brute force mixin for exploits, untested

git-svn-id: file:///home/svn/incoming/trunk@2739 4d416f70-5f16-0410-b530-b9f4589650da

lib/msf/core/exploit/brute.rb

@@ -0,0 +1,167 @@
+module Msf
+
+###
+#
+# Brute
+# -----
+# 
+# This modules provides a target-aware brute-forcing wrapper.  It implements
+# the exploit method and calls exploit_brute with target supplied information.
+# If the selected target is not a bruteforce target, then exploit_single is
+# called.
+#
+###
+module Exploit::Brute
+
+	def initialize(info = {})
+		super
+
+		#
+		# Register BruteWait and BruteStep as two advanced options for this
+		# exploit even though not all targets may be brute force targets
+		#
+		register_advanced_options(
+			[
+				OptData.new('BruteWait', [ false, "Delay between brute force attempts"     ]),
+				OptData.new('BruteStep', [ false, "Step size between brute force attempts" ])
+			], Msf::Exploit::Brute)
+	end
+
+	#
+	# Entry point for initiating an exploit.  This module wrappers the exploit
+	# method and determines whether or not the selected target supports brute
+	# force.  If it does, it does some special things and wraps the brute
+	# forcing logic.
+	#
+	def exploit
+		# Is the selected target a brute force target?
+		if (target.bruteforce?)
+			# The step direction is automatically calculated
+			direction = {}
+
+			bf = target.bruteforce
+
+			# Get the start and stop address hashes
+			start = (bf.start_addresses && bf.start_address.dup) || {}
+			stop  = (bf.stop_addresses  && bf.stop_address.dup)  || {}
+			step  = bf.step_size
+			delay = bf.delay
+		
+			# Enumerate each start address and try to figure out the direction
+			start.each_pair { |name, addr|
+				# If there's a stop address, figure out if it's above or below
+				# the start address
+				if (stop[name])
+					if (stop[name] < addr)
+						direction[name] = -1
+					else
+						direction[name] = 1
+					end
+				# If there's no stop address, infer the direction based on
+				# the default
+				else
+					direction = bf.default_direction
+				end
+			}
+	
+			# Import start/stop address overrides from the datastore
+			import_from_datastore(start, 'Start')
+			import_from_datastore(stop,  'Stop')
+
+			# User-defined brute wait?
+			if (self.datastore['BruteWait'])
+				delay = self.datastore['BruteWait'].to_i
+			end
+
+			# User-defined brute step?
+			if (self.datastore['BruteStep'])
+				step = self.datastore['BruteStep'].to_i
+			end
+
+			# Okay, we've got all this crap out of the way, let's actually brute
+			# force
+			stopped = []
+			curr    = start.dup
+
+			# Keep going until we run out of options
+			while (curr.length != stopped.length)
+
+				# Fire off an exploit attempt with the supplied addresses
+				brute_exploit(curr)
+
+				# Give it time before we try again
+				brute_wait(delay)
+
+				# Scan each current key, increasing it or decreasing it by the
+				# step size according to its direction
+				curr.each_key { |k|
+
+					# Has movement been stopped on this address?  If so, skip it.
+					next if (stopped.include?(k))
+
+					# Calculate the next address before we move it to see if
+					# we're going to go over
+					next_addr = step_size * direction[k]
+
+					# If this item has hit a stop address, add it to the stopped 
+					# hash and move it no further
+					if (stop[k])
+						if ((direction[k] == 1 and next_addr >= stop[k]) or
+						    (direction[k] == -1 and next_addr < stop[k]))
+							 stopped << k
+							 next
+						end
+					end
+				
+					# If it's not time to stop, move it
+					curr[k] += next_addr
+				}
+			end
+		else
+			single_exploit
+		end
+	end
+
+	#
+	# This routine is called once per brute force iteration.  The addresses
+	# parameter is a hash of addresses that are incremented each iteration and
+	# are derived from the target's bruteforce information or the module's 
+	# datastore in case they are being overriden.
+	#
+	def brute_exploit(addrs)
+	end
+
+	#
+	# Call if the target is not a brute force target.
+	#
+	def single_exploit
+	end
+
+	#
+	# Waits for the provide delay
+	#
+	def brute_wait(delay)
+		sleep(delay)
+	end
+
+protected
+
+	#
+	# Imports information into the supplied hash from the datastore.
+	# This is a way of allowing the user to override values for a 
+	# specific brute force target by name without them actually 
+	# being conveyed in the options list.  This is a bit of a change
+	# from 2.x, but 2.x didn't have per-target brute force
+	# addresses, which I think is more valuable.
+	#
+	def import_from_datastore(hash, prefix = '')
+		hash.each_key { |k|
+			if (self.datastore[prefix + k])
+				hash[k] = self.datastore[prefix + k]
+			end
+		}
+	end
+
+end
+
+end