Make PATH optional, also correct a filtering bug

If the PATH option is not specified, the module will try to
enumerate from %PATH%.  Also, this commit fixes a bug in the
filtering routine (basically the filtering routine didn't
really work).

modules/post/windows/gather/enum_dirperms.rb

@@ -10,16 +10,20 @@
 ##
 
 require 'msf/core'
-require 'rex'
+require 'msf/core/post/common'
 
 class Metasploit3 < Msf::Post
 
+	include Msf::Post::Common
+
 	def initialize(info={})
 		super(update_info(info,
 			'Name'           => "Windows Gather Directory Permissions Enumeration",
 			'Description'    => %q{
 				This module enumerates directories and lists the permissions set
-				on found directories.
+				on found directories. Please note: if the PATH option isn't specified,
+				then the module will start enumerate whatever is in the target machine's
+				%PATH% variable.
 			},
 			'License'        => MSF_LICENSE,
 			'Version'        => '$Revision$',
@@ -30,7 +34,7 @@ class Metasploit3 < Msf::Post
 
 		register_options(
 			[
-				OptString.new('PATH', [ true, 'Directory to begin search from', '']),
+				OptString.new('PATH', [ false, 'Directory to begin search from', '']),
 				OptEnum.new('FILTER', [ false, 'Filter to limit results by', 'NA', [ 'NA', 'R', 'W', 'RW' ]]),
 				OptInt.new('DEPTH', [ true, 'Depth to drill down into subdirs, O = no limit',0]),
 			], self.class)
@@ -90,40 +94,46 @@ class Metasploit3 < Msf::Post
 		if w["GrantedAccess"] > 0 then result << "W" end
 	end
 
-	def enum_subdirs(dpath, maxdepth, token)
+	def enum_subdirs(perm_filter, dpath, maxdepth, token)
 		filter = datastore['FILTER']
 		filter = nil if datastore['FILTER'] == 'NA'
+
 		dirs = session.fs.dir.foreach(dpath)
+
 		if maxdepth >= 1 or maxdepth < 0
 			dirs.each do|d|
 				next if d =~ /^(\.|\.\.)$/
 				realpath = dpath + '\\' + d
 				if session.fs.file.stat(realpath).directory?
 					perm = check_dir(realpath, token)
-					if !filter or perm.include? filter
+					if perm_filter and perm.include?(perm_filter)
 						print_status(perm + "\t" + realpath)
 					end
-					enum_subdirs(realpath, maxdepth - 1,token)
+					enum_subdirs(perm_filter, realpath, maxdepth - 1,token)
 				end
 			end
 		end
 	end
 
-	def run
-		t = 0 #holds impers token
+	def get_paths
+		p = datastore['PATH']
+		return [p] if not p.nil? and not p.empty?
 
-		#check and set vars
-		if not datastore['PATH'].empty?
-			path = datastore['PATH']
+		begin
+			p = cmd_exec("cmd.exe", "/c echo %PATH%")
+		rescue Rex::Post::Meterpreter::RequestError => e
+			vprint_error(e.message)
+			return []
+		end
+		print_status("Option 'PATH' isn't specified. Using system %PATH%")
+		if p.include?(';')
+			return p.split(';')
+		else
+			return [p]
+		end
 	end
 
-		depth = -1
-
-		if datastore['DEPTH'] > 0
-			depth = datastore['DEPTH']
-		end
-
-		#get impersonation token
+	def get_token
 		print_status("Getting impersonation token...")
 		begin
 			t = get_imperstoken()
@@ -133,19 +143,51 @@ class Metasploit3 < Msf::Post
 			vprint_error("Error #{e.message} while using get_imperstoken()")
 			vprint_error(e.backtrace)
 		end
+		return t
+	end
+
+	def enum_perms(perm_filter, token, depth, paths)
+		paths.each do |path|
+			next if path.empty?
+			path = path.strip
+
+			print_status("Checking directory permissions from: #{path}")
+
+			perm = check_dir(path, token)
+			if not perm.nil?
+				# Show the permission of the parent directory
+				if perm_filter and perm.include?(perm_filter)
+					print_status(perm + "\t" + path)
+				end
+
+				#call recursive function to loop through and check all sub directories
+				enum_subdirs(perm_filter, path, depth, token)
+			end
+		end
+	end
+
+	def run
+		perm_filter = datastore['FILTER']
+		perm_filter = nil if datastore['FILTER'] == 'NA'
+
+		paths = get_paths
+		if paths.empty?
+			print_error("Unable to get the path")
+			return
+		end
+
+		depth = -1
+		if datastore['DEPTH'] > 0
+			depth = datastore['DEPTH']
+		end
+
+		t = get_token
 
-		#loop through sub dirs if we have an impers token..else error
 		if t == 0
 			print_error("Getting impersonation token failed")
 		else
-			print_status("Got token...")
-			print_status("Checking directory permissions from: " + path)
-
-			is_path_valid = check_dir(path, t)
-			if not is_path_valid.nil?
-				#call recursive function to loop through and check all sub directories
-				enum_subdirs(path, depth, t)
-			end
+			print_status("Got token: #{t.to_s}...")
+			enum_perms(perm_filter, t, depth, paths)
 		end
 	end
 end