Topic 4: Exploitation basics

Question 1

what is executable & linkable format (ELF)?

Answer 1

common format for executable and library files on modern *nix systems

Question 2

what do all elf begin with?

Answer 2

“magic number” = 0x7F’E’‘L’‘F’

Question 3

what are sections / the 2 types?

Answer 3

organize binary into logical sections used by the linker and loaders
.bss is uninitialized data (global variables)
.text is code

Question 4

what are segments?

Answer 4

define the parts that should be loaded into memory and how the readelf command examines ELF file data

Question 5

what is process/what does it provide?

Answer 5

instance of a running program, provides each program with 2 key abstractions: logical control flow & private address space

Question 6

difference between virtual and physical memory?

Answer 6

can be larger than physical memory, virtual is always mapped, not all pages need to be in physical memory to run program

Question 7

when is address in kernel space?

Answer 7

if most significant bit is 1 otherwise its in user/application space

Question 8

what is heap / how is it accessed?

Answer 8

dynamically allocated data, malloc(), calloc(), realloc(), free()