2) The source code for phase_1() and others are not provided. Students will use reverse engineer to find out 6 input string.

Binary Bomb Lab • 1. Lab Discription • 2. Tools to "Defuse" Bombs • 3. Defuse Bomb 1

How to "DEFUSE'' the bomb disassembling the binary object file to assembly instructions disassembler: objdump.exe objdump -d bomb.exe >> bomb.ass disassembling object file bomb.exe and redirect the instructions to plaintext file bomb.ass Refers to objdump_Tutorial.pdf to get more info 2. Tools to "Defuse" Bombs(1/3)

How to "DEFUSE'' the bomb single-step through the instruction in each phase to figure out the "strings" debugger: gdb.exe GDB is the standard debugger that runs on many unix-like systems and works for many programming language including c. Refers to gdb_Tutorial.pdf to get more info 2. Tools to "Defuse" Bombs(2/3)

2. Tools to "Defuse" Bombs(3/3) • GDB 跟踪调试常用命令 • 反汇编：objdump -d bomb • 查看所有寄存器内容：info registers • 打印某一寄存器：p $eip • 打印内存内容： x 0x8049034 • 打印内存内容（以字符串形式）：x/s 0x8049034 • 设置断点：b • 设置断点（地址）： b*0x8049034 • 运行：run • 执行单步： si

Binary Bomb Lab • 1. Lab Discription • 2. Tools to "Defuse" Bombs • 3. Defuse Phase 1

3. Defuse Phase 1(1/2)

3. Defuse Bomb 1(2/2)

System Level Programming Software College of SCU