GDB Debugger For Basic Debugging

Multiple Platform

• x86
• ARM
• Opensource and closed source binaries.

Uses of GDB :

• Runtime Analysis
• Manipulating Program Flow
• Disassembly
• Reverse Engineering

Debuggers Symbol

• Information about Variables, functions etc. About the binary which can be read by a debugger
• Debugger now Understands the binary better.
• It can be included in the binary , if not then it can be parsed separately . Symbol file types are Dwarf 2, COFF, XCOFF, Stabs
• GCC uses -g option
• GCC -ggbd for GDB Specific Symbols

NM -(List Symbols from Object Files)

nm 'File_name'

• Output :

• Symbol Types :

Commands:

• nm 'File_name' |grep 'function_name' (will find the symbol in the binary).
• nm ./* |grep 'function_name' (will find the symbol in every File in the given Directory)
• nm -n 'File_name'(Sort the output)

Strace :

• Helper tooll to understand how program interacts with the os.
• Traces all system calls made by the program
• strace 'File_name'

GDB Commands :

• info functions (Will give you all the functions)
• info variables(will give info about variables but by default it doesn't print local variables {only global variables})
• break main(Set a Breakpoint at main Function)
• info registers (Information of CPU Registers)

• info breakpoints (List all break Points)
• disable 'breakpoint number' (Disable Selected breakpoint)
• enable 'breakpoint number'(enable Breakpoint)
• delete 'breakpoint number'(delete breakpoint)