Chapter 10

Question 1

Buffer overflow

Answer 1

more input can be placed into buffer /data holding area than capacity allocated, overwriting other info-crash system /gain control

Question 2

Consequences

Answer 2

1. corruption
2. transfer of control
3. memory access violations
4. execution of code

Question 3

Needs for buffer overflow attack

Answer 3

1. identify buffer overflow vulnerability in program
2. understand how buffer stored in memory

Question 4

Attacks

Answer 4

1. stack buffer overflows
2. Shellcode -code from attacker

Question 5

eax

Answer 5

arithmetical + IO operations + interrupt calls

Question 6

ebx

Answer 6

base register - access memory , pass system call arguments + return values

Question 7

ecx

Answer 7

count register

Question 8

edx

Answer 8

arithmetic, interrupt calls , IO operations

Question 9

ebp

Answer 9

base pointer - address of current stack frame

Question 10

eip

Answer 10

instruction pointer - address of next instruction

Question 11

esi

Answer 11

source index - pointer for string /array operations

Question 12

esp

Answer 12

stack pointer - address of top of stack

Question 13

Defenses - compile time

Answer 13

harden programs to resist attacks
1. high-level language
2. safe coding techniques
3. safe libraries
4. stack protection - function entry + exit code
- entry write copy of return address in safe space in memory
- exit check return address in stack against saved

Question 14

Defences - run time

Answer 14

1. executable address space protection
2. address space randomization
3. Guard pages - page between critical portions in memory

Question 15

replacement stack frame

Answer 15

way to get control using dummy stack frame

Question 16

Other attacks

Answer 16

1. replacement stack frame
2. global data overflow
3. heap overflow
4. return to system call - replace return address with library