##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Auxiliary

	include Msf::Exploit::Remote::Tcp
	include Msf::Auxiliary::Scanner
	include Msf::Auxiliary::Report

	def initialize
		super(
			'Name'        => 'Finger Service User Enumerator',
			'Description' => 'Identify valid users through the finger service using a variety of tricks',
			'Author'      => 'hdm',
			'License'     => MSF_LICENSE
		)
		register_options([
			Opt::RPORT(79),
			OptString.new('USERS_FILE',
				[ true, 'The file that contains a list of default UNIX accounts.',
					File.join(Msf::Config.install_root, 'data', 'wordlists', 'unix_users.txt')
				]
			)], self.class)
	end

	def run_host(ip)
		@users = {}

		begin
			vprint_status "#{rhost}:#{rport} - Sending empty finger request."
			finger_empty
			vprint_status "#{rhost}:#{rport} - Sending test finger requests."
			finger_zero
			finger_dot
			finger_chars
			vprint_status "#{rhost}:#{rport} - Sending finger request for user list: #{finger_user_common.join(", ")}"
			finger_list

		rescue ::Rex::ConnectionError
		rescue ::Exception => e
			print_error("#{e} #{e.backtrace}")
		end
		report_service(:host => rhost, :port => rport, :name => "finger")

		if(@users.empty?)
			print_status("#{ip}:#{rport} No users found.")
		else
			print_good("#{ip}:#{rport} Users found: #{@users.keys.sort.join(", ")}")
			report_note(
				:host => rhost,
				:port => rport,
				:type => 'finger.users',
				:data => {:users => @users.keys}
			)
		end
	end


	def finger_empty
		connect
		sock.put("\r\n")
		buff = finger_slurp_data
		parse_users(buff)
		disconnect
	end

	def finger_zero
		connect
		sock.put("0\r\n")
		buff = finger_slurp_data
		parse_users(buff)
		disconnect
	end

	def finger_dot
		connect
		sock.put(".\r\n")
		buff = finger_slurp_data
		parse_users(buff)
		disconnect
	end

	def finger_chars
		connect
		sock.put("m m m m m m m m\r\n")
		buff = finger_slurp_data
		if buff.scan(/\r?\nm\s/).size > 7
			@multiple_requests = true
			vprint_status "#{rhost}:#{rport} - Multiple users per request is okay."
		end
		parse_users(buff)
		disconnect
	end

	def finger_list
		if !@multiple_requests
			finger_user_common.each do |user|
				next if @users[user]
				connect
				vprint_status "#{rhost}:#{rport} - Sending finger request for #{user}..."
				sock.put("#{user}\r\n")
				buff = finger_slurp_data
				ret = parse_users(buff)
				disconnect
				break if not ret
			end
		else
			while !finger_user_common.empty?
				user_batch = []
				while user_batch.size < 8 and !finger_user_common.empty?
					new_user = finger_user_common.shift
					next if @users.keys.include? new_user
					user_batch << new_user
				end
				connect
				vprint_status "#{rhost}:#{rport} - Sending finger request for #{user_batch.join(", ")}..."
				sock.put("#{user_batch.join(" ")}\r\n")
				buff = finger_slurp_data
				ret = parse_users(buff)
				disconnect
				break if not ret
			end
		end
	end

	def finger_slurp_data
		buff = ""
		begin
			while(res = sock.get_once(-1, 5) || '')
				buff << res
				break if buff.length > (1024*1024)
			end
		rescue ::Interrupt
			raise $!
		rescue ::Exception
		end
		buff
	end

	def finger_user_common
		if(! @common)
			File.open(datastore['USERS_FILE'], "rb") do |fd|
				data = fd.read(fd.stat.size)
				@common = data.split(/\n/).compact.uniq
				@common.delete("")
			end
		end
		@common
	end

	def parse_users(buff)
		buff.each_line do |line|
			uid = nil
			next if line.strip.empty?

			# Ignore Cisco systems
			return if line =~ /Line.*User.*Host.*Location/

			next if line =~ /user not found/i
			next if line =~ /no such user/i
			next if line =~ /must provide username/
			next if line =~ /real life: \?\?\?/
			next if line =~ /No one logged on/
			next if line =~ /^Login\s+Name\s+TTY/

			# print_status(">> #{line}")

			# No such file or directory == valid user bad utmp

			# Solaris
			if(line =~ /^([a-z0-9\.\_]+)\s+([^\s]+)\s+([^\s]+)\s+([^\s]+)\s+([^\s]+)/)
				uid = $1
				if ($2 != "Name")
					@users[uid] ||= {}
				end
			end

			# IRIX
			if(line =~ /^\s*Login name:\s*([^\s]+)\s+/i)
				uid = $1
				@users[uid] ||= {} if uid
			end

			# Debian GNU/Linux
			if(line =~ /^\s*Username:\s*([^\s]+)\s+/i)
				uid = $1
				@users[uid] ||= {} if uid
			end

			if uid
				print_good "#{rhost}:#{rport} - Found user: #{uid}" unless @users[uid] == :reported
				@users[uid] = :reported
				next
			end
		end
		return true
	end

end